FILED
                                                  United States Court of Appeals
                     UNITED STATES COURT OF APPEALS       Tenth Circuit

                            FOR THE TENTH CIRCUIT                      January 29, 2013

                                                                     Elisabeth A. Shumaker
                                                                         Clerk of Court
THOMAS HOWELL,

             Plaintiff-Appellant,

v.                                                          No. 12-1127
                                               (D.C. No. 1:09-CV-02299-MSK-CBS)
CENTRIC GROUP, LLC;                                          (D. Colo.)
SCENTOILS.COM, INC.,

             Defendants-Appellees.


                             ORDER AND JUDGMENT*


Before ANDERSON and BALDOCK, Circuit Judges, and BRORBY, Senior Circuit
Judge.


      In this product-liability case, Thomas Howell appeals pro se from a final

judgment entered in favor of Centric Group, LLC, and Scentoils.com, Inc., on the

issue of causation. We have jurisdiction under 28 U.S.C. § 1291, and we affirm for

substantially the same reasons identified by the district court.



*
      After examining the briefs and appellate record, this panel has determined
unanimously that oral argument would not materially assist the determination of this
appeal. See Fed. R. App. P. 34(a)(2); 10th Cir. R. 34.1(G). The case is therefore
ordered submitted without oral argument. This order and judgment is not binding
precedent, except under the doctrines of law of the case, res judicata, and collateral
estoppel. It may be cited, however, for its persuasive value consistent with
Fed. R. App. P. 32.1 and 10th Cir. R. 32.1.
                                    BACKGROUND

      Howell is a Colorado state prisoner who claims he was injured in 2006 by

“anise oil” that he applied under his nose and which he had purchased from the

prison’s canteen service. R. at 533. Anise oil “is derived from organic plant

materials.” 

material safety data sheet (MSDS) states that the oil “may

be irritating to skin and eyes,” “vapor may be irritating to throat and lungs,”

“breathing high concentrations of vapor may cause anesthetic effects,” and “repeated

contact may cause allergic dermatitis.” 

warning on the bottle

purchased by Howell provides: “NOT FOR INTERNAL USE.” 

states that in order to cover up offensive odors in his cell, he rubbed

the anise oil on the skin under his nose “many” times over “a few days” and then

“excessively” on one particular night. 

next morning, he woke up

with “pus and blood” under his nose. 

prison nurse commented that the

injury “appears as 1st degree burn.” 

two weeks later,

physician’s assistant Theodore Laurence examined Howell and described the injury

as “Rash and other nonspecific skin eruption—Probably chemical burn.” 

time, Howell developed “a scar, loss of smell, and discoloration of a

portion of [his] mustauche [sic] hair.” 

months after the initial

injury, physician’s assistant Tejinder Singh examined Howell and reported: “0.5cm

by 1cm scar just below the right nares. Patient informed the loss of smell due to




                                          -2-
injury of specialized nerve tissue at the top [of his] nose[,] and his sense of smell

may never come back.” 

sued the company that distributed the oil to the prison, Centric, and the

company that sold it to Centric, Scentoils.com. The district court construed his

complaint as invoking diversity jurisdiction and advancing four claims for relief:

(1) negligence; (2) failure to warn; (3) negligence per se, and (4) strict product

liability.

       As to Centric’s liability, both Centric and Howell moved for summary

judgment. The district court concluded that all of Howell’s claims failed because he

failed to show that the anise oil was the specific cause of his injuries. The court

noted that while the MSDS might alone be sufficient to show that anise oil could

cause injury, there was no evidence to show “that the oil was the actual cause of his

injury.” R. at 698. Indeed, Howell admitted in his deposition that prior to using the

anise oil, he “was using other oils,” 

that he had been dabbing oil on

his upper lip “since the ‘90s,” 

the court concluded that expert

testimony was necessary to show that the anise oil, rather than something else,

caused his injury. And the court rejected Howell’s offer to use his medical providers

as experts, as they had never opined that the anise oil caused his injuries.

       Howell sought reconsideration, and both he and Scentoils.com moved for

summary judgment on the latter’s liability. The district court denied reconsideration,

reiterating that Howell lacked any evidence showing that the anise oil was the


                                          -3-
specific cause of his injuries. Regarding summary judgment, the court found the

causation issue determinative, and it entered judgment for Scentoils.com.

