MEMORANDUM DECISION AND ORDER RE: BAC DEFENDANTS' MOTION FOR PARTIAL SUMMARY JUDGMENT; DAUBERT MOTIONS

OLIVER W. WANGER, District Judge.

I. INTRODUCTION.

This lawsuit arises out of a now-closed cooling tower manufacturing facility (the "BAC site") that pressure treated wood and was operated by entities formerly owned by the BAC Defendants ("BAC").1 Plaintiffs, current or former residents of residential neighborhoods ("Beachwood") near the BAC Site,2 allege that two contaminants from the BAC Site migrated from the treating area via groundwater, surface water, surface soil, private well, and air pathways to locations where plaintiffs were exposed to them.3 Also named as defendants are various municipalities, water districts, and developers, including the Franklin County Water District, Merced Irrigation District, the City and County of Merced, and the Meadowbrook Water District.4

Before the court for decision is BAC Defendants' motion to summarily adjudicate Plaintiffs' tenth, twelfth, thirteenth, and fourteenth causes of action. According to Defendants, Plaintiffs have failed to present any admissible evidence of actual exposure to contaminants from the BAC site, via any pathway, which was required under "Phase 1" of the Court's "Order Modifying Scheduling Conference Order." (Doc. 540.) The first phase of discovery was to focus on "whether contaminants from the former [ ] BAC Site, Franklin County Water District or the April 2006 Flood have ever reached any location where plaintiffs could have been exposed to them, and if so, when such contaminants arrived, how such contaminants arrived at the location, how long they were present, and at what levels they were present." (Id. at 1:14-1:28.) By this motion, the BAC Defendants assert that Plaintiffs have not met their "Phase 1" or "general exposure" burden, entitling them to partial summary judgment.

Plaintiffs opposed the motion on July 1, 2010, submitting over 3,000 pages of documentation and 168 exhibits. Plaintiffs' opposition is founded on their claim that they have presented "substantial evidence" in the form of expert opinion and analysis to show that contaminants migrated from the BAC facility to Plaintiffs' homes and/or properties. Plaintiffs further argue that the BAC Defendants' motions to exclude certain expert testimony fail because their criticisms go to its weight, not its admissibility.

Oral argument on the BAC Defendants' motions was held on October 6, 7, 13, 14, and 15, 2010, during which the parties presented argument and evidence relevant to the Phase 1 pathway exposure issues. The parties were permitted to introduce expert testimony on key scientific issues, namely the methodologies and assumptions used to model contamination via the groundwater and air pathways. The testifying experts were examined by counsel for Plaintiffs and Defendants, as well as the Court.5

On October 22 and November 1, 2010, the parties were advised the Court intended to appoint independent experts under Fed.R.Evid. 706 to assist in the understanding and resolving the complex scientific disputes over groundwater and air modeling. The analysis included determining concentration levels of hexavalent chromium and/or arsenic in Meadowbrook Well No. 2 and surrounding areas (i.e., monitor networks and private wells), as well as the assumptions/calculations underlying the air model. The Fed.R.Evid. 706 Experts were appointed on October, 26. 2010 (Kenneth D. Schmidt, Ph.D.—groundwater) and November 1, 2010 (Chatten Cowherd Jr., Ph.D. and Richard Countess, Ph. D.—air).6 The parties and the Court jointly prepared a list of questions for the experts, which were transmitted to the experts in early November. The independent expert reports were submitted to the Court on November 22, 2010.7

The Fed.R.Evid. 706 experts were examined by the Court and parties on December 2, 3, and 15, 2010. Rebuttal testimony was permitted on a limited basis.8

The Rule 56 motions were submitted for decision following summation arguments on December 28 and 29, 2010.

II. FACTUAL BACKGROUND.9

The facts underlying this case are summarized in the Court's previous Memorandum Decisions in this case, filed on November 13, 2008, May 18, 2009, and July 15, 2009, in brief:10 approximately 2,100 Plaintiffs seek damages relating to two occurrences: (1) an April 2006 flood; and (2) alleged long-term contamination released from the former site of a cooling tower manufacturing facility operated by entities formerly owned by the BAC Defendants. The now-closed facility, which is the alleged source of contamination, is located in Merced, California, approximately 1,600 feet southwest from Meadowbrook Well No. 2 ("MWC-2"), which was the primary well supplying domestic water to the Beachwood community, until it was taken out of service in March 2008. Plaintiffs allege that MWC-2, which was operated by the Meadowbrook Water District, was contaminated by hexavalent chromium and total chromium in the well and from the aquifer, which drew on the contaminated plume during times of high water production, and exposed Plaintiffs to contaminants.11

It is further alleged that the remaining defendants contributed to Plaintiffs' exposure to carcinogens and/or toxins based on their operation of a nearby drainage system (City and County of Merced), a collection system and ponds (Franklin County Water District), and an irrigation canal (Merced Irrigation District).12 According to Plaintiffs, these municipalities and water districts were "direct participants" in the contamination based on their location and significance to the local community's water supply.

A. History and Remediation of BAC Site

From 1969 until 1984, the BAC Site housed a cooling tower manufacturing facility and BAC-Pritchard, Inc., the operator/owner, used pressure-treated wood to make cooling tower frames.13 The wood was treated in an on-site cylindrical vessel (retort), using two different solutions. Specifically, from 1969 until 1980, the wood was treated with a solution of chromium, copper, and arsenic ("CCA"). In 1980, BAC-Pritchard stopped using arsenic and instead used a solution of acid, copper, and chromium ("ACC"). BAC-Pritchard ceased treating wood at the site in May 1991 and the facility was closed in early 1994.14

The BAC Defendants acknowledge that elevated levels of hexavalent chromium and arsenic were discovered at the BAC Site as early as 1986. That same year, BAC Defendants hired an environmental consultant to investigate and implement a number of remedial measures associated with contamination at the Site. The retained consultant found elevated levels of hexavalent chromium and arsenic in the soil at the BAC Site. Subsequent consultants found hexavalent chromium and arsenic in groundwater beneath the Site and in a stormwater pond located on the southeastern portion of the Site.15

In 1991, IT Corporation, a remediation consultant hired by Merck and Amsted, completed a "clean closure" of the storm water pond. The closure involved excavating contaminated soil from the pond and disposing of it at a landfill under the supervision of the California Department of Toxic Substances Control ("DTSC"). In 1993 and 1994, IT Corp., under the supervision of the Regional Water Quality Control Board ("RWQCB"), installed a pump-and-treat groundwater remediation system to control migration of contaminants beneath and off of the Site and to remove hexavalent chromium and arsenic from groundwater. IT Corp. continued to expand and modify the groundwater treatment system through 2005.

In 1994, as part of the cleanup efforts, IT Corp. prepared a health risk assessment for the BAC Site. According to BAC Defendants, the health risk assessment employed "conservative exposure assumptions" to protect public health and was premised on the fact that no further remediation would take place. Based on these assumptions, IT Corp. determined that contamination at the Site created a cancer risk of two in one million (ratio of 2:1,000,000). The BAC Defendants assert that the DTSC employs a ratio of one in one million (1:1,000,000) to determine whether additional remediation should be performed.16

IT Corp.'s risk assessment did not evaluate the risk posed by the Site in the past (pre-1994), but looked prospectively at the future risk the Site might create if no further remediation was performed. IT Corp.'s risk assessment determined that if soils in the area of the former pressure-treating system were excavated or capped, that would "effectively eliminate the exposure pathways (and subsequent risk)." In 1996, IT Corp. completed excavation of contaminated soil from the area of the former pressure-treating system and installed a four-inch thick asphalt cap over the entire area. The BAC Defendants maintain that the excavation and cap "effectively eliminated the risks identified in the 1994 risk assessment."

Additional remediation at the BAC Site was performed in the mid to late-2000's by Arcadis, Inc., an environmental consulting firm to the BAC Defendants, which was paid $17 million to complete the cleanup of the BAC Site. This included excavation of the contaminated soil beneath the asphalt cap installed in 1996. Once the soil was removed, Arcadis re-paved the exposed soil. Arcadis also treated the groundwater with methanol to convert the hexavalent chromium to the more benign trivalent chromium. The groundwater treatment is expected to be completed within a few years, at which point the BAC Site will be monitored by the RWQCB until its final closure.

BAC Defendants assert that they have spent approximately $39 million remediating the BAC Site.

B. RWQCB Involvement—2007

In 2007, the RWQCB announced the availability for public review of a revised cleanup plan for the BAC Site.17 According to the BAC Defendants, the RWQCB solicited comments from the community and held an informational meeting to discuss the status of the BAC Site remediation. Following the public comment period, in May 2007, the RWQCB published a "fact sheet" regarding remediation of the Site, which purportedly expressed the RWQCB's opinion that contaminants "posed no health risk to residents in the vicinity of the Site." The BAC Defendants assert that the RWQCB's "fact sheet" expressed several additional opinions re: the BAC Site:

(Doc. 677-2 at 7:4-7:7.)

C. 2009 RWQCB Briefing to Senator Dianne Feinstein

On January 15, 2009, the RWQCB provided a "briefing paper" on the BAC Site in response to an inquiry by Senator Diane Feinstein. (Doc. 725-4.) The brief "provide[d] a description of the environmental conditions at the site, as well as a summary of the regulatory actions and cleanup responses taken at the site to address hexavalent chromium contamination." (Id.) In the brief, the RWQCB summarized its regulatory involvement, which commenced in 1987, and concluded that "[b]ased upon a thorough review of all of the data currently in the Central Valley Water Board's files, Board staff believe that the public is not being exposed to harmful levels of hazardous substances originating from the BAC site."18 Key details of the RWQCB's briefing are summarized as follows:

(Doc. 725-4 at pgs. 2-3.)

The RWQCB's briefing contained a detailed review of the groundwater pollution and cleanup at the BAC Site:

(Id. at pgs. 7-8.)

The RWQCB attached a table summary of water supply well data for hexavalent chromium from public water supply systems near the Beachwood neighborhood, specifically, Meadowbrook Water Company, the City of Atwater and Winton Water District.20 All of the Meadowbrook wells tested within background levels, including MWC-2 and MWC-4. The RWQCB noted: "For comparison purposes, a number of supply wells for the City of Los Banos, located approximately 25 miles southwest of the site, contain higher levels of hexavalent chromium [than the three closest public water supply systems]."

In its "closing observations," the RWQCB stated that "the public is not currently being exposed to harmful substances originating from the BAC Site," and that the cleanup actions "appear reasonable under the circumstances and the cleanup is proceeding in a satisfactory manner." (Id. at pg. 12.)

D. Plaintiffs' Response to BAC Site History/Remediation

Plaintiffs do not specifically dispute the BAC Defendants' recitation of the BAC Site history, including the remediation and RWQCB involvement, rather they take issue with the testing data used to support the BAC Defendants' motions. In particular, Plaintiffs argue that the data from the monitoring wells and MWC-2 Well is unreliable and/or inaccurate for the following reasons, among others: (1) the monitoring wells are too shallow; (2) the use of "selective" and/or "interval sampling"; and (3) the "honor system" employed by the Meadowbrook Water District lacks the necessary formalities to assure accurate records. Based on these factors, Plaintiffs' groundwater modeler, Mr. Douglas Bartlett, allegedly excluded portions of the sampling data from his modeling and analyses. The exclusion, if any, of the MWC-2 and monitoring well testing data is heavily disputed among the parties and forms the basis for BAC Defendants' motion to exclude Bartlett's expert testimony and model.

Plaintiffs also allege that several public entities, including the RWQCB and Defendants Meadowbrook Water District, Merced Irrigation District, and Merced County conspired with the BAC Defendants to: avoid collecting data from the MWC-2 Well, hide documents from third parties, and conceal the true danger/risk of the contaminants at or near the BAC Site. In particular, Plaintiffs contend that the BAC Defendants "conceal[ed] from the Regional Board [RWQCB] and plaintiffs [ ] the Arcadis groundwater modeling findings concerning the impact of MWC-2 on the contaminated plume." Plaintiffs further allege: "The draft report addressing [Arcadis'] model which was to be submitted to the Regional Board in December of 2007, was altered by Merck by deleting references to the findings of the model and by deleting a graphic illustration of contaminants flowing from the BAC directly into MWC-2."

III. PROCEDURAL BACKGROUND.

On March 8, 2007, Plaintiffs commenced this civil action against the current public entity defendants, alleging property damage caused by the April 2006 flood. (Doc. 1.) On September 13, 2007, in the second amended complaint, Plaintiffs named Merck & Co., Inc., Amsted Industries, Inc., Baltimore Aircoil Company, and Track Four, Inc. as Defendants in this action. (Doc. 35.) The operative complaint, the eighth amended complaint, was filed by Plaintiffs on March 26, 2010. (Doc. 633.) The eighth amended complaint alleges ten claims against the BAC Defendants: (1) violation of 42 U.S.C. § 6972(a)(1) [RCRA]; (2) violation of 42 U.S.C. § 6972(a)(1)(b) [RCRA]; violation of 33 U.S.C. § 1311(a) [CWA]; (4) violation of 33 U.S.C. § 1342(a) and (b) [CWA]; (5) negligence; (6) trespass; (7) nuisance; (8) wrongful death; (9) fraud and deceit; and (10) civil conspiracy.

