UNITED STATES CO URT OF APPEALS FOR THE TENTH CIRCUIT

________________ _________________ CHARLES BRYER, Plai ntiff - Appellant,

v. CONOCOPHILLIPS, CO.; PHILLIPS 66, CO.,
De fendants - Appellees. No. 17-6114 (D.C. No. 5:15-CV-01218-HE) (W.D. Okla.)

________________ _________________ ORDER AND JUDGMENT *

________________ _________________ Before BACHARACH , MURPHY , and McHUGH , Circuit Judges.

________________ _________________ This appeal involves an issue of timeliness. The plaintiff, Mr. Charles Bryer, live d near an oil refinery that emitted a chemical known as benzene. Years later, he was diagnosed with a fo rm of leukemia known as Acute Myeloid Leukemia. Mr. Bryer sued the owner of th e refinery, Conoc oPhillips, for negligence, negligence per se, and strict liability. But he waited to sue until roughly nine years after his diagnosis. Be cause a two-year limitations

* This order and judgme nt does not constitute bi nding precedent except under the doctrines of law of the case, res judicata, and collateral estoppel. But the order and judgment may be ci ted for its persuasive value under Fed. R. App. P. 32.1(a) and Tenth Cir. R. 32.1(A). FILED United States Court of Appeals Tenth Circuit 

### February 21, 2018
Elisabeth A. Shumaker Clerk of Court2 period exists for these claims, the district court dismissed the suit based on timeliness. We affirm.
I. Background Mr. Bryer grew up in Ponca City , Oklahoma, near ConocoPhillips’s refinery. For part of that time, Mr. Bryer also wo rked near the refinery. While living and working near the refinery, Mr. Bryer experienced symptoms—such as trouble breathing and a burning sensation in his eyes— from emissions generated by the refinery. These symptoms led Mr. Bryer to move away from th e refinery in 1975. Mr. Bryer was not alone, and many Ponca City citizens expressed concerns about the refinery. These concerns led a group of Ponca City residents to bring a class-action suit against ConocoPhillip s, claiming that the refinery had emitted carcinogenic chemicals, including benzene. The suit focused on property damage, but th e plaintiffs also alleged that the refinery’s emissions had ca used or increased the ri sk of various diseases, including cancer. ConocoPhillips settled and paid members of the class in 1990. Mr. Bryer was one of the class members receivi ng a payment from the settlement. He knew at th e time that the payment was to compensate for exposure to pollutants emitted by the refinery. Roughly sixteen years later (2006), a physician diagnosed Mr. Bryer with Acute Myeloid Leukemia, telling him that benzene exposure from his3 residences and workplaces had “likely contributed to” his leukemia. Appellant’s App’x at 132. Mr. Bryer di d not follow up with his doctors about the cause or source of his cancer. In 2015, Mr. Bryer met Ms. Sa mantha Hall, who had sued ConocoPhillips. Ms. Hall told Mr. Bryer that a connection existed between the refinery’s emissions and Acute Myeloid Leukemia. Later that year, Mr. Bryer sued ConocoPhillips, attributin g his leukemia to the refinery’s emissions of benzene.
II. Procedural History In district court, ConocoPhillips moved fo r summary judgment, arguing that the claim ha d accrued in 2006, which is when Mr. Bryer had been diagnosed with leukemia. Becaus e a two-year period of limitations existed, ConocoPhillips argued that the suit was time- barred. Mr. Bryer argued that

 his claim had not accr ued until his meeting with Ms. Hall in 2015 and

 the doctrine of quasi-estoppel prevented ConocoPhillips from raising a timeliness defense. The district court granted summary judgment to ConocoPhillips, concluding that

 the claim was untimely because Mr. Bryer shou ld have known the underlying facts mo re than two years be fore he sued and