      Howell appeals.

                                      DISCUSSION1

      Where, as here, the district court has ruled on cross-motions for summary

judgment, we review its orders de novo, “constru[ing] all factual inferences in favor

of the party against whom summary judgment was obtained.” NISH v. Rumsfeld,

, 1266 (10th Cir. 2003). Summary judgment is appropriate “if the

movant shows that there is no genuine dispute as to any material fact and the movant

is entitled to judgment as a matter of law.” Fed. R. Civ. P. 56(a). “We review a

district court’s denial of a Fed. R. Civ. P. 59(e) motion for reconsideration under an

abuse of discretion standard,” reversing only if the court “made a clear error of

judgment or exceeded the bounds of permissible choice in the circumstances.” Ysais

v. Richardson, 

, 1180 (10th Cir. 2010) (quotation omitted).

      The crux of Howell’s summary-judgment challenge is that “his medical

documents are enough to show that . . . his treating physicians can testify at trial as to

the likelihood or probability that defendants’ conduct or product caused his injuries.”

Aplt. Opening Br. at 11. We disagree.



1
      “Although we liberally construe pro se filings, we do not assume the role of
advocate.” Yang v. Archuleta, 

, 927 n.1 (10th Cir. 2008) (quotation
omitted).


                                          -4-
      Preliminarily, we note that causation is a necessary component of all Colorado

product-liability claims. See Colo. Rev. Stat. § 13-21-401(2). And when such claims

target allegedly toxic substances or pharmaceuticals, courts throughout the country

routinely require plaintiffs to show both general and specific causation. See, e.g.,

Johnson v. Arkema, Inc., 

, 457, 468-69 (5th Cir. 2012) (holding that

exposure to vaporized “organometallic compound” not shown to be general cause of

injury); Norris v. Baxter Healthcare Corp., 

, 881 (10th Cir. 2005)

(stating that “in silicone breast implant litigation, plaintiffs must show both general

and specific causation”); see generally Restatement (Third) of Torts: Liability for

Physical & Emotional Harm § 28 (2010) (“The concepts of general causation and

specific causation are widely accepted among courts confronting causation issues

with toxic agents.”). “General causation is whether a substance is capable of causing

a particular injury or condition in the general population and specific causation is

whether a substance caused a particular individual’s injury.” 

.

      Even if we assume, as the district court did, that anise oil is capable of causing

injuries similar to those Howell complained of, he has provided no evidence that the

anise oil was the actual cause of those injuries. Indeed, Howell’s own testimony

shows that anise oil was not the only oil he has been applying under his nose.

“[W]here an injury has multiple potential etiologies, expert testimony is necessary to

establish causation.” Wills v. Amerada Hess Corp., 

, 46 (2d Cir. 2004)

(Jones Act case); see also Tamraz v. Lincoln Elec. Co., 

, 674 (6th Cir.


                                          -5-
2010) (rejecting expert’s opinion that defendants’ welding products caused plaintiff’s

Parkinson’s disease because, among other things, expert provided only speculation to

rule out other possible causes). Further, Howell’s “treating physicians” appear to be

the prison’s nurse and two physician’s assistants—none of whom have opined that

anise oil caused his injuries.2

       Because Howell failed to provide any evidence of specific causation, summary

judgment was appropriate. Cf. Pluck v. BP Oil Pipeline Co., 

, 676-77

(6th Cir. 2011) (stating that toxic tort cases require expert scientific assessments

concerning general and specific causation); Junk v. Terminix Int’l Co., 

,

450 (8th Cir. 2010) (holding that expert testimony was required to show insecticide

compound was the general and specific cause of a newborn’s injuries). And given

that he failed to remedy that deficiency in his Rule 59(e) motion, the district court

acted within its discretion by denying reconsideration.




2
       Although Howell contends on appeal that “Dr. Beecroft” assisted the prison
nurse and physician’s assistants, Aplt. Opening Br. at 23, it does not appear that
Dr. Beecroft has examined Howell regarding the injuries alleged in this litigation or
provided any opinion as to the specific cause of those injuries.


                                          -6-
                                    CONCLUSION

      The judgment of the district court is affirmed for substantially the same

reasons identified in that court’s September 27, 2011, and March 28, 2012, orders.

                                              Entered for the Court



                                              Wade Brorby
                                              Senior Circuit Judge




                                        -7-