On March 23, 2009, BAC Defendants filed a "Motion for Case Management Order Re: Exposure" to "compel plaintiffs to make a prima facie showing of exposure." (Doc. 355.) The motion was denied on July 6, 2009, however, on August 12, 2009, the Court established a multi-phase trial plan in which case-wide exposure issues were to be tried first ("Phase 1"), before general medical causation ("Phase 2") and plaintiff-specific exposure and causation ("Phase 3"). The August 12, 2009 "Order Modifying Scheduling Conference Order" provides, in relevant part:

(Doc. 540 at 1:14-1:28.)

On June 1, 2010, BAC Defendants moved for partial summary judgment on Plaintiffs' state law tort claims for personal injury and property damages, i.e., Plaintiffs' claims for negligence (Claim X), trespass (Claim XII), nuisance (Claim XIII), and wrongful death (Claim XIV).21 (Doc. 677.) According to Defendants, Plaintiffs have failed to produce evidence sufficient to show that any plaintiff was exposed to contaminants allegedly released from the former BAC Site located in Merced, California. BAC Defendants argue that since there is no contamination evidence, there is no genuine issue of material fact on the threshold issue of causation.

In support of their motion, BAC Defendants submit: (1) a Memorandum of Points and Authorities ("Memorandum"); (2) a Statement of Undisputed Facts in Support of its Motion; (3) the declarations of attorney R. Morgan Gilhuly and experts Scott Fendorf, Daniel B. Stephens, John L. Wilson, and Paolo Zannetti; and (4) separate motions to exclude the testimony of Plaintiffs' groundwater expert, Douglas Bartlett, and air expert, Camille Sears.

Plaintiffs opposed the motion on July 1, 2010, submitting over 3,000 pages of documentation and 168 exhibits.22 Plaintiffs oppose summary judgment on grounds that they have "substantial evidence" supporting their contention that "contaminants from the BAC facility have historically migrated from the [BAC] facility via groundwater, surface water and air pathways to locations were exposed to them and at levels which could cause harm." In particular, Plaintiffs argue that Sears and Bartlett's expert testimony is admissible and creates "competing expert opinions as to the migration of the contaminants from the BAC facility." According to Plaintiffs, Sears and Bartlett's expert opinions, by themselves, are sufficient to withstand a Rule 56 challenge.23

BAC Defendants filed their reply briefs on August 13, 2010.24 (Docs. 834 & 835.)

IV. LEGAL STANDARD.

Summary judgment/adjudication is appropriate when "the pleadings, the discovery and disclosure materials on file, and any affidavits show that there is no genuine issue as to any material fact and that the movant is entitled to judgment as a matter of law." Fed.R.Civ.P. 56(c). The movant "always bears the initial responsibility of informing the district court of the basis for its motion, and identifying those portions of the pleadings, depositions, answers to interrogatories, and admissions on file, together with the affidavits, if any, which it believes demonstrate the absence of a genuine issue of material fact." Celotex Corp. v. Catrett, 477 U.S. 317, 323, 106 S.Ct. 2548, 91 L.Ed.2d 265 (1986) (internal quotation marks omitted).

Where the movant will have the burden of proof on an issue at trial, it must "affirmatively demonstrate that no reasonable trier of fact could find other than for the moving party." Soremekun v. Thrifty Payless, Inc., 509 F.3d 978, 984 (9th Cir. 2007). With respect to an issue as to which the non-moving party will have the burden of proof, the movant "can prevail merely by pointing out that there is an absence of evidence to support the nonmoving party's case." Soremekun, 509 F.3d at 984.

When a motion for summary judgment is properly made and supported, the non-movant cannot defeat the motion by resting upon the allegations or denials of its own pleading, rather the "non-moving party must set forth, by affidavit or as otherwise provided in Rule 56, `specific facts showing that there is a genuine issue for trial.'" Soremekun, 509 F.3d at 984. (quoting Anderson v. Liberty Lobby, Inc., 477 U.S. 242, 250, 106 S.Ct. 2505, 91 L.Ed.2d 202 (1986)). "A non-movant's bald assertions or a mere scintilla of evidence in his favor are both insufficient to withstand summary judgment." FTC v. Stefanchik, 559 F.3d 924, 929 (9th Cir. 2009). "[A] non-movant must show a genuine issue of material fact by presenting affirmative evidence from which a jury could find in his favor." Id. (emphasis in original). "[S]ummary judgment will not lie if [a] dispute about a material fact is `genuine,' that is, if the evidence is such that a reasonable jury could return a verdict for the nonmoving party." Anderson, 477 U.S. at 248, 106 S.Ct. 2505. In determining whether a genuine dispute exists, a district court does not make credibility determinations; rather, the "evidence of the non-movant is to be believed, and all justifiable inferences are to be drawn in his favor." Id. at 255, 106 S.Ct. 2505.

V. DISCUSSION.

A. Introduction

Defendants move for summary judgment on Plaintiffs' negligence, trespass, nuisance, and wrongful death causes of action. Defendants' claim there is no evidence of exposure via any pathway, i.e., groundwater, private domestic wells, surface water, air, or soil. Plaintiffs oppose each facet of Defendants' motion, arguing that their expert evidence clearly shows that "contaminants from the BAC have historically migrated from the facility via groundwater, surface water, and air pathways to locations were plaintiffs were exposed to them and at levels which could cause harm." (Doc. 792 at 1:6-1:9.)

The substance of the parties' briefing, more than 5,000 pages of argument and expert/scientific reports, focuses on two pathways, groundwater and air. As to these pathways, Plaintiffs support their Phase 1 exposure burden with the testimony of Douglas Bartlett, groundwater hydrologist (groundwater modeler), and Camille Sears, meteorologist (air modeler). Defendants move to exclude these expert opinions and testimony pursuant to Federal Rule of Evidence 702 and two United States Supreme Court cases, Daubert v. Merrell Dow Pharms., Inc., 509 U.S. 579, 113 S.Ct. 2786, 125 L.Ed.2d 469 and Kumho Tire Co. v. Carmichael, 526 U.S. 137, 119 S.Ct. 1167, 143 L.Ed.2d 238 (1999). In particular, Defendants challenge Bartlett and Sears' expert testimony on grounds that it cannot pass Daubert's "gatekeeping" requirement.

B. Daubert Legal Standard

Rule 702 governs the admissibility of expert testimony. Pursuant to Rule 702, a witness qualified as an expert in "scientific... knowledge" may testify thereto if: "(1) the testimony is based upon sufficient facts or data; (2) the testimony is the product of reliable principles and methods; and (3) the witness has applied the principles and methods to the facts of the case." Fed. R.Evid. 702.

The trial court acts as a gatekeeper to the admission of expert scientific testimony under Rule 702. Daubert, 509 U.S. at 579-580, 113 S.Ct. 2786. The court must conduct a preliminary assessment to "ensure that any and all scientific testimony or evidence admitted is not only relevant but reliable." Id. at 589, 113 S.Ct. 2786. This two-step assessment requires consideration of whether (1) the reasoning or methodology underlying the testimony is scientifically valid (the reliability prong); and (2) whether the reasoning or methodology properly can be applied to the facts in issue (the relevancy prong). Id. at 592-93, 113 S.Ct. 2786; Kennedy v. Collagen Corp., 161 F.3d 1226, 1228 (9th Cir.1998).

Reliable testimony must be grounded in the methods and procedures of science and signify something beyond "subjective belief or unsupported speculation." Daubert, 509 U.S. at 590, 113 S.Ct. 2786. The inferences or assertions drawn by the expert must be derived by the scientific method. Id. In essence, the court must determine whether the expert's work product amounts to "`good science.'" Daubert v. Merrell Dow Pharms., Inc., 43 F.3d 1311, 1315 (9th Cir.1995) ("Daubert II") (quoting Daubert, 509 U.S. at 593, 113 S.Ct. 2786). In Daubert, the Supreme Court outlined factors relevant to the reliability prong, including: (1) whether the theory can be and has been tested; (2) whether it has been subjected to peer review; (3) the known or potential rate of error; and (4) whether the theory or methodology employed is generally accepted in the relevant scientific community. Daubert, 509 U.S. at 593-94, 113 S.Ct. 2786. The Supreme Court emphasized the "flexible" nature of this inquiry. Id. at 594, 113 S.Ct. 2786. As later confirmed in Kumho Tire Co. v. Carmichael, 526 U.S. 137, 119 S.Ct. 1167, 143 L.Ed.2d 238 (1999): "Daubert's list of specific factors neither necessarily nor exclusively applies to all experts or in every case. Rather the law grants a district court the same broad latitude when it decides how to determine reliability as [the court] enjoys in respect to its ultimate reliability determination." Id. at 141-42, 119 S.Ct. 1167.

The relevancy, or "fit," prong requires that the testimony be "relevant to the task at hand, ... i.e., that it logically advances a material aspect of the proposing party's case." Daubert II, 43 F.3d at 1315 (quoting Daubert, 509 U.S. at 597, 113 S.Ct. 2786). Relevancy requires opinions that would assist the trier of fact in reaching a conclusion necessary to the case. See Kennedy, 161 F.3d at 1230.

The Daubert analysis focuses on the principles and methodology underlying an expert's testimony, not on the expert's conclusions. Daubert, 509 U.S. at 595, 113 S.Ct. 2786. However, the Supreme Court has cautioned that "conclusions and methodology are not entirely distinct from one another." General Elec. v. Joiner, 522 U.S. 136, 146, 118 S.Ct. 512, 139 L.Ed.2d 508 (1997). As such, "[a] court may conclude that there is simply too great an analytical gap between the data and the opinion proffered." Id. Nothing in either Daubert or the Federal Rules of Evidence requires the admission of opinion evidence connected to existing data "only by the ipse dixit of the expert." Id.

C. Pathway # 1—Air

Plaintiffs allege that soil contaminated with hexavalent chromium and/or arsenic was transported to their homes or properties via wind and other airborne pathways. To satisfy their Phase 1 burden on the air pathway, Plaintiffs submit: (1) the expert testimony of air modeler Camille Sears (air exposure for the years 1969-1993); and (2) a 1994 Risk Assessment completed by IT Corp (air exposure post-1993 years).

Defendants contend that summary judgment is appropriate with respect to any air pathway because Plaintiffs' expert's testimony is inadmissible under Daubert. Specifically, Defendants move to exclude Ms. Sears' testimony on grounds that: (1) she is not qualified to perform soil calculations; (2) her entire emission scenario is flawed and lacks scientific reliability; and (3) her input parameters are scientifically unsound. As to the Risk Assessment, Defendants assert that it has no evidentiary value because "it was based on a hypothetical scenario that never occurred, and it does not purport to accurately calculate actual exposure or risks." (Doc. 677-2 at 23:18-23:19.) To support their Daubert motion, Defendants rely on the declaration and testimony of Dr. Paulo Zanetti, an air modeler, and Dr. Scott Fendorf, a chemist. Both these experts opine that Ms. Sears' model is scientifically unreliable.

Plaintiffs rejoin that Ms. Sears has performed similar soil calculations in modeling air dispersion, her emission scenario is well-accepted in the air modeling community and the dispute over her input parameters bear on the weight of the opinion rather than on its admissibility.

1. Fed.R.Evid. 706

Based on the extent of the dispute between the parties' experts and the complexity of the scientific issues presented by air modeling, the Court retained two independent experts, Chatten Cowherd Jr., Ph.D. and Richard Countess, Ph.D., under Fed.R.Evid. 706, to assist in the understanding and analyzing the air pathway dispute.25 Drs. Countess and Cowherd prepared a joint expert report, submitted on November 22, 2010. (Doc. 942.) The joint independent expert report and the opinions contained therein are discussed in the context of Defendants' criticisms of the air model.

2. Supplemental Briefing & Fed.R.Evid. 706 Experts

The parties filed supplement briefing concerning the air expert reports on November 29, 2010. The supplemental arguments mirror those advanced in the parties' earlier briefing, however, Plaintiffs reiterate that "the FRE 706 reports serve only to confirm the grave concerns plaintiffs have repeatedly expressed to this Court related to these Daubert proceedings." Plaintiffs contend that the Court "may be tempted to act as a trier of fact by weighing the relative strengths and weaknesses of factual and scientific assumptions made by the experts."26 They further assert that the air model disagreements "go to the weight of their opinions, and not their admissibility."

Defendants rejoin that the 706 expert reports "confirm[] that Plaintiffs' groundwater and air models contain serious methodological flaws, including faulty assumptions unsupported by science or facts, and are not reliable." Responding to Plaintiffs' "weight" arguments, Defendants assert that if Ms. Sears' expert report is either unreliable or irrelevant, it is inadmissible.27 An inadmissible report cannot create a disputed issue of fact. BAC Defendants also include a string citation to a number of federal cases holding that, under Daubert, an expert opinion cannot be "based on assumptions of fact without evidentiary support, or on speculative or conjectural factors."

3. Testimony/Model of Camille Sears (1969-1993)

Plaintiffs designated Sears as an air pathways expert who will opine on whether Plaintiffs' homes were exposed to significantly elevated air concentrations of hexavalent chromium and arsenic.28 Sears' declaration specifies she has worked in the air quality field since January 1982, following her graduation from the University of California at Davis (M.S. and B.S. degrees in atmospheric science). Prior to forming her own consulting firm in 1992, Sears worked as a private air consultant/scientist (Dames & Moore, URS Consultants) and Air Toxics Program Coordinator (Santa Barbara Air Pollution Control District). Sears has been a testifying expert for twenty years, since 1990, and provided air modeling testimony in California Dept. of Toxic Substances Control v. Interstate Non-Ferrous Corp., No. 97-CV-5016-OWW-LJO, an environmental contamination case involving, among other things, the alleged air dispersion of dioxin-containing ash released from incendiary operations at a smelting site in Mojave, California.