 quasi-estoppel did not apply because ConocoPhillips had not advanced inconsistent positions.4 Mr. Bryer appeals the gran t of summary judgment.
III. Standard of Review We engage in de novo review, cons idering the eviden ce in the light most favorable to Mr. Bryer. Grynberg v. Total S.A. , 538 F.3d 1336, 1346 (10th Cir. 2008). We must uphold the grant of su mmary judgment if the evidence points only one way and is not susceptib le to a reasonable inference that the suit is timely. Elm Ridge Expl. Co. v. Engle , 721 F.3d 1199, 1216 (10th Cir. 2013).
IV. Is the suit barred by the statute of limitations? As both parties acknowle dge, we apply Oklahom a law on substantive aspects of our timeliness inquiry, in cluding Oklahoma’s rules on tolling. Id. at 1210. 1 On procedural aspects of this inquiry, however, we apply federal law. Budinich v. Becton Dickinson & Co. , 807 F.2d 155 , 158 (10th Cir. 1986) (per curiam). The parties agree on th e applicability of Oklaho ma’s two-year period of limitations for all of Mr. Bryer’s claims. Okla. St at. tit. 12, § 95(A)(3). The suit began in 2015. Therefore, the suit would ordinarily be considered timely only if the cause of action ha d accrued since 2013. Mr. Bryer argues

1 We strive to interp ret Oklahoma law in th e same manner that the Oklahoma Supreme Court would. Schrock v. Wyeth, Inc. , 727 F.3d 1273, 1280 (10th Cir. 2013).5 that the cause of action accrued in 2015; ConocoPhillips argues that the cause of action accrued in 2006. A. The Discovery Rule The discovery rule tolls the statute of limitati ons until the plaintiff knows, or in the exercise of reasonable dilige nce should know, the facts underlying the cause of action. Watkins v. Cent. Stat e Griffin Mem’l Hosp. , 377 P.3d 124, 132 (Okla. 2016). Under this stan dard, a plaintiff “is chargeable with know ledge of facts which he ough t to have di scovered in the exercise of r easonable diligence.” Daugherty v. Farm ers Coop. Ass’n , 689 P.2d 947, 951 (Okla. 1984). When the discovery rule applies, the statute of lim itations is tolled until the plaintiff knows or should know of the injury and th e cause of the injury. Woods v. Prestwick House, Inc. , 247 P.3d 1183, 1189-90 (Okla. 2011). Knowledge of the in jury and its cause would often be sufficient. But here recognition of a ca use of action would al so require knowing the source of the benzene. We may assu me, for the sake of argument, that uncertainty about the sour ce of the emissions coul d toll the statute of limitations. Under this assumption, th e discovery rule would have tolled the statute of limitations until Mr. Brye r knew or shoul d have known of

 his injury (that he had leukemia),

 the cause of his injury (that the leukemia had been caused by benzene exposure), and6  the source of the be nzene (that ConocoPhil lips’s refinery had emitted the benzene caus ing the leukemia). Both parties assume that the discov ery rule applies. For the sake of argument, we too may draw the same assumption.
B. Application of the Discovery Rule As noted above, summary judgment to ConocoPhillips was appropriate if the undis puted evidence showed that Mr. Bryer should reasonably have known be fore 2013: (1) hi s injury, (2) th e cause of the injury, and (3) the source of the benzene emissions. 1. Injury It is undisputed that Mr. Bryer knew of his inju ry in 2006—nine years before he sued C onocoPhillips—when his docto rs diagnosed him with leukemia. 2. Cause It is also undisputed that Mr. Br yer knew the cause of his leukemia (benzene exposure) in 2006, when his doctor told him that exposure to benzene had “likely contributed to” his leukemia. Appellant’s App’x at 132; see Schrock v. Wyeth, Inc. , 727 F.3d 1273, 1280 (10th Cir. 2013) (stating that the plainti ff was aware of the cause of her symptoms when her7 doctor told her th at a certain chemical was “q uite possib[ly]” responsible for her symptoms). 2
3. Source Mr. Bryer argues that he did not know the sour ce of the benzene until 2015, when he spoke with Ms. Hall. This argument cr eates two issues:
1. When did Mr. Bryer know that the refinery emitted benzene?
2. When did he kno w that the refinery’s benzene emissions were the likely cause of his leukemia?

a. Knowledge of Benzene Emi ssions from the Refinery Mr. Bryer should have known by 2006 that the re finery emitted benzene. Mr. Bryer argues in his reply brief that he could no t have known that the Ponca City refi nery’s emissions had included benzene. Mr. Bryer forfeited this argument by failing to raise it in his opening brief. Bronson
v. Swensen , 500 F.3d 1099, 1104 (10th Cir. 2007). 3 Mr. Bryer’s argument would fail even if we were to overlook the forfeiture. Mr. Bryer knew not on ly that the refi nery had emitted a

2 Mr. Bryer contends that the limita tions period does not begin to run until an expert expresses an opin ion on causation. For the sake of argument, we assume that Mr. Bryer is right. But th is assumption does not help him because an expert did expr ess an opinion on causation in 2006 when his physician attributed th e leukemia to be nzene exposure.

3 When an appellant omits an argume nt in the opening brief, we have sometimes referred to th e omission as a forfeiture and sometimes as a waiver. Compare Bronson , 500 F.3d at 1104 (forfeiture), with Anderson v. U.S. Dep’t of Labor , 422 F.3d 1155, 1174 (10t h Cir. 2005) (waiver).8 significant volume of chemicals but also that these emissions had included benzene. For example, Mr . Bryer was aware that

 other Ponca City residents had expressed concerns about the refinery’s emissions and thei r impact on health and the environment and

 these concerns had led to a cl ass-action complaint alleging harmful levels of benzene em issions from the refinery. Other sources of information were also available to Mr. Bryer before 2013. For example, multiple artic les had noted the emission of benzene from the refinery. In addition, Mr. Bryer was a member of the class-action suit against ConocoPhillips, wh ich alleged that the Po nca City refinery had emitted harmful levels of be nzene that increased the class members’ risk of health problems. An d the eventual settlement agreemen t acknowledged that all class members had been advised by their attorneys and a medical advisor that the ConocoPh illips refinery had caused , or may cause, cancer or an increased risk of cancer. 4 Though Mr. Bryer might not have read the settlement agreement, he knew when he received hi s settlement check that ConocoPhillips was se ttling because the refinery had polluted the air and groundwater. Of course, these facts do not esta blish that the refinery’s benzene emissions were sufficiently concentrated to be harm ful; indeed, that is the

4 Mr. Bryer asserts that he should not ha ve been expected to remember the terms in a settlement agreement that he signed sixteen years earlier. But a reasonably diligen t plaintiff coul d have obtained a settlement agreement that he or she had signed.9 ultimate question on the merits. And Mr. Bryer’s knowledge of allegations of high levels of benzene emission s did not provide him with certain knowledge of the refinery’s high emission s of benzene. But Mr. Bryer did not need “conclusive evidence.” Alexander v. Oklahoma , 382 F.3d 1206, 1216 (10th Cir. 2004). Instead, he needed enough information to put him on notice that he had a cause of action against ConocoPhillips. Based on the available information, Mr. Bryer knew or should ha ve known that the refinery’s emissions ha d included benzene.
b. Knowledge of the Refinery as the Likely Source For a cause of action, Mr. Brye r also needed to know that the refinery had been the likely source of the benzene. Maughan v. SW Servicing, Inc. , 758 F.2d 1381, 1387 (10th Cir. 1985). Mr. Bryer should have been able to obtain this know ledge before 2013. Mr. Bryer was diagno sed with leukemia in 2006 and told that the likely cause was benzene exposure from his residences and workplaces. In addition to this statement, Mr. Bryer had his own recollection of symptoms from the refinery’s emissions, knowledg e that the refinery had emitted benzene, awareness of the public controversy su rrounding the refinery’s emissions, and his own participation in a class-action suit alleging that ConocoPhillips’s benzene em issions had increased the risk of cancer. With such information, Mr. Br yer could reasonably have known before 2013 that10 his leukemia had likely been cause d by benzene emi ssions coming from ConocoPhillips’ s refinery. Mr. Bryer relies primarily on Maughan v. SW Servicing, Inc. , 758 F.2d 1381 (10th Cir. 1985). In Maughan , the court relaxed Utah’s discovery rule for cases involving suspected carcinogens because

 such cases frequently invo lve “a mass of complex, controversial and rapidly chan ging scientific data” and

 plaintiffs “may face enormous difficulties in de termining when and where [they were] exposed to potential carcinogens.” 758 F.2d at 1385-86. The co urt stated that when the su spected cause is a carcinogen, “the statute mu st be tolled until the plaintiff knows or should know of facts supporting the likelihood th at one particul ar suspected carcinogen was the ca use of his cancer, and has identified the likely source of his exposure to that carcinogen .” Id. at 1387 (emphasis added). Mr. Bryer does not dispute the first part of that test, for he acknowledges that benzene caused the leukemi a. But he invokes the se cond part of the test, arguing that he could not have identified the refinery as the likely source of his exposure to benzene. 5
In Maughan , the court relied largely on scientific uncer tainty about the cause of the cancer. There the plaintiffs attr ibuted the cancer to