According to her expert reports, declarations, and testimony, Sears' followed a three-step process. First, she calculated air concentrations and surface deposition of hexavalent chromium and arsenic resulting from the BAC site based on "widely-accepted air dispersion modeling techniques." Second, she input these calculations into an air flow model endorsed by the U.S. Environmental Protection Agency called AERMOD to determine if Beachwood residents were exposed to particulates from fugitive dust emissions sources at the former BAC site. Third, she provided opinions re: whether, from 1969 to 1993, areas surrounding the BAC facility were exposed to elevated air concentrations of arsenic and hexavalent chromium.

Sears built her model by extrapolating data from chromium at the BAC site, in a treating solution that was released to the ground at the retort area where it entered the soil, and that this exposed solution in and on the soil was later disturbed by forklifts driving on the site. She offered the following opinions of exposures caused by the BAC facility wood storage area emissions:

(Doc. 781 at 5:21-6:9.)

Defendants move to exclude these opinions because her testimony rests on a number of unsupported assumptions about the chemical and physical properties of soils at the Site during the relevant time period (1969-1993). According to Defendants, Sears is unqualified to make these assumptions because she "is an atmospheric scientist and meteorologist, not an expert in chemistry, geology, geochemistry, or soil science." In addition, as part of her calculation of fugitive emissions, Sears allegedly employed an improper EPA emission technique, namely the paved road emission scenario (AP-42, § 13.2.1). The flawed assumptions, enumerated below, relate solely to Sears' "emission rate" calculations:

Defendants contend that these assumptions are demonstrably false and Sears does not have the expertise to make them. To support their Daubert motion, Defendants rely on the declaration and testimony of Dr. Paulo Zanetti, an air modeler, and Dr. Scott Fendorf, a chemist. Dr. Zanetti disputes Sears' use of the EPA's "paved road" emission scenario and, critically, the assumption that drippage would accumulate and remain on the surface of the wood storage area in the form of dust at a concentration of 900,000 parts per million. Dr. Fendorf opines that chromium does not drip off only in hexavalent state and, assuming it did, the chromium particles would be at least 100, not 10, microns in size.

Sears responds first to Defendants' claims that she is unqualified to calculate fugitive dust emissions from a wood processing facility:

(Doc. 785 at ¶ 15.)

On October 7, 2010, the second day of Daubert hearings, Sears testified that while she lacks formal "soil science" training, she has calculated air emissions in a number of environmental contamination cases and teaches a class in chemistry:

(RT, Oct. 7, 2010, 257:7-257:25.)

Ms. Sears detailed her experience calculating fugitive air emissions during counsel's direct examination on October 13, 2010. Ms. Sears' air emission experience, which is quite extensive and includes review of industrial sites and hexavalent chromium, rules out any characterization of her as "unqualified" in the field of calculating air emissions:

Now, as far as the Central Valley goes, I have calculated emissions from cooling towers. This was from a case where the emissions were in the past. And we calculated—or I calculated hexavalent chrome emissions. And then I modeled these emissions and calculated the air concentrations. And then we were also involved in looking at the background levels of hexavalent chromium in the central valley, basically in the '90s. Because that's when we had data. And so I've had quite a bit of experience looking at the data from the hexavalent chrome in the air from Stockton, Modesto, Fresno, Bakersfield, the site where the Air Resources Board was collecting this data in the 1990s.

(RT, Oct. 13, 2010, 560:12-567:4.)

Camille Sears is qualified to offer the testimony about how to calculate fugitive air emissions from a former wood-treatment facility. She has substantial experience in the air emission field, having calculated air emission rates for over twenty years in and around Northern and Central California. Sears has calculated fugitive air emissions for public and private employers and has experience with industrial sites and a variety of harmful pollutants, including hexavalent chromium. By education and experience, Ms. Sears is qualified to opine on air emissions, analysis and modeling in this case and her calculations can be challenged through cross-examination and presentation of contrary evidence. See Robinson v. GEICO General Ins. Co., 447 F.3d 1096, 1100 (8th Cir.2006) ("Gaps in an expert witness's qualifications or knowledge generally go to the weight of the witness's testimony, not its admissibility.").

Defendants take an overly-narrow view of the degree of expertise necessary to calculate fugitive air emissions in the context of air modeling. An air modeler, who is also an experienced atmospheric scientist and meteorologist, does not need to have a "sub-specialty" or advanced degree in chemistry or soil science before that person has sufficient qualifications to perform air emissions. Defendants cite no authority for such a proposition. Rather, Rule 702 only requires that an expert possess "knowledge, skill, experience, training, or education" sufficient to "assist" the trier of fact, which is "satisfied where expert testimony advances the trier of fact's understanding to any degree." See Lauria v. Nat'l R.R. Passenger Corp., 145 F.3d 593, 598 (3rd Cir.1998) (holding trial court abused its discretion by excluding testimony simply because the trial court did not deem proposed expert to be the best qualified or because proposed expert did not have the specialization that the trial court considered most appropriate); see also United States v. Newmont USA Ltd., No. CV-05-020-JLQ, 2007 WL 4856859, at *2 (E.D.Wash. Nov. 16, 2007) (in a mining enterprise case, holding that although the expert "is a historian, as opposed to an expert in the specific areas of `corporate organization' is not disqualifying in this case, as his background appears to provide sufficient expertise upon which his opinions, as a general matter, are based."). Ms. Sears has engaged in the field of air modeling and analysis as a regulator and expert for over twenty years. She has worked on sites that have toxic dust emissions. She satisfies Rule 702's foundational standards and her testimony will assist the trier of fact.29

Defendants next argue that Ms. Sears' entire emission scenario is flawed and lacks scientific reliability. According to Dr. Zanetti, Ms. Sears' flawed methodology begins and ends with her use of the "paved road" or "parking lot" emission scenario, AP-42 § 13.2.1. Dr. Zanetti opines that there is no scientific basis to model the paved portions at the BAC Site because they do not qualify as "roads." Rather, according to Dr. Zanetti, the proper emission scenario in this case is the EPA equation for unpaved surfaces. The selection of AP-42 as an emission scenario was fully developed during defense counsel's direct examination of Dr. Zanetti on October 14, 2010:

(RT, Oct. 14, 2010, 703:8-707:2.)

Dr. Zanetti argued that there was insufficient "road traffic" at the wood treatment area to support Ms. Sears' selection of the emission scenario for paved roads. He also argued that AP-42 explicitly states that the AP-42 formula should not be applied to "stop and go" traffic:

(RT, Oct. 14, 2010, 715:15-717:1.)

During counsel's re-direct examination on October 14, 2010, the fourth day of Daubert hearings, Ms. Sears testified that AP-42 is appropriate in these circumstances given the lack of an emission scenario for forklift use at industrial sites:

The fact that Ms. Sears used a different algorithm to calculate fugitive air emissions than Dr. Zanetti does not render her unqualified nor does it suggest her emissions scenario is invalid. Rather, based on the current record, her emissions scenario is relevant, admissible, and can be challenged through cross-examination and presentation of contrary evidence. In this Circuit, an expert's decision to use one form of scientific methodology over another goes to the expert's credibility rather than the admissibility of the testimony. See, e.g., United States v. Garcia, 7 F.3d 885, 889-90 (9th Cir.1993). This is such a case.

In addition, the Fed.R.Evid. 706 air experts, Drs. Countess and Cowherd, agree that there is a scientific basis to use AP-42 as an emission factor equation in this case. The relevant portion of the joint expert report provides, in relevant part:

(Doc. 942, pg. 12.)

Contrary to Defendants' contentions, the application of the "paved road" emission scenario was within Ms. Sears' realm of expertise as an air modeler and meteorologist. She has selected emission scenarios and calculated fugitive emissions for over twenty years. Ms. Sears has the expertise to use scientific judgment that AP-42 was the most accurate emission scenario for the former-BAC Site. This is especially true given the lack of a scientific algorithm designed explicitly for the types of industrial use and emission estimates required in this case. Dr. Zanetti's contention that only "unpaved surfaces" at the BAC site can be modeled is unreasonable given the 706 experts' contrary opinions. He offers no alternative to his unpaved model, citing only the "lack of scientific literature" to support Ms. Sears' AP42 emission scenario.30

The review of Sears and Zanetti's expert reports and deposition/hearing testimony, as well as the opinion of the Court's Fed. R.Evid. 706 experts, demonstrate that although the use of AP-42 to calculate fugitive emissions from the wood storage area of the former-BAC Site is sharply disputed, a disagreement over methodology is left to the adversary process and the trier of fact. The methodology here is not comparable to that found unreliable in In re Voluntary Purchasing Groups, Inc. Litigation, 2000 WL 1842779 (N.D.Tex.2000), a case excluding an air modeler's expert testimony under Rule 702 and Daubert.

Defendants' remaining arguments focus on the total mass calculation and the input parameters of Sears' model, i.e., drippage accumulation, the particle size, valence/purity of the contaminant and silt loading values. However, several of these inputs are functions Dr. Agardy's total mass calculation, which is not challenged and admissible:31

(Doc. 785, C. Sears Decl., at ¶ 50.)

The majority of Dr. Agardy's opinions are proper as they relate to the use of chemicals and chromium at the BAC site. These figures were a basis for Sears' model and are properly supported by Agardy's qualifications and expert reports. However, in his "new" declarations, (Docs. 782 & 955), Agardy opines on subject matter outside of his expertise: chemistry. Agardy is not qualified to opine on the conversion rates between Chromium III and Chromium VI. A review of his declaration reveals that Agardy simply quotes from several leading chemistry treatises and hornbooks, without establishing his own expertise to do so. Agardy's opinions on the chromium conversion are questionable. He is, however, qualified to opine on the total chromium mass at the former-BAC Site.

The final dispute concerns the scientific reliability of Sears' input parameters: the drippage accumulation; the silt loading values;32 the valence/purity of the contaminant;33 and the particle size (10 microns vs. 100 microns). Sears contends that her input parameters conform with well-recognized scientific principles. She asserts that the input parameter calculations are based on her scientific knowledge, experience and familiarity with air modeling, as well as a review and analysis of historical information at the BAC Site, Dr. Agardy's chromium drippage calculations, USEPA air pollution emission factors for paved roads, environmental and wind data from the site, and a review of pictures of the BAC Site and industrial vehicles used at the site. Defendants rejoin that these four input parameters lack scientific reliability and are inadmissible to generate a factual dispute.

Drs. Countess and Cowherd's Fed. R.Evid. 706 expert report provides a starting point to analyze the dispute over the input parameters. The Fed.R.Evid. 706 expert opinions are reproduced below, contrasted with the Daubert testimony of Ms. Sears. The expert report and opinions of Drs. Countess and Cowherd cast considerable doubt on Ms. Sears' silt loading, valence, accumulation and particle size inputs. Under Rule 702 and Daubert, however, the proper analysis is not whether some of the inputs can be questioned, but whether Sears' testimony is relevant and reliable, and whether the methods and principles upon which she has relied in forming her opinion have a sound basis in science. In this case, a comparison of the relevant expert opinions demonstrates a reasonable scientific dispute over input parameters and scientific principles.

First, Drs. Countess and Cowherd's independent expert report characterizes Sears' silt loading value as "seriously flawed":

(Doc. 942, pg. 15.)

On December 2, 2010, on direct examination, Sears explained that her silt loading values comported with "standard modeling practices":34

(Rough RT, Dec. 2, 2010, 173:14-175:1.)

With respect to the "accumulation" factor the Fed.R.Evid. 706 experts provide, in relevant part:

(Doc. 942, pg. 17.)

Although the one-year accumulation rate is allegedly unreasonable, Sears testified at the Daubert hearings that her figure was an "average" and that "it's going to vary from year to year":

(Rough RT, Dec. 2, 2010, 172:9-173:10.)

Drs. Countess and Cowherd also characterize Ms. Sears' particle size values as "seriously flawed":

(Doc. 942, pg. 15.)

With respect to Drs. Countess and Cowherd's particle size criticisms, Ms. Sears responds:

(Rough RT, Dec. 2, 2010, 176:2-179:5.)

Drs. Countess and Cowherd are critical of the assigned valence values:

(Doc. 942, pg. 18.)

Ms. Sears rejoined that her valence value conformed to scientific values and, in any event, the value "subject to an overall emission rate calculation uncertainty analysis" to account for variability:

(Rough RT, Dec. 2, 2010, 179:17-183:6.)

The comparison between the relevant expert opinions demonstrates that a reasonable scientific disagreement exists among the experts. Ms. Sears input parameters raise a host of serious concerns, but do not strip the model of all scientific reliability. See, e.g., Renaud v. Martin Marietta Corp., 749 F.Supp. 1545, 1552 (D.Colo.1990) ("Most of these alleged methodological flaws, however, must be considered by a jury when evaluating the weight to be given to the opinions, rather than by the Court in making the preliminary assessment concerning the admissibility of a given opinion.") (citations omitted). Such a dispute goes the credibility and the weight of the opinions, not admissibility.

Sears' allegedly flawed drippage accumulation calculation is illustrative. Defendants argue that Sears has no basis to given an opinion that a year's worth of drippage will accumulate at the surface; such a value contradicts reality as it assumes no disturbance or rainfall at the BAC site. On this point, Defendants submit the testimony of Dr. Fendorf, an expert in chromium and arsenic and a geochemist. Fendorf opines that hexavalent chromium is highly soluble in water and any significant rainfall dissolves hexavalent chromium at the surface and carries it into the soil.

Ms. Sears testified that the figure "is entirely reasonable" and supported by proper science, in addition to being an "average" accumulation rate. In this Circuit, the opposing party to a Rule 56 motion need not establish a material issue of fact conclusively in its favor. It is sufficient that "the claimed factual dispute be shown to require a jury or judge to resolve the parties' differing versions of the truth at trial." First Nat. Bank of Ariz. v. Cities Service Co., 391 U.S. 253, 290, 88 S.Ct. 1575, 20 L.Ed.2d 569; Hopper v. City of Pasco, 241 F.3d 1067, 1087 (9th Cir. 2001). A jury could consider the parties' competing expert testimony and reasonably conclude that chromium did not dissolve into the soil but stayed on the surface, reinforcing Sears' testimony (and her drippage calculation). The determination of the credibility and weight of the expert's conclusions should be reserved for the trier of fact.

The particle size dispute provides an additional example of a scientific factual dispute. Dr. Zanetti, an air modeler retained by Defendants, testified that the "five micron [size] [i]s not a problem," while Dr. Fendorf, another defense expert, stated in his declaration that "the chromium-arsenic salt particles that would be left behind by that evaporative process would not be in the size range that Ms. Sears assumes [...] [i]nstead, they would be sand-sized particles greater than 100 microns in diameter." (Doc. 722-1 at ¶ 5-7.) Drs. Cowherd and Countess provide yet another opinion, that it is "problematic to assume PM10 emissions can be represented as 5 micron particles in the dispersion process" because the PM10 emissions encompass a particle size range extending "from less than 1 micron up to 10 microns" and "the settling tendency of particles increase with particle size." In the scientific community, experts reach different conclusions from each other, however, reasonable differences in scientific evaluation are not a basis for exclusion. See Daubert I, 509 U.S. at 596, 113 S.Ct. 2786 ("[v]igorous cross-examination, presentation of contrary evidence, and careful instruction on the burden of proof are the traditional and appropriate means of attacking shaky but admissible evidence").

Having observed the experts at the Daubert hearing under intensive cross-examination by counsel, it is clear that the current dispute over Ms. Sears' calculations should be determined by the trier of fact, not by the Court on a motion to exclude. In re Scrap Metal Antitrust Litig., 527 F.3d 517, 529 (6th Cir.2008) (the "rejection of expert testimony is the exception rather than the rule.") (citation omitted). The decision to view Sears' differing analytical inputs as weaknesses in her analysis are a matter of weight rather than admissibility and thus properly a subject of argument and jury judgment. There is an insufficient showing of unreliability to exclude Ms. Sears' entire air model.

Finally, Defendants support their motion with a citation to air quality samples taken during excavation activities at the BAC site in 2007 and 2008. According to Defendants, Arcadis excavated the contaminated soil from the former retort area and installed four monitoring stations to detect any dust that might blow off the site during the excavation. Arcadis allegedly did not detect any chromium or arsenic-containing dust at the monitoring stations. This evidence, however, does not prove/disprove Sears' testimony concerning the air pathway for the years 1969-1993. Rather, it is one of many facts that may presented to the jury on the Phase 1 issue of whether soil contaminated with hexavalent chromium and/or arsenic was transported to Plaintiffs' homes or properties.

4. Risk Assessment (post-1993 years)

Plaintiffs claim that the 1994 Risk Assessment demonstrates that Plaintiffs in the Beachwood neighborhood were exposed to unacceptable airborne risk factors. Merck produced the Risk Assessment of the BAC site pursuant to an order from the California Department of Toxic Substances Control. Plaintiffs allege that the Risk Assessment satisfies their Phase 1 burden for the post-1993 years:

(Doc. 792 at 26:3-26:19.)

Plaintiffs do not respond to the Defendants' string citation of authorities holding that "risk assessments are intended to provide conservative estimates of risk and offer a wide margin of protection for human health [thus] federal courts have refused to accept their results as evidence of causation." See, e.g., Rhodes v. E.I. du Pont de Nemours and Co., 253 F.R.D. 365 (S.D.W.V.2008); see also Gates v. Rohm & Haas Co., 265 F.R.D. 208, 226 (E.D.Pa. 2010) (collecting cases).

In their motion for partial summary judgment, Defendants summarized the key portions 1994 Risk Assessment and the reasons why federal courts have excluded such risk assessments to demonstrate causation/exposure:

(Doc. 677-1 at 22:15-23:19.)

In Rhodes v. E.I. du Pont de Nemours and Co., 253 F.R.D. 365 (S.D.W.Va.2008) the court held that risk assessments were of "limited utility" in a toxic tort case based on the risk assessment's distinct regulatory purpose:

Id. at 377.

Rhodes concluded:

Id. at 378.

Rhodes' reasoning is sound. Here, the express purpose of the 1994 Risk Assessment was to provide a regulatory body, the DTSC, with conservative estimates of risk and provide a wide margin of protection for human health. It does not establish general exposure. It is not particularized nor does it include an identifiable risk of exposure to the Beachwood residents.

Plaintiffs have not provided any legal authority finding a Risk Assessment relevant to the issue of general exposure. Plaintiffs do not address the case law or why/how the Risk Assessment is relevant to prove actual causation to appreciable levels of contaminants from the BAC site. Under the reasoning of Rhodes and Gates v. Rohm & Haas Co., 265 F.R.D. 208 (E.D.Pa.2010), the motion for partial summary adjudication is GRANTED as to the 1994 Risk Assessment, which does not establish general exposure or otherwise satisfy Plaintiffs' Phase 1 burden as to the air pathway.

5. Conclusion on Air Pathway

The qualifications of Plaintiff's air model expert, Camille Sears, and the reliability of her methodology and assumptions are materially at issue in this case. Drawing all inferences in favor of the non-movant, Ms. Sears' testimony presents a scientific dispute not resolvable as a matter of law. Defendants' Daubert motion is DENIED and that portion seeking to adjudicate air contamination is also DENIED.

With respect to the 1994 Risk Assessment, Defendants' motion for partial summary judgment is GRANTED. The express purpose of the 1994 Risk Assessment was to provide a regulatory body, the DTSC, with conservative estimates of risk and a wide margin of protection for human health. It does not establish general exposure or otherwise satisfy Plaintiffs' Phase 1 burden as to the air pathway.

D. Pathway # 2—Groundwater/MWC-2

The parties' groundwater pathway arguments focus on whether contaminants from the BAC site reached Meadowbrook Well No. 2, the only well alleged to have been contaminated with chemicals from the BAC site. As explained above, scientific sampling was performed at MWC-2 by Meadowbrook Water District from 1964 to 2007. Monitoring was then performed by Arcadis, an environmental consultant (2007-2009). It is undisputed that MWC-2 was taken out of service in March 2008. A material dispute exists as to the reliability and accuracy of the sampling data from the network of monitoring wells35 and several extraction wells36 near the BAC Site.37

Plaintiffs offer the expert testimony of Douglas Bartlett, a hydrologist and groundwater modeler who opines that hexavalent chromium from the BAC Site entered and contaminated the water pumped by MWC-2 for at least a period of twenty-five years. According to Bartlett's groundwater model, hexavalent chromium reached the MWC-2 in mid-1972 in concentrations exceeding 10 ug/l. MWC-2's contamination levels allegedly increased between 1972 and 1994, reaching a peak value of 389 ug/l in June 1994. From that point on, according to Bartlett's model, hexavalent chromium concentrations decreased. Critical to satisfying the Phase 1 burden, Bartlett reports that hexavalent chromium was present in MWC-2 in excess of the federal (100 ug/l) and state (50 ug/l) Maximum Contaminant Level ("MCLs") for more than twenty years.

According to Defendants, Bartlett's testimony and groundwater model are inadmissible for a number of reasons but primarily because he excludes 46 years of sampling data (49 tests) from the MWC-2 and 16 years of sampling data from monitoring wells surrounding the BAC Site. Characterizing Bartlett's model as "contradicting reality," Defendants claim that Plaintiffs "have produced no data, documents, or percipient witness testimony that could establish exposure to hexavalent chromium or arsenic from the BAC Site through MWC-2 water, and the results of analyses of water from MWC-2 refute plaintiffs' claims that such exposure occurred." (Doc. 677-2 at 10:13-10:16.) Defendants assert that the actual testing data shows that total chromium concentration at MWC-2 never exceeded 12 ug/l, less than one quarter of the MCL for total chromium. Defendants also argue that MWC-2 never captured hexavalent chromium beyond background levels.

Defendants do not dispute that Bartlett is qualified to serve as an expert on groundwater modeling.38 Bartlett has been employed in the fields of hydrogeologic movement and soil investigation since 1977, focusing on groundwater contamination since 1984. Bartlett's employment history includes working as a consultant with Dames & Moore in Denver, Colorado from 1977 through 1989. In 1989, Bartlett moved to Phoenix, Arizona, where he managed several groundwater contamination projects for Dames & Moore. Several of these projects involved CERCLA remediation and groundwater modeling, including what is referred to as the "Motorola 52nd St. CERCLA site." In 1999, Bartlett left Dames & Moore to form the consulting firm "Clear Creek Associates." As a principal at Clear Creek, Bartlett provides groundwater modeling services to private and public entity clients throughout the United States.

According to his original and rebuttal reports, filed pursuant to Federal Rule 26(a)(2), Bartlett provides the following opinions: (1) the BAC Defendants' wood-treating operations introduced 12,913 pounds of hexavalent chromium to the groundwater over a twenty-five year period;39 (2) from the BAC site the hexavalent chromium migrated, pursuant to an established pathway, to MWC-2 and was extracted from that well with pumped water; and (3) Bartlett predicts that hexavalent chromium concentrations exceeded 50 ug/l in mid-1975 and peaked at 389 ug/l in June 1994.

Bartlett's relies heavily on the fact that his model is based on and derived from an earlier groundwater model developed by Arcadis, an environmental remediation firm contracted by Merck. According to Bartlett, the Arcadis' model evolved from a previous model created by IT Corp. in the 1990's. Arcadis, however, revised IT's model in the following ways: (1) expanded the model domain to include MWC-2 and nearby wells; (2) incorporated seasonal pumping from nearby production wells, including MWC-2 and Bernardo Dairy Well; (3) expanded the number of "well layers" to simulate various hydrogeologic strata at the site; and (4) hydraulic conductivity distribution was set in "uniform" layer mode based on slug tests, aquifer tests by Shaw, and specific capacity data. Arcadis ran the model in "steady-state" mode, which, according to Bartlett, is "essentially a point-in-time prediction rather than a prediction over a time period."

Bartlett's groundwater model makes a number of significant changes to the Arcadis model. According to Bartlett, these revisions were necessary because the "Arcadis model did not adequately simulate MWC-2 operations." Below is a summary of Bartlett's revisions and the reasons thereto:

Bartlett adopts several of Dr. Agardy's expert opinions to complete his chromium transport simulations. First, Bartlett acknowledges that other areas of the BAC Site may have contributed as chromium source origins, however, he adopts Dr. Agardy's opinion that the retort area was the primary source area. Second, Bartlett incorporates Dr. Agardy's opinion that a total of 12,913 pounds of chromium was released into the groundwater between 1969 and 1991, when the BAC facility closed. Bartlett then reports that the appropriate source of chromium in the groundwater model is based on the following factors: (1) hexavalent chromium was discharged at the surface and a portion was carried to groundwater by the natural infiltration of rainwater; (2) the hexavalent chromium required no more than one year to migrate to the water table; (3) the calculated total release of chromium occurred evenly between 1970 and June 1991; and (4) taking into account natural precipitation in the source area (1.14 inches x 22,500 sf = 16,000 gal/year). He also refutes Dr. El-Shoubary's "adsorption" theory, arguing that Dr. Argady's total chromium analysis takes into account any and all adsorption determinants.