5 Mr. Bryer argues in his reply brief that the cancer might have originated from exposure to benzene at his other jobs. But Mr. Bryer forfeited this argument by waiting to raise it for th e first time in his reply brief. See p. 7 & note 3, above.11 radiation from the defendan t’s uranium mill. But th e doctors had told the plaintiffs that the cause of the can cer was “unknown,” and the link between low levels of radiation and cancer had not been scientific ally established. Id. at 1386. The Maughan court added that even if the link between radiation and cancer had been established, the plain tiffs lacked information tying their cancers to the defendant’s radiation: [T]he mere fact that there we re public statements concerning the possible link betw een radiation and leukemia is not enough to establish, as a matter of law, that the plain tiffs should have known that emissions from the uranium processi ng plant in Monticello were the likely cau se of the leukemia of their children and spouse. None of the articles cited by the defendants directly and unamb iguously links th e Monticello mill tailings with leuk emia. Nor can it be said, as a matter of law, that the average layman would understand, after reading that fall-out from atomic bomb s causes cancer, that the local uranium mill may have caus ed decedents’ leukemia. Id. at 1388. The court point ed to government studies, whic h had reassured the plaintiffs of (1) the absence of any connection between the mill and the cases of leukemia and (2) the existence of normal radiation levels at the mill. Id. at 1389. Mr. Bryer analogizes these reassurances to ConocoPhillips’s pub lic statements about the ab sence of danger from the refinery’s emissions. Based on Maughan , Mr. Bryer argues th at even though the carcinogenic potential of benzene wa s well known, he lacked enough12 information tying the refinery to his leukemia. Maughan ’s language is broad, but there are two problems with Mr . Bryer’s argument:
1. Unlike the plaintiffs in Maughan , Mr. Bryer had ample information identifying the refinery as a likely source of the benzene that caus ed his cancer.
2. Mr. Bryer has not provided evidence of other plausible sources of exposure to suffic iently high concentr ations of benzene. First, there is far less scient ific uncertainty here than in Maughan . In Maughan , the cause of the cancer was not known, so it was inherently difficult for the plaintiffs to attribute their cancer to the defe ndant’s mill. But Mr. Bryer was able to tie his injury to ConocoPhillips’s refinery. A physician told him not only that benz ene had likely caus ed his cancer but also that the exposure ha d likely come from his residences and workplaces. This explanation pointed to the refinery because Mr. Bryer had lived and worked near the refinery when he experienced the symptoms from chemical emissions. And Mr. Bryer participat ed in a class-action suit against ConocoPhillips, which attr ibuted cancer to ben zene emissions from the Ponca City refinery. T ogether, the facts known an d accessible to Mr. Bryer diminished the scientific uncertainty that the plaintiffs in Maughan had faced. See Grynberg v. Total S.A. , 538 F.3d 1336, 1349-50 (10th Cir. 2008) (distinguishing Maughan because the plaintiff in Grynberg had not faced “similar scientific uncertaint y or lack of expertise”).13 Second, Mr. Bryer has not supplied a plausibl e alternative to the refinery as the source of the benzene. For example, he does not give any details on whether his othe r jobs exposed him to be nzene and, if so, how much. As a result, the re finery is the only plausible source based on the information in the summary-judgment record. See Plaza Speedw ay Inc. v. United States , 311 F.3d 1262, 1270-71 (10th Cir. 2002) (holding that the plaintiffs had sufficient information wh en they discovered contaminants in their well with “reason to suspect the source migh t have been the neighboring property” becaus e they knew that various ch emicals had been used on the neighbo ring property); accord Corcoran v. N.Y. Power Auth. , 202 F.3d 530, 543-44 (2d Cir. 1999) (holding that a claim accrued when the plaintiff knew that he “may have been expose d to radiation” at his workplace, that he had leukemia, and th at a link existed between leukemia and radiation exposure). In addition, Mr. Bryer does not identify any evidence of information learned since 2013 about the likelihood of the refinery as the source of his leukemia. Mr. Bryer states that in 2015, he overheard Ms. Samantha Hall note a connection between the refinery’s emissions and Acute Myeloid Leukemia. Mr. Bryer then contacte d Ms. Hall to obtain additional information, leading him to file the complaint in this case. But Ms. Hall simply provided a contact with her law firm , alerting Mr. Bryer to the fact that others had also accused Conoco Phillips of causing their cancers.14 In essence, everyt hing Mr. Bryer knows a bout his case now was accessible to him before 2013; there is nothing that Mr. Bryer alleges now that he could not have a lleged before. Therefore, he could have brought his suit before 2013 and the su it is barred by the st atute of limitations. See Samuel Roberts Noble Found. v. Vick , 840 P.2d 619, 625 (Okla. 1992) (“The operative date [for the discovery-rule inquiry] is that da te on which plaintiff could have brought suit.”).
* * * In summary, Mr. Bryer knew or should have known before 2013 that