BAC Defendants move to exclude Bartlett's testimony on grounds that his opinions ignore actual data in favor of unsupported modeling. They note that hexavalent chromium was measured 40 times in MWC-2 but never exceeded 2.5 micrograms per liter (ug/l or parts per billion) and that total chromium was measured 74 times but never exceeded 12 ug/l. In contrast, Bartlett's model predicts concentrations of hexavalent chromium up to 582 ug/l at MWC-2 during this same time period (1964 to 2009). BAC Defendants submit the following sampling from MWC-2, interposed with the relevant MCLs:

---------------------------------------------
   Date       Result    Cal MCL   Fed MCL
---------------------------------------------
   5/12/64    Trace     __        __
---------------------------------------------
   8/74       ND < 10   __        __
---------------------------------------------
   1/27/75    Trace     __        __
---------------------------------------------
   3/1/80     ND < 5    50 ug/l   50 ug/l
---------------------------------------------
   4/30/80    ND < 5    50 ug/l   50 ug/l
---------------------------------------------
   3/19/86    ND < 5    50 ug/l   50 ug/l
---------------------------------------------

   6/9/87     ND < 10   50 ug/l   50 ug/l
---------------------------------------------
   1/22/90    ND < 10   50 ug/l   50 ug/l
---------------------------------------------
   6/90       ND < 10   50 ug/l   50 ug/l
---------------------------------------------
   12/31/92   ND < 10   50 ug/l   100 ug/l
---------------------------------------------
   3/9/93     ND < 10   50 ug/l   ug/l
                           100
---------------------------------------------
   12/21/95   ND < 10   50 ug/l   ug/l
                           100
---------------------------------------------
   2/7/99     ND < 10   50 ug/l   100 ug/l
---------------------------------------------
   5/3/01     12.0      50 ug/l   100 ug/l
---------------------------------------------
   9/13/01    2.0       50 ug/l   100 ug/l
---------------------------------------------
   2/12/02    12.0      50 ug/l   100 ug/l
---------------------------------------------
   2/12/02    1.0       50 ug/l   100 ug/l
---------------------------------------------
   3/11/05    ND < 10   50 ug/l   100 ug/l
---------------------------------------------
   2/27/07    2.1       50 ug/l   100 ug/l
---------------------------------------------
   2/27/07    ND < 3    50 ug/l   100 ug/l
---------------------------------------------
   5/15/07    ND < 3    50 ug/l   100 ug/l
---------------------------------------------
   5/16/07    1.8       50 ug/l   100 ug/l
---------------------------------------------
   9/18/07    ND < 3    50 ug/l   100 ug/l
---------------------------------------------
   10/16/07   ND < 3    50 ug/l   100 ug/l
---------------------------------------------
   10/16/07   1.6       50 ug/l   100 ug/l
---------------------------------------------
   11/19/07   ND < 3    50 ug/l   100 ug/l
---------------------------------------------
   12/18/07   ND < 3    50 ug/l   100 ug/l
---------------------------------------------
   1/16/08    ND < 3    50 ug/l   100 ug/l
---------------------------------------------
   2/22/08    ND < 3    50 ug/l   100 ug/l
---------------------------------------------
   3/21/08    ND < 3    50 ug/l   100 ug/l
---------------------------------------------
   5/29/08    ND < 3    50 ug/l   100 ug/l
---------------------------------------------
   6/30/08    ND < 3    50 ug/l   100 ug/l
---------------------------------------------
   7/30/08    ND < 3    50 ug/l   100 ug/l
---------------------------------------------
   8/20/08    ND < 3    50 ug/l   100 ug/l
---------------------------------------------
   9/18/08    ND < 3    50 ug/l   100 ug/l
---------------------------------------------
   10/23/08   ND < 3    50 ug/l   100 ug/l
---------------------------------------------
   11/21/08   ND < 3    50 ug/l   100 ug/l
---------------------------------------------
   12/23/08   ND < 3    50 ug/l   100 ug/l
---------------------------------------------
   1/09/09    1.8       50 ug/l   100 ug/l
---------------------------------------------
   1/20/09    ND < 3    50 ug/l   100 ug/l
---------------------------------------------
   3/19/09    ND < 3    50 ug/l   100 ug/l
---------------------------------------------
   8/06/09    ND < 10   50 ug/l   100 ug/l
---------------------------------------------
   8/11/09    2.3       50 ug/l   100 ug/l
---------------------------------------------
   8/18/09    2.5       50 ug/l   100 ug/l
---------------------------------------------
   8/25/09    2.1       50 ug/l   100 ug/l
---------------------------------------------
   9/1/09     1.8       50 ug/l   100 ug/l
---------------------------------------------
   9/08/09    1.9       50 ug/l   100 ug/l
---------------------------------------------
   9/15/09    2.2       50 ug/l   100 ug/l
---------------------------------------------
   9/22/09    1.8       50 ug/l   100 ug/l
---------------------------------------------

In their motion, BAC Defendants raise a number of specific objections to Bartlett's justifications for excluding the historic sampling data from his groundwater model. BAC Defendants' objections, which are supported by the expert declarations of Daniel B. Stephens and John L. Wilson, are summarized as follows:

BAC Defendants rely on the opinions and modeling of Daniel B. Stephens and John L. Wilson to challenge Bartlett's testimony. Stephens and Wilson believe, based on their model and observed conditions, that chromium contamination from the BAC site did not reach MWC-2. Their model predictions are inconsistent with Bartlett's model, which Wilson characterizes as "invalid" and violating the basic premise of expert modeling: merging existing data with model assumptions. As to Bartlett's critiques of and modifications to the Stephens/Wilson model, Wilson responds:

(Doc. 677-7 at ¶¶ 6-7.)

Daniel B. Stephens' declaration, supporting BAC Defendants' motion for summary judgment, mirrors the positions taken by Mr. Wilson in his declaration. (Doc. 697 at ¶¶ 4-15.)

Plaintiffs dispute BAC Defendants' characterization of Bartlett's modeling and his decision to exclude the sampling at and around the BAC Site, including MWC-2's sampling data. In opposing BAC Defendants' motion and expert arguments, Bartlett declares that his model "incorporated the work of other Merck consultants and was based on sound, state-of-the-science analysis." He also reaffirms his original position that MWC-2 was contaminated with concentrations of chromium in excess of the MCL for a period of twenty-five years.

Bartlett's 23-page declaration, an extension of Plaintiffs' 36-page opposition brief, focuses on the decision to exclude the sampling data as an input into his groundwater model. Bartlett declares that the sampling was disregarded for the following reasons: (1) the samples "appear to be taken" during periods of low pumping; (2) lack of documentation concerning how the samples were collected; (3) the deeper portions of the well were not screened; and (4) the pulsating nature of the chromium movement combined with the fact that, since 1993, regional groundwater flow is to the northwest. These criticisms are not made in Bartlett's original expert report, submitted to the BAC Defendants on December 9, 2009.

Bartlett's supplemental declaration repeats his criticisms of the Wilson/Stephens groundwater model. Specifically, Bartlett theorizes that chromium travels much more rapidly in the aquifer than either model anticipates and that the monitoring system did/does not adequately sample the deep portion of the aquifer:

(Doc. 777 at ¶ 8.)

This is puzzling in view of Bartlett's hearing testimony that the source of contamination is not from the deep aquifer below 140 feet, but rather is in the shallow aquifer.

According to Bartlett, the Wilson/Stephens model "does not simulate what has been observed at the BAC site." Bartlett specifically cites sampling from offsite well M & A-1 in July 1992, which measured 1,300 ug/l.40 The Wilson/Stephens model predicted less than 6 ug/l. As to the most critical area, MWC-2, Bartlett argues that the model under-predicts chromium contamination and "[Wilson] should apply his criticism of the Bartlett Model to his own model."

Bartlett's supplemental declaration purports to reinforce the scientific basis for his model and the exclusion of MWC-2's sampling data. According to Bartlett, the historical operation and construction of MWC-2 is not sufficiently documented to allow for scientifically-accurate groundwater (and flow) modeling. Bartlett also responds to Stephens' criticisms concerning "background concentrations of chromium in regional groundwater." Given the importance of chromium background concentrations to the instant inquiry, the relevant portion of Bartlett's supplemental declaration is reproduced in its entirety:

(Doc. 777 at ¶¶ 11-12.)

The BAC Defendants, in their reply, assert that there is an unexplained analytical gap between Bartlett's model and the actual data. Defendants argue that there is no evidence of low-pumping at MWC-2, rather there were several months where the well pumped more than 20 million gallons (above average); that "pulse" movements cannot explain nearly 46 years of near non-detect results; Bartlett's theory that the monitoring wells are too shallow to detect the hexavalent chromium plume is wrong because he predicts high concentrations at depth and in the shallow zone; testing of the "deep" wells near the BAC site—DW-1 and DW-2—were non-detect when sampled in 1991 and 1992. Bartlett's model, however, predicts chromium concentrations in excess of 5,000 ug/l at those wells, contrary to the actual sampling. At the hearing, Bartlett rationalized the differences by opining that data from the monitoring wells failed to detect chromium in the shallow aquifer, presumably at 60 to 150 ft bgs.

Defendants' final reply argument is that even assuming, arguendo, that there is a valid scientific objection to the pre-2007 sampling data, Plaintiffs fail to reconcile Bartlett's groundwater model with: (1) post-2007 MWC-2 data; and (2) the data from the BAC Defendants' monitoring well network. Bartlett's model is contrary to almost all observed data, California Department of Public Health statutes and test results, and DTSC findings after remediation efforts, all of which concluded hexavalent chromium was not present at levels in excess of the MCL.

Based on the magnitude of the dispute between the parties' experts and the complexity of the groundwater issues in this case, the Court retained, under Fed. R.Evid. 706, an independent expert, geohydrologist Kenneth D. Schmidt, Ph.D., to assist in the understanding and analyzing the dispute in the groundwater pathway issues.41 Dr. Schmidt's expert report, submitted on November 22, 2010, disagrees with Mr. Bartlett's model. The substantive divergence being Schmidt's opinion that a substantial relatively impermeable clay layer—the "Corcoran clay"—exists beneath MWC-2 (and other wells near the BAC site) at approximately 92 feet.42 Based on his review of the original well driller's log, the electronic logs ("e-logs") and his extensive professional experience working in the Merced area and Central Valley geohydrology, Dr. Schmidt believes that MWC-2 is an open-bottomed well, with a "blank casing" landed in the clay layer (at approximately 92 feet).43 The impact and effect of these conditions is that MWC-2 primarily drew uncontaminated water the deep aquifer below the Corcoran clay layer, not the upper aquifer, i.e., there is minimal hydraulic connectivity between the upper and lower aquifers. Because Bartlett believes that the upper aquifer is contaminated, Dr. Schmidt's conflicting opinion puts in material the "source and extent of contamination" in MWC-2.

Bartlett vehemently disagrees. In his testimony on December 15 and 28, 2010, he testified that MWC-2 primarily drew water from the upper aquifer above the non-continuous clay layer. Bartlett contends that there is no evidence of an "annular seal" in the 2009 video log or, separately, the gamma ray log.44 Because there is no annular seal and slots in the well's casing, water from the upper aquifer flowed into the well, i.e., there was nothing to prevent the downward flow of contaminated water. It is Bartlett's opinion that the water pumped at MWC-2 contained contaminated water from the upper aquifer. This opinion is contrary to Dr. Schmidt's independent expert report.

Dr. Schmidt offers a number of additional contrary opinions to support his conclusion that Bartlett's model is unreliable and inaccurate:

(Doc. 941 at pgs. 4-25.)

Dr. Schmidt's ultimate opinion is that "the Bartlett model cannot be used to determine the historical chromium concentrations in water pumped from MWC-2." (Id. at pg. 25.) According to Dr. Schmidt, his opinion was based on a number of factors, but "primarily [] due to [] the use of values for hydraulic conductivity that are too high [and] the assumption of too much water from above the Corcoran Clay being pumped from MWC-2." (Id.)

Dr. Schmidt's opinions were the focus of argument and testimony on December 3, 15, and 28, 2010, at which time Bartlett presented rebuttal testimony. Bartlett opined that Dr. Schmidt's opinions were incorrect and reiterated that there was no evidence of an annulus seal, i.e., there was groundwater movement between the upper and lower aquifers at MWC-2 (MWC-2 primarily drew water from the contaminated upper aquifer). During his testimony, Bartlett played portions of the 2009 video log, pausing the video to provide commentary at critical points. Bartlett noted that at 92.8 feet bgs he observed the actual bedrock (alluvial formation) outside of the steel casing, evidence of an absence of a casing. Bartlett also observed a number of corrosion holes in the steel casing, which allegedly allowed the water to move freely from the upper aquifer.46

With respect to the presence of a clay layer, Bartlett opined that no layer exists because, at 98.4 feet, "I can look through the casing and see if there is no seal. There is a bore hole wall. And quite a large gap, probably several inches." (RT, Dec. 15, 2010, 23:3-23:5.) Bartlett also argued that the gamma ray log supported the lack of a continuous and thick clay layer beneath MWC-2. Whether a "substantial" continuous clay layer exists beneath at MWC-2 is heavily disputed between Dr. Schmidt and Mr. Bartlett.

With these parameters of the dispute, the parties' arguments are addressed in the context of Federal Rule of Evidence 702 and the Supreme Court's decisions in Daubert, 509 U.S. 579, 113 S.Ct. 2786, 125 L.Ed.2d 469, and Kumho Tire Co., 526 U.S. 137, 119 S.Ct. 1167, 143 L.Ed.2d 238.

1. Bartlett Groundwater Model—In or Out?

The seminal dispute between the parties is whether Bartlett properly excluded the MWC-2 and monitoring well data from his groundwater model. Plaintiffs state that the BAC defendants' Daubert motion is fundamentally improper because they are challenging the "results" of the model, not the methodology. According to Plaintiff, such a challenge falls outside Daubert's ambit and must be determined by the trier of fact. Plaintiffs further argue that the sampling data and any model excluding that data are not necessarily inconsistent. Rather, "defendants have cited to no authority that somehow such data trumps expert opinion on these issues or that such data is required in addition to expert opinion and analysis in order for plaintiffs to meet their burden at trial":

(Doc. 776 at 2:16-2:22.)

Defendants rejoin that they are not challenging Bartlett's conclusions per se, rather they dispute the inconsistencies between Bartlett's model and the actual sampling data. According to Defendants, Bartlett's model is inherently unreliable because: (1) his model contradicts and ignores all of available field testing data; (2) Bartlett developed his model without reviewing the data and then, when it was brought to his attention, simply ignored the data; (3) Bartlett's model departs from well-recognized groundwater modeling protocol because it is not calibrated to actual well monitoring data; and (4) Bartlett failed to perform a sensitivity analysis on his model, another breach of well-recognized modeling protocol. These reasons allegedly disqualify Bartlett's model under Rule 702 and Daubert.

Citing Ramsey v. Consolidated Rail Corp., 111 F.Supp.2d 1030, 1037 (N.D.Ind. 2000), and In re TMI Litigation, 193 F.3d 613, 671 (3d Cir.1999), amended on other grounds, 199 F.3d 158 (3d Cir.), cert. denied, 530 U.S. 1225, 120 S.Ct. 2238, 147 L.Ed.2d 266 (2000), BAC Defendants argue that "[m]odel-based opinions are of no value to a trier of fact where they are contrary to real world data." In Ramsey, the court framed the relevant legal inquiry as follows: "The issue before the court isn't whether Dr. Haitjema's [Plaintiff's groundwater expert] analysis is more probably correct than incorrect—the Ramseys are entitled to have that issue decided by a jury rather than a judge—but rather whether the opinion testimony that encompasses his analysis is admissible into evidence."

Ramsey's facts and reasoning provide a starting point.47 In Ramsey, Plaintiffs attempted to rely on groundwater modeling to prove groundwater contamination. Specifically, Plaintiff attempted to demonstrate that TCE contamination from a rail yard migrated north to Plaintiffs' off-site well. Plaintiffs' well was tested twice during the relevant time-frame, and no contamination was found. Additionally, two upgradient wells (between the rail yard and well) were similarly negative for contamination. The Ramsey court stated that the upgradient wells had been sampled twelve times, and no contamination had been found in any of those wells.

The Ramsey Plaintiffs submitted the testimony of Dr. Haitjema, who opined that groundwater modeling demonstrated that contamination reached the Plaintiffs' well during the years 1983 to 1998. Dr. Haitjema's model directly conflicted with sampling results, and Defendants moved to strike the testimony under Daubert. In response to Defendants' motion, Dr. Haitjema argued that his model was valid because: (1) groundwater contamination provides a "snapshot of contaminant occurrences" and is inherently unreliable because contaminants "move along different pathways at different rates and at different times."; (2) his model incorporated an EPA consultant's model, who was retained at an earlier time to investigate possible contamination near the rail yard; (3) the allegedly contaminated well tapped from the same depth as a contaminated well to the south (towards a rail yard); and (4) contamination from the rail yard would vary spatially and temporally.

Ramsey decided that none of Dr. Haitjema's arguments established the reliability of his model or the opinion that appreciable rates of TCE reached the Plaintiffs' well. The Court held that although Dr. Haitjema's methodology passes the Daubert inquiry with "flying colors," the "record identifies no scientific principle on which Dr. Haitjema based the critical last step of his analysis—that the uniform `non-detect' results of well testing, not only of the Ramseys' well but also wells to the south, don't affect the conclusion that TCE [] from the rail yard entered the Ramsey's drinking water." The Court further explained the basis for excluding Dr. Haitjema's model under Daubert:

Id. at 1037.

The Ramsey court concluded:

Id. at 1037-38.

Ramsey has facial similarity to this case: the expert argued that his "methodology is well-accepted in the [groundwater] field" and that "other modeling studies support his conclusions about the general directions of groundwater movement [around the site]." Id. at 1034. Similarly, Bartlett argues that the MODFLOW methodology is well-accepted in the field, which it is,48 and that the Arcadis model supports the general directional movement, which it generally does. As demonstrated by the Ramsey opinion, however, allegiance to portions of accepted scientific protocols, but not others, is not dispositive of the Daubert inquiry. The Third Circuit explains: "[u]nder Daubert, any step that renders the expert's analysis unreliable [. . .] renders the testimony inadmissible [. . .] [t]his is true whether the step completely changes a reliable methodology or merely misapplies that methodology." Mitchell v. Gencorp Inc., 165 F.3d 778, 782 (10th Cir.1999). Bartlett's model is on the razor's edge of that standard. He has now offered explanations why the testing results are not reliable: (1) the monitoring wells are too shallow and do not intercept the contaminated aquifer; (2) groundwater reliability is not accounted for; (3) test methods and test results are suspect and not objectively confirmable; and (4) there is infrequent testing of MWC-2.

The comparisons between this case and Ramsey do not end there. The Ramsey expert justified his model's predictions, accepting the non-detect field data, by opining that the "degree of groundwater contamination downgradient from the rail yard [] would vary spatially and temporally," and "in nearly every case in which he ha[d] been involved, `discrepancies' have been found between expected pathways of contaminants and data from wells." Id. Plaintiffs in this case similarly state: hexavalent chromium is so chemically unbalanced and unstable (and subject to pulses) that it cannot be tested; and the data is unreliable due to pumping irregularities and variability; and inadequate documentation by Meadowbrook. Assuming, arguendo, that those criticisms have merit, there is a scientific, practical, and logical expectation that at least one of the data points from MWC-2—from the years 1964 to 2009—would have been positive for hexavalent chromium, if Bartlett's model was reliable and accurate. Borrowing from Ramsey's language: "[the Court] struggles to avoid the superficially logical conclusion" that hexavalent chromium would have been detected at MWC-2, at actionable levels, at least one time during the relevant time period.

During oral argument on December 29, 2010, Plaintiffs' counsel sought to distinguish Ramsey by stating that Ramsey only dealt with "true non-detects." In this case, there are many (many) MWC-2 and test well non-detects significantly lower than the MCL (3-10 ug/l). There is, however: (1) data from the early 1990's that other, more distant wells—extraction and monitoring—were more contaminated; and (2) a 2008 sample from MW-23 shows a high chromium hit of 450 ppb. Plaintiffs reason that Ramsey is distinguishable based on the "`true' non-detect" nature of the sampling data; a single reading above non-detect level deprives the case of any analogous impact.49

To understand this argument it is necessary to profile the observed data from MWC-2 and the monitoring/extraction wells and, more importantly, describe how it was analyzed/used during the different stages of Plaintiffs' case, i.e., first in the expert reports, second, in summary judgment declarations, and last, in the post-trial hearings (Daubert and rebuttal to 706 experts). A close review of these documents and testimony reveals several inaccuracies and/or unexplained assertions in the Bartlett model (and his testimony). Such a determination, however, is inherently based on credibility, which is the function of the trier of fact.

Bartlett testifies in December 2010 that he did consider all of the test data. Defendants argue that Bartlett's minimization of this data necessarily raises the question whether the Bartlett model was "calibrated" and tested according to well-established modeling protocol. The consideration of the MWC-2 and monitoring/extraction well data is considered in the context of the calibration arguments.

According to well-recognized groundwater modeling principles and the undisputed expert testimony in this case, an expert must test or "calibrate" a model to align the model predictions with field observations.50 See, e.g., Mary P. Anderson and William W. Woessner, "Applied Groundwater Modeling: Simulation of Flow and Advective Transport." According to this treatise, among others, the larger the disconnect, the greater need to validate or "calibrate" the groundwater model. As explained by one federal district court, "[c]alibration is the adjustment of parameters of a model's geometry or input parameter values in an effort to match model outputs to observed conditions." Chitayat v. Vanderbilt Assoc.'s, No.03-5314-DRHMLO, 2007 WL 2890248, at *3 (E.D.N.Y. Sept. 27, 2007).

Defense counsel's direct examination of Dr. Stephens on October 6, 2010 provides a starting point to analyze whether Bartlett's model employs flawed methodology, specifically, whether Bartlett improperly excluded/ignored relevant field data so that his model "predicted" higher concentrations of hexavalent chromium at MWC-2. Stephens believes that Bartlett omitted, without scientific justification, several fundamental modeling steps that are built into the modeling protocol to ensure scientific reliability:51

(RT, Oct. 6, 2010, 124:20-129:9.)

Defendants argue that Bartlett, armed with this knowledge and without scientific justification, elected not to "test" his model against field data revealing an absence of hexavalent chromium at or near MWC-2. The result, according to Defendants, is a model and opinion that is inherently unreliable and only connected to existing data "by the ipse dixit of the expert." See Joiner, 522 U.S. at 146, 118 S.Ct. 512.52

Plaintiffs suggest that Bartlett's model conforms to well-recognized groundwater methodology because he calibrated the "flow" portion of his model and, critically, used his "professional judgment" to exclude chromium concentration data from MWC-2 and the monitoring wells, i.e., the "transport" component.

Bartlett's model consisted of two components: "flow" and "transport." The "flow" portion models groundwater flow in saturated and unsaturated zones around the target site, including confined, unconfined and perched aquifers. The "transport" portion models the supply or source of the chemical to groundwater, focusing on mass per unit of time (entering the groundwater). The flow and transport components work synergistically to assist the modeler in estimating whether a contaminant entered the groundwater table and, if so, whether the contamination migrated from the source to off-site locations.

Plaintiffs' argument has some support in the record. They rely on the Anderson and Woessner treatise which annotates the calibration, calibration sensitivity analysis, and model verification steps as follows:

While Bartlett specifically delineated "field-measured heads and flows,"53 there is no mention of calibrating the "transport" portion of the model to observed concentrations of contaminants from specific wells or monitoring well networks. However, according to the California EPA's groundwater investigation manual,54 titled "Ground Water Modeling for Hydrogeologic Characterization," both the flow and transport components of the model must be calibrated to field data:

California EPA, Ground Water Modeling for Hydrogeologic Characterization (Oct. 15, 2010, 9:35 p.m.), http://www.dtsc. ca.gov/SiteCleanup/upload/SMP_Groundwater_Modeling.pdf.

Although these two authoritative sources do not provide a definitive answer on the issue of "calibration," i.e., whether well-established groundwater modeling protocol requires an identical calibration of the "transport" and "flow" models, it is undisputable that calibration is a "critical" and "valuable" step that ensures that model simulation matches the field observation to a reasonable degree.55

Defendants focus on Bartlett's evolving rationalization for his approach to "testing" the transport portion of the groundwater model, originally excluding all of the data from MWC-2 data and monitoring well network.56 Defendant are correct that Bartlett's current position is not completely consistent with his expert report or his deposition testimony. Although Bartlett's testimony is contradicted in some respects, the credibility of a witness is an issue for the jury. See, e.g., Bourns, Inc. v. Raychem Corp., 331 F.3d 704, 714 (9th Cir.2003).

For instance, in his expert report, submitted on December 9, 2009, Bartlett devotes more than twenty-four pages to his revisions of the Arcadis model. The "model calibration" section spans nineteen lines and is limited to a discussion of the "flow" component:

(Doc. 777-2, Bartlett Export Report, pgs. 25-26.)

Missing from the this discussion, headed "Model Calibration," is any mention of calibrating the "transport" portion of the groundwater model or any reason not to calibrate it.57 In addition, under the "Results" section, Bartlett states:

(Id. at pg. 32.)

Notably absent from these two sections, and the entire expert report, is any mention of the MWC-2 data from the years 1964-2007. Not one sample is mentioned. There is also no indication in the report that the MWC-2 sampling data was deficient because of infrequent testing, poor record-keeping, pumping irregularities, flow variations, or human error. These observations were only identified by Bartlett over three days of testimony in the Fed.R.Evid. 104 hearing. In view of the importance of the MWC-2 data to this model's reliability and whether contamination reached MWC-2's lower aquifer, these initial omissions — and lack of explanation — raise material credibility issues.58

Two additional concerns are raised by the omission of the MWC-2 data from Bartlett's expert report that impact his credibility but do not exclude his testimony under Daubert. One, Defendants assert that the MWC-2 data was not mentioned in the expert report because Plaintiffs' counsel did not make the data available to Bartlett prior to building his model or, alternatively, he received the data but did not review it prior to modeling.59 Defendants maintain that such oversight invalidates the groundwater model. Two, Bartlett's reliance on the water level data from the California Department of Water Resources and the U.S. Geological Survey — to calibrate the "flow" component —, conflicts with his later assertion (after the expert report) that the MWC-2 sampling data is unreliable because it lacks "chain of custody" documentation. Chain of custody evidence is a legal inquiry relevant to authenticity of underlying subject matter. Normally it goes to weight not admissibility of evidence.

Bartlett's alleged lack of awareness of the MWC-2 data was developed during cross-examination on October 7, 2010:

(RT, Oct. 7, 2010, 168:15-173:9) (objections omitted)

In this Circuit, Bartlett's deposition and court testimony are subject to impeachment, not exclusion. Assessing the credibility of a witness is properly left to the jury. Whether Mr. Bartlett did not receive or consider the data is a disputed fact based on Mr. Bartlett's assertion that the data was received and reviewed by his staff and considered in relation to the model's formulation. Mr. Bartlett testified he knew that municipal wells underwent extensive testing and public compliance regulation, but he did not personally analyze/review the data prior to his model's completion. Nor was the data an any reason for excluding it mentioned in his expert report. The reasonableness of Mr. Bartlett's handling of the data ultimately present credibility issues for the jury.