 he had leukemia,

 his leukemia had likely been caused by exposure to benzene,

 his exposure to benzene likely came from his residences and workplaces,

 he had lived and worked near the Ponca City refinery for much of his life,

 he had experienced symptoms while living and working near the refinery,

 the refinery had em itted benzene, and

 ConocoPhillips had se ttled a lawsuit—in wh ich Mr. Bryer was a class member and received a settlement payment—alleging that the refinery had emitted to xic levels of benzene that caused or increased th e risk of cancer. Given these facts, Mr. Br yer was on notice before 2013 of the facts giving rise to his claim. Ther efore, the 2015 suit is barred by Oklahoma’s twoyear statute of limitations.15 V. Is ConocoPhillips’s statute-of-lim itations defense barred by quasi-estoppel? Mr. Bryer also argues that Conoco Phillips’s denial of culpability prevents assertion of the statute of limitations. We disagree. Mr. Bryer invokes the doctrine of quasi-estoppel, which “appeals to the conscience of the court to preven t injustice by precl uding a party from asserting a right inconsistent with a position previously taken by him.” Willard v. Ward , 875 P.2d 441, 443 (Okla. Ci v. App. 1994). Mr. Bryer insists that ConocoPhillips is trying to assert a right (the statute-oflimitations defense) that is inconsiste nt with its previous position (its longstanding denial that the refinery caused ca ncer). According to Mr. Bryer, it is inconsistent for ConocoPhi llips to deny that its refinery causes leukemia and then say that Mr. Bryer should have known years earlier that the refinery had ca used his leukemia. The Oklahoma Suprem e Court recognizes th ree circumstances in which estoppel can be used to avoid a statute-of-limitations defense:
1. The defendant has made “‘so me assurance of settlement negotiations reasonably calculated to lull the plaintiff into a sense of security and dela y action beyond the statutory period.’”
2. The defendant has made “‘an express and re peated admission of liability in conjunction with promises of payment, settlement or performance.’”
3. The defendant has engaged in “‘any false, fraudulent or misleading conduct or some affirm ative act of concealment to16 exclude suspicion an d preclude inquiry, wh ich induces one to refrain from timely bringing an action.’” Watkins v. Cent. Stat e Griffin Mem’l Hosp. , 377 P.3d 124, 131 & n.18 (Okla. 2016) (quoting Jarvis v. City of Stillwater , 732 P.2d 470, 472-73 (Okla. 1987)). Mr. Bryer cannot fit his facts into any of the three categories. To avoid this difficulty, Mr. Bryer urge s another form of estoppel, quasiestoppel. But Oklahoma’s “[e]xceptions to statut es of limitations are strictly construed and are not enla rged on consideration of apparent hardship or inconvenience.” Calvert v. Swinford , 382 P.3d 1028, 1033 (Okla. 2016). And the Okla homa courts have never extended qua si-estoppel to a statute-of-limitations case. Therefore, we d ecline to recognize a new exception in Oklahoma to the statute of limitations. See Hogan v. Okla. Dep’t of Corr. , 172 F.3d 878, at *2 (10th Cir. 1999) (unpublished) (“Absent affirmative indication that the State of Ok lahoma recognizes equitable tolling in such a case, we decline to impute such a doct rine to the state.”). VI. Conclusion We conclude that

 Mr. Bryer had sufficient information to bring his claim against ConocoPhillips more than two ye ars before the filing of the complaint and

 the doctrine of quasi-es toppel does not apply.17 These conclusions render the complain t untimely, and we affirm the grant of summary judgment to ConocoPhillips. Entered for the Court

Robert E. Bacharach Circuit Judge