The second area is Mr. Bartlett's review of and reliance on the water level data from the California Department of Water Resources and the USGS. According to his expert report, Bartlett used this data to calibrate the "flow" component of his groundwater model. (Doc. 777-2, pgs. 25-26.) Specifically, during oral argument on October 7, 2010, Bartlett explained that he calibrated his flow model with sampling data from the California Department of Water Resources and the USGS:

(RT, Oct. 7, 2010, 397:1-397:15.)

This data was downloaded from the internet without any foundational or chain-of-custody documents. Bartlett now claims that the MWC-2 sampling data is unreliable because it lacks the same foundational support:

(RT, Oct. 7, 2010, 420:8-423:18)

Although Bartlett now argues that the MWC-2 data lacks the requisite foundation, he fully accepts the water level data without knowing anything about the foundation for that data. Bartlett offered little explanation why he distrusts the State of California water quality test data for MWC-2. There is a similar lack of clarity or justification why Bartlett calibrated the "flow" component of the groundwater model but not the "transport" component.60

The next dispute is whether Bartlett's selective use and/or exclusion of monitoring and extraction well data invalidates the groundwater model. On December 28, 2010, Plaintiffs introduced Exhibit No. 11, a catalogue of citations to the December 15, 2010 testimony to support their groundwater arguments, in response to the Dr. Schmidt's independent expert report. On the monitoring/extraction well dispute, this document provides, in relevant part:

(Pl.'s Exhibit No. 11, Dec. 28, 2010, 3:22-4:11.)

On December 28, 2010, Bartlett explained that the true problem in this case is the "misleading" monitoring well network. It is Bartlett's position that the contaminated water is "below" the monitoring well network, i.e., the monitoring wells screen at shallow depths:

(Rough RT, Dec. 28, 2010, 72:19-73:2.)

Bartlett, however, supports his model predictions with the citations to these same "shallow" monitoring wells. In particular, he relies on the "high hits" from MW-23 and MW-24 in June 2008 to establish the presence of chromium contamination in MWC-2 in 2008 (and prior to 2008).61 He also relies heavily on data from a number of extractions wells near the BAC site, over 1,000 feet away from MWC-2:

(Id. at 66:9-66:16.)

Bartlett further explained the impact of the MW-23 and MW-24 "high hits" on his model:

(Id. at 71:1-71:6.)

Defendants, however, contend that this is one example of Bartlett's "selective" incorporation of observed monitoring well data, i.e., he incorporates the few data points that "fit" his model predictions to the exclusion of all others. Any data that is inconsistent with his model predictions is excluded based on his "professional judgment." MW-23 is illustrative of this criticism. As explained, Bartlett specifically relies on the 450 ppb sampling in June 2008, which Dr. Schmidt testified was an outlier, and excludes the (many) non-detect chromium observations at MW-23 (before and after June 2008):

________________________________
     DATE        RESULT
--------------------------------
  March 1994      < 10
--------------------------------
  June 1994       14.9 T
--------------------------------
  July 1994       12.8
--------------------------------
  August 1994     8.1
--------------------------------
  Oct 1994        4.8
--------------------------------
  Nov 1994        <3
--------------------------------
  Dec 1994        5.4
--------------------------------
  Feb 1995        3.1
--------------------------------
  April 1995      < 3
--------------------------------
  July 1995       7
--------------------------------
  Oct 1995        < 3
--------------------------------
  Jan 1996        3.1
--------------------------------
  April 1996      3.2
--------------------------------
  July 1996       < 3
--------------------------------
  Oct 1996        < 3
--------------------------------
  Jan 1997        < 3
--------------------------------
  April 1997      < 3
--------------------------------
  July 1997       < 3
--------------------------------
  Oct 1997        < 3
--------------------------------
  Jan 1998        < 3
--------------------------------
  April 1998      < 3
--------------------------------
  August 1998     < 3
--------------------------------
  Oct 1998        < 3
--------------------------------
  Jan 1999        < 3
--------------------------------
  April 1999      < 3
--------------------------------
  July 1999       < 3
--------------------------------
  Oct 1999        < 3
--------------------------------
  Jan 2000        < 3
--------------------------------
  Apr 2000        < 3
--------------------------------
  July 2000       < 3
--------------------------------
  Oct 2000        < 3
--------------------------------
  Jan 2001        < 3
--------------------------------
  April 2001      3.9
--------------------------------
  August 2001     < 3
--------------------------------
  Oct 2001        < 3
--------------------------------
  Jan 2002        < 3
--------------------------------
  April 2002      < 3
--------------------------------
  July 2002       < 3
--------------------------------
  Nov 2002        < 3
--------------------------------
  Jan 2003        < 3
--------------------------------
  May 2003        3.7
--------------------------------
  Sep 2003        3.6
--------------------------------
  Nov 2003        < 3
--------------------------------
  Feb 2004        < 3
--------------------------------
  April 2004      < 3
--------------------------------
  July 2004       < 3
--------------------------------
  Oct 2004        < 3
--------------------------------
  Jan 2005        3.5
--------------------------------

  May 2005        < 3
--------------------------------
  August 2005     4.1
--------------------------------
  Nov 2005        4.3
--------------------------------
  Feb 2006        1.9 J
--------------------------------
  May 2006        2.3 J
--------------------------------
  Nov 2006        2.2 J
--------------------------------
  August 2007     < 3
--------------------------------
  Sep 2007        < 3
--------------------------------
  Oct 2007        < 3
--------------------------------
  Nov 2007        3.8
--------------------------------
  Dec 2007        < 3
--------------------------------
  Jan 2008        < 3
--------------------------------
  Feb 2008        < 3
--------------------------------
  March 2008      < 3
--------------------------------
  Jun 2008        450
--------------------------------
  July 2008       53
--------------------------------
  Aug 2008        9.5
--------------------------------
  Sep 2008        6.2
--------------------------------
  Nov 2008(7)     2.0 (hex)
--------------------------------
  Nov 2008(24)    8.2
--------------------------------
  Dec 2008        18
--------------------------------

Bartlett opines that the "spike" of 450 ppb in June 2008 was a result of the MWC-2's being taken off-line, i.e., the cessation of pumping activities at MWC-2 increased the water levels in MW-23 and other monitoring wells so that the chromium plume was fully present in the first layer (50 feet bgs). However, the abeyance of pumping at MWC-2 does not fully address the inquiry in view of: (1) MW-23 was screened to approximately 58 feet bgs (chromium should be present in portions of the second layer); (2) the low chromium observations in August, September, November, and December 2008; and (3) there were periods of low pumping at MWC-2 prior to June 2008, however, there was not a single observation above actionable levels (specifically, above 14.9 total chromium).

Despite the arguments to the contrary, Bartlett's opinions concerning the monitoring well network represent a factual scientific dispute to be determined by a jury. If Bartlett is to be believed, the monitoring well network was too shallow; the network screened the upper well, missing the chromium contaminations present in the lower layers. Although less persuasive, Bartlett states that the MWC-2's being taken off-line in March 2008 allowed the actual chromium contamination to be observed at monitoring well depths in June 2008. The present showing is marginal to demonstrate that the monitoring well data is "misleading" or otherwise scientifically objectionable (and not considered). At trial, Plaintiffs must demonstrate clear scientific justification to omit the monitoring well data, including the fourteen years of non-detects (1994 to 2008) and the restoration of low chromium observations at MW-23 immediately following the June 2008 hit. If such evidence is not developed, Mr. Bartlett's testimony is subject to the Court's reserved authority to strike it under Fed.R.Evid. Rules 104, 203, 206, 403, and 702.

The same scrutiny applies to the decision not to calibrate or "test" the model predictions to the field data from MWC-2, which reveal non-detect chromium levels for thirty years. Although the BAC Defendant's Daubert motion is denied without prejudice, subject to a reservation to strike the testimony at trial, Mr. Bartlett, on December 28, 2010, clarified that in his professional judgment the MWC-2 data was unreliable based on its infrequency, not chain of custody or other foundational deficiencies. His December 28, 2010 testimony raised a second concern, that the model is barred under Daubert's reliability prong because there is an absence of a known or potential rate of error:62

(Rough RT, Dec. 28, 2010, 176:7-179:21.)

Although a close call, a scientific factual dispute remains whether the MWC-2 field data is a true reflection of chromium concentrations at MWC-2 during the relevant time-frame. According to Bartlett, he "considered" the MWC-2 field data, but ultimately concluded it was unreliable based on testing infrequency. The BAC Defendants point out that these alleged justifications were absent from his expert report and conflict with his deposition testimony and "review" of the USGS water level data. These arguments bear directly on Bartlett's credibility as a scientist and his knowledge and review of documents/data prior to composing his expert report. While Bartlett's justifications are late-developing, his review of the data was an exercise of professional judgment and cannot be decided as a matter of law. Whether this evidence was properly excluded under the guise of "professional judgment" is in total dispute. It must be weighed and decided by the trier of fact.

There is an additional controversy giving rise to the existence of a disputed issue of scientific material fact. Mr. Bartlett and Dr. Schmidt, the Court's independent expert, dispute the source for well water for MWC-2 and, critically, the presence and extent of Corcoran clay layer beneath MWC-2. Bartlett says there is a non-continuous clay layer at approximately 90 feet bgs and that the primary water source for MWC-2 is the contaminated shallow aquifer above 90 feet. Bartlett also opines that water enters the well through the open annulus above the well casing and through holes in the casing. Dr. Schmidt opines that a relatively impermeable Corcoran clay layer at 88 to 94 feet bgs acts as a barrier and MWC-2 draws its production water from a deeper, unconfined and uncontaminated aquifer. The scientific opinions on the breadth/expanse of the clay layer are conflicting and susceptible of at least two reasonable interpretations. These two contrasting views from scientists represent a factual scientific dispute, an issue that a jury must decide.

Under Daubert, a partially-calibrated model may not be scientifically sound. In the groundwater context given that field observations play such a critical role in ensuring reliability, calibration is scientifically important. See, e.g., Natural Resources Defense Council, Inc. v. Muszynski, 268 F.3d 91, 102 (2nd Cir.2001) ("If the model is not closely calibrated, [i.e., if an agricultural use of land, for example, contributes significantly more than the expected amount of phosphorus to the adjoining water body], regulation of phosphorus concentrations in the reservoirs becomes an uncertain matter."). A half-calibrated model is, by definition, inadequately calibrated and excluded under Daubert. See Mitchell, 165 F.3d 778, 782 ("Under Daubert, any step that renders the expert's analysis unreliable [. . .] renders the testimony inadmissible.").

Plaintiffs contend that the BAC Defendants' Daubert motion fails because Defendants challenge the "matters clearly going to the weight of the[ ] testimony and not the admissibility of the[] testimony under Rule 702 and Daubert." (Doc. 792 at 1:17-2:2.) Under Daubert, however, any scientifically required step that renders the expert's analysis unreliable renders the testimony inadmissible. This is true whether the step completely changes a reliable methodology or merely misapplies that methodology. Bartlett's failure to calibrate his entire model to field data is premised on the alleged unreliability of the MWC-2 well test data and the monitoring well data. This is a highly risk-laden choice. If Plaintiffs cannot prove the unreliability of the well water quality (metals) test data, their groundwater expert and modeler has left them without an alternative explanation and justification for the existing model or an alternative model. Daubert does not prohibit proof of this theory, but will still exclude the Bartlett model. This must be determined at trial.

Two federal cases analyzing the admissibility of expert groundwater modeling under Rule 702, City of Wichita, Kansas v. Trustees of APCO Oil Corp. Liquidating Trust, 306 F.Supp.2d 1040 (D.Kan.2003) and Sterling v. Velsicol Chemical Corp., 855 F.2d 1188, are instructive.

In City of Wichita, 306 F.Supp.2d 1040, the City brought a private CERCLA action against potentially responsible parties, seeking contribution for prior response costs and declaration of responsibility for future response costs. Id. at 1107. Prior to trial, defendants moved in limine to bar the testimony of Michael J. Smith, the City's expert witness regarding groundwater modeling. Id. The motions were denied without prejudice to reassertion in post-trial submissions. Following an eight-week bench trial on the CERCLA issues, defendants renewed and supplemented their motions to exclude Smith's trial testimony. Id.

The Court "decline[d] to credit the majority of Smith's testimony because it `fail[ed]' to meet the requirements of the Federal Rules of Evidence and applicable case law." Id. The expert used three proprietary codes: DYNFLOW for the flow component, DYNTRACK for the contaminant transport, and CHAIN, a government model, to analyze contaminant transport when there is degradation of the contaminants. The Court analyzed the utility and application of computer modeling to groundwater modeling:

Id. at 1108.

The Court described the calibration process as "a reasonable fit to the field data," Id. at 1109, and found that Smith took considerable leeway in his "professional judgment," which resulted in the Court giving "Smith's testimony and his modeling [. . .] little weight":

Id.

In this case Bartlett has rejected and explained the field data based on the exercise of "professional judgment."

In Sterling, 855 F.2d 1188, the Sixth Circuit affirmed the denial of a motion to exclude a groundwater model on the basis that "district court carefully considered the plaintiffs' model, including its components and the data it utilized." Id. at 1199. Sterling considered a class action against a chemical manufacturer for personal injuries and property damage allegedly caused by contaminant exposure from its chemical waste burial site. Judgment was entered in favor of plaintiffs. On appeal, the corporation attacked the plaintiffs' expert model as unreliable because it failed to utilize all of the relevant domestic well data. The Sixth Circuit disagreed, finding that the failure to incorporate selected well samplings conducted after 1978 did not invalidate the model and conclusions based on the model:

Id.

These two cases demonstrate the level of scrutiny that must be applied to the Bartlett model. First, like the expert in City of Wichita, Bartlett exercised his professional judgment to depart from the field data, which revealed that there was no hexavalent contamination at that MWC-2 well, at that time. Bartlett's use of his professional judgment resulted in an allocation of hexavalent chromium contamination at MWC-2 that manifestly deviated from the field data. Scientific reliable methodology, as described by Mr. Stephens and the authoritative treatises, suggests further examination after some number of tests revealed no hexavalent chromium contamination at MWC-2 or the nearby monitoring wells. Although it is undisputed that modeling is not an exact science, the sheer volume of non-detects followed by a lack of calibration or adjustment raises serious concerns.

Sterling is distinguishable from this case. There, the expert excluded truly "irregular" testing data, however, the expert calibrated his model to the EPA's testing in 1978, as well as the remaining scientific studies and monitoring data. The exclusion of the post-1978 data was supported by scientific principles. Neither of those steps were taken in this case.

Plaintiffs next distinguish Ramsey, 111 F.Supp.2d 1030, and the other groundwater modeling cases cited by the BAC Defendants on grounds that those cases did not involve challenges to the reliability of the underlying data. Plaintiffs argue that the factual dispute on the data's reliability creates a triable issue of fact over the issue of groundwater contamination in the Beachwood neighborhood. See Ralston v. Smith & Nephew Richards, Inc., 275 F.3d 965, 970 n. 4 (10th Cir.2001) (the proponent of expert testimony bears the burden of showing that its proffered expert's testimony is admissible). Plaintiffs proffer several arguments to support of their position.

Plaintiffs first argue that the sampling data was properly excluded from its expert's model because there was insufficient documentation and Defendants "lack credibility" with respect to "information related to the MWC-2 site." In particular, Plaintiffs contend that Defendant Meadowbrook's sampling data is untrustworthy because it was conducted pursuant to the "honor system":

(Doc. 792 at 4:4-4:17.)

Plaintiffs further theorize that BAC Defendants, specifically Defendant Merck, engaged in a "conspiracy to destroy and/or manipulate the BAC site sampling records":

(Id. at 6:7-7:9.)

The allegations of improper documentation and conduct are based on hindsight and not supported by any specific facts.63 Plaintiffs fault the RWQCB for not instituting special procedures for consultants paid by the allegedly offending-entities. They criticize RWQCB's uniform sampling standards, as far back as 1964, including the documentation requirements at the monitoring site, lack of state personnel at the site, and means of authentication. Plaintiffs, however, overlook the fact that identical sampling evidence has been relied on in a number of federal court cases, including City of Fresno v. United States, 709 F.Supp.2d 888 (E.D.Cal.2010), Santa Clara Valley Water Dist. v. Olin Corp., 655 F.Supp.2d 1066 (N.D.Cal.2009) and Waste Management of Alameda County, Inc. v. East Bay Regional Park Dist., 135 F.Supp.2d 1071 (N.D.Cal.2001). Plaintiffs have cited no legal authority holding that sampling authorized and then certified by the RWQCB is unreliable, otherwise lacking credibility, or that it is subject to manipulation by independent testing laboratories or state employees who certify testing results. The MWC-2 intervals in this case are criticized for not meeting the tri-annual testing frequency called for by State regulations.

Here, the samples collected at MWC-2 and monitoring wells at or near the BAC site were tested and/or verified by the RWQCB. At the time the samples were taken, they complied with the RWQCB's scientific and chain-of-custody requirements. There is no evidence, other than argument, to show otherwise. An attack on all samples ever collected and/or verified by the RWQCB is without support in the record. In addition, Plaintiffs' allegations of a Merck-led conspiracy at the BAC site are speculative and unsupported by any factual citations. To create a genuine issue of disputed fact on the Phase 1 issues, the disputed conduct must be based on facts not argument.

Plaintiffs levy a number of non-scientific attacks on the entities/agencies involved in collecting and verifying the data in an attempt to prove a Merck-led conspiracy. Specifically, Plaintiffs characterize the RWQCB for being "over-worked and understaffed" and Meadowbrook Water Company as a "small and unsophisticated water company." At the same time, Plaintiffs note Merck's size, corporate status, and alleged experience with environmental disputes. These arguments are all disputed.

Second, Plaintiffs refer to the supplemental declaration of their groundwater expert, Mr. Bartlett, to argue that there is a triable issue on the global groundwater issue because there is an alleged dispute over the reliability of sampling data from MWC-2. In his supplemental declaration, Bartlett opines:

(Doc. 777 at ¶ 5.)

Bartlett is not licensed in California and there is no record evidence that he has an expertise in California water sample collection and water quality assurance formalities required by the State of California. It is unknown if he has ever personally taken or observed sampling at groundwater, domestic, or monitoring wells in California or any other state. Second, he takes inconsistent positions concerning the validity of data provided to the RWQCB and there is a dispute whether he had personal knowledge of the MWC-2 data prior to building his model. As discussed above, none of MWC-2's alleged foundational deficiencies are delineated in his Rule 26 expert report.

Following the October 15, 2010 oral argument, Meadowbrook Water Company was directed to produce the relevant foundational documents, i.e., the company's laboratory records for the relevant time periods, authenticated by a declaration from its custodian of records. (Doc. 863.) Meadowbrook Water Company complied with the request on October 20th by filing Constance Farris' declaration and attaching the lab results. In her declaration, Ms. Farris states that she maintains the business records of Meadowbrook Water Company and the laboratory results were kept in the ordinary course of business. These laboratory results are summarized as follows:

----------------------------------------------------------------------------------------
        Collection                                                      Reading
Well    Test Date        Sampler                 Lab                    (Chr.VI)
----------------------------------------------------------------------------------------
MWC-2   Aug. 1974        Signed by R. Brooks     Merced County          ND < 10
----------------------------------------------------------------------------------------
MWC-2   March 19, 1980   Signed by M. Banuelos   Twining Labs, Inc.     ND < Cal ML
----------------------------------------------------------------------------------------
MWC-2   June 9, 1987     P. Espinosa             Cal. Water Labs        ND < 10
----------------------------------------------------------------------------------------
MWC-2   Jan. 3, 1990     D. Adams                Cal. Water Labs        ND < 10
----------------------------------------------------------------------------------------
MWC-2   March 9, 1993    T. Stevens              APPL., Inc.            ND < 10
----------------------------------------------------------------------------------------
MWC-2   Dec. 21, 1995    T. Stevens              APPL., Inc.            ND < 10
----------------------------------------------------------------------------------------
MWC-2   Feb. 17, 1995    T. Stephenson           BSK Laboratories,      ND < 10
                                                 Inc.
----------------------------------------------------------------------------------------
MWC-2   Sep. 13, 2001    MWC -                   BSK Laboratories,      2.0 ppb
                                                 Inc.
----------------------------------------------------------------------------------------
MWC-2   Feb. 12, 2002    MWC                     BSK Laboratories,      Total Chrom
                                                 Inc.                   (12 ppb)
                                                                        Chrom IV
                                                                        (1 ppb)
----------------------------------------------------------------------------------------
MWC-2   March 11, 2005   MWC                     BSK Laboratories,      Total Chrom (ND)
                                                 Inc.
----------------------------------------------------------------------------------------
MWC-2   March 2, 2007    BC Laboratories         BC Laboratories,       Total Chrom
                                                                        (ND, 3.0)
                                                                        Chrom IV (1.8
                                                                        and 1.6 ppb)
----------------------------------------------------------------------------------------
MWC-2   12 samples       Arcadis                 Arcadis                Total Chrom (ND)
        (May 15, 2007                                                   Chrom IV
        to Sep. 18,                                                     (2.1 ppb)
        2008)
----------------------------------------------------------------------------------------

The declaration of Ms. Farris and the attached sampling records rebut the quality control criticisms and other alleged foundational deficiencies, however, they indicate that Meadowbrook did not produce well samples a tri-annual basis, the regulatory standard.

2. Conclusion on Groundwater Pathway

The degree of variance between Bartlett's model and the well data requires a factual foundation to decide the truth of Bartlett's grounds for minimizing most of the observed test data. This credibility determination will bear on the ultimate admissibility of the model. The Court reserves the right to exclude the model after hearing the evidentiary foundation for the model at trial.

The BAC Defendants' Daubert motion is DENIED subject to the express reservation described in detail in this Memorandum Decision. If proceedings during trial ultimately reveal that Bartlett's model is not supported by a proper scientific foundation, it will be subject to a motion to strike at trial under Daubert.

Because a scientific factual dispute remains as to the admissibility of the Bartlett model, which was proffered to demonstrate chromium contamination via the groundwater pathway (specifically, in MWC-2 from 1969 onward), that portion of the motion for partial summary judgment is also DENIED without prejudice.

E. Pathway # 3 — Private Wells

The BAC Defendants argue that summary judgment is proper because Plaintiffs have provided no evidence of contaminant exposure via the private well pathway.64 In particular, Defendants assert that "neither plaintiffs nor their experts have produced a shred of sampling data to show that there was any elevated concentration of any contaminant in any private well used for drinking water at any time."

Defendants include a water sampling history in their motion, (Doc. 677-1), but a more specific "private well" fact recitation is required:65 Defendants assert that two offsite well surveys were conducted by consultant IT Corp., the first in 1992. This survey was conducted under the supervision of the RWQCB in the Beachwood neighborhood immediately after the discovery of off-site contamination at the M & A Market, which is located across Santa Fe Drive from the BAC Site. In carrying out the survey, BAC and IT searched public records and walked door-to-door through the northeast portion of the Beachwood neighborhood looking for private domestic wells. Most of the wells were shallow and dry. The survey found only one well in use at 2942 Elm Avenue. The well water was tested and no hexavalent chromium or arsenic were found. The results were provided to the county and homeowners, and those homes that were not already connected to the Meadowbrook system were connected at BAC expense.

In 1999, IT Corp. conducted a second well survey under the supervision of the RWQCB. They surveyed a well to the north of the BAC Site because the groundwater flow had shifted to the north (north was then the downgradient direction of flow). The second survey also included a door-to-door survey to confirm the presence of abandoned or active wells. Two active domestic wells were identified and tested. According to Defendants, background concentration levels of hexavalent chromium were detected in one of the wells (3.9 ug/l). The second well contained no detectable levels of hexavalent chromium. Arsenic was not found in either well.

According to Defendants, these facts demonstrate that concentrations of hexavalent chromium and arsenic in domestic wells were at or below background concentrations and well below the state MCL for chromium (50 ug/l).

Plaintiffs rely on the expert testimony of Richard Laton, a purported expert in the field of hydrology and hyrdogeology. Laton opines that domestic wells utilized by plaintiffs have been impacted by chemicals of concern from the former BAC facility resulting in significant pathways of exposure to those plaintiffs; and given the detections in the monitoring well network, "it is a scientific certainty that hexavalent chromium and chromium reached residential wells in the Beachwood neighborhood." (Doc. 778 at ¶ 8.)

Dr. Laton next opines that the monitoring well data sufficiently establishes that contamination reached several domestic wells in the Beachwood neighborhood:

(Id. at ¶ 10.)

Although Dr. Laton's criticisms concerning the "failure to investigate" add nothing to the Phase 1 inquiry, his comments concerning the Bartlett model are significant. According to Plaintiffs, the monitoring well data, together with the Bartlett model, establish that MWC-2 and the private domestic wells drew water from the same contaminated plume:

(Rough RT, Dec. 29, 2010, 89:18-90:7.)

There is some merit to Plaintiffs' position. Although it is Plaintiffs' burden to establish private well contamination, that proof requires admission — and acceptance — of the Bartlett model. The Bartlett model is relevant to a degree, because it suggests that MWC-2, the monitoring wells, and the domestic wells drew water from the same contaminated plume causing injury to the well users and the community. At the same time, however, Plaintiffs have a proof problem. Despite their arguments concerning the lack of sampling and alleged "plume" sharing, neither Dr. Laton nor Dr. Bartlett identify a specific private well allegedly containing hexavalent chromium or arsenic during the relevant time-period. Nor do they identify a specific concentration of contamination allegedly present in any private well.

There is a proper approach to this evidence and how to present it to the jury, particularly in view of its dependence on the Bartlett model. It has been previously determined that Bartlett's testimony is conditionally admissible, subject to a motion to strike. The same conditions applies to the surface water pathway. If Bartlett's model and testimony are ultimately inadmissible at trial, the modeling evidence showing domestic well contamination will also be excluded.66

The nature and extent of the "shared plume" remains in dispute. To date, however, Plaintiffs have not provided evidence except argument and hyperbole addressing Merck's alleged corporate misconduct and failure to provide environmental notice. Plaintiffs failed to prove the BAC Defendants' lack of diligence and corporate misfeasance during the Daubert hearings. It was marginally relevant, at best.

The BAC Defendants' motion for partial summary judgment on the private well pathway is DENIED subject to the express reservations described in this Memorandum Decision. Plaintiffs must make a particularized showing of private domestic well contamination based on admissible evidence.67

VI. CONCLUSION.

For the reasons stated:

IT IS SO ORDERED.