IN THE SUPREME COURT OF IOWA

No. 21–0723

Submitted December 14, 2022—Filed June 23, 2023

JACQUELINE SUE UHLER,

Appellant,

vs.

THE GRAHAM GROUP, INC.,

Appellee.

On review from the Iowa Court of Appeals.

Appeal from the Iowa District Court for Polk County, Samantha Gronewald, Judge.

A plaintiff alleging a permanent lung injury from exposure to chemical vapors in a building seeks further review of the court of appeals decision affirming 

the district court’s grant of summary judgment in favor of the building’s owner. 

DECISION OF COURT OF APPEALS AND DISTRICT COURT JUDGMENT AFFIRMED.

McDermott, J., delivered the opinion of the court, in which Christensen, 

C.J., and Waterman and Mansfield, JJ., joined. McDonald, J., filed a dissenting 

opinion, in which Oxley, J. joined. May, J., took no part in the consideration or 

decision of this case.

Jason D. Walke (argued) of Walke Law, LLC, West Des Moines, and Troy 

A. Skinner of Skinner & Paschke, PLLC, West Des Moines, for appellant.
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James S. Blackburn (argued) of Finley Law Firm, P.C., Des Moines, for 

appellee.
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McDERMOTT, Justice.

Jacqueline Uhler alleges that she suffered a permanent lung injury from 

toxic vapors that spread throughout the multistory building where she worked

after a maintenance worker poured a chemical drain cleaner down a sink. The 

district court dismissed her claim, determining that she failed to offer evidence 

to establish the element of causation. In this appeal, we must decide whether 

Uhler presented evidence to create a dispute of material fact about whether her 

exposure to the chemical’s vapors caused her permanent lung injury.

I. Facts and Procedural Background.

A maintenance worker at a medical office building, responding to a call 

about a clogged restroom sink on a lower level, used a chemical drain cleaner 

called Draynamite to clear the clog. Although he didn’t measure out the chemical 

as he was using it—instead pouring directly from the bottle into the sink—he 

estimates that he used “about a cup.” The building’s maintenance crew had used 

Draynamite to clear clogged sinks in the building in the past with no problems. 

When he returned to the restroom about ten minutes later, the clog had cleared.

The maintenance manager’s phone soon rang with complaints from two 

different people in offices on the building’s third and fourth levels about a rottenegg smell. The maintenance worker and his manager quickly began opening 

stairwell doors throughout the building, setting up fans, and redirecting airflow 

using the building’s computerized ventilation system. It reportedly took ten to

thirty minutes to air out the building (although some occupants reported that 

they could still detect an odor the next day). 
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A number of the building’s workers felt sick and went home for the rest of 

the afternoon, and a pediatric clinic on the building’s third level closed early. The 

next day, eleven workers filed incident reports about the odor. The complaints 

ranged from nausea, headaches, and dizziness to chest tightness, burning sensation, severe cough, and shortness of breath.

Uhler was among those who experienced adverse symptoms that afternoon. As soon as she experienced those symptoms, she asked permission to 

leave and went home. She worked in a cubicle in a records area on the building’s 

fourth level—four floors above the restroom sink treated with Draynamite. Like 

the others, she described a chemical, rotten-egg smell. In her incident report the 

next day, she reported a headache, nausea, and difficulty breathing. A coworker 

seated about five cubicles away said that the odor was stronger around Uhler’s 

cubicle. 

Two days after the incident, Uhler sought medical treatment for breathing 

trouble. Uhler was 78 years old at the time of the incident and had been previously diagnosed with asthma. A pulmonologist to whom Uhler had been sent, 

Dr. Gregory Hicklin, diagnosed Uhler with a permanent lung injury and prescribed medication, including medicated inhalers. Uhler reports that her asthma 

and general pulmonary function worsened after the incident. Although her condition has stabilized to some extent, Uhler has continued to report shortness of 

breath and difficulty doing many activities she once enjoyed.

Uhler sued the building’s owner and manager, Graham Group, Inc., for 

negligence. Characterizing her cause of action as a premises liability claim, Uhler 
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alleges that Graham Group failed to maintain the premises and ventilate the 

building adequately, warn tenants of the danger in a timely and safe fashion, 

and minimize and contain the chemical exposure. She asserts that her inhalation of the fumes in the building aggravated her preexisting asthmatic condition 

and caused permanently reduced pulmonary function.

After discovery in the case, Graham Group moved for summary judgment, 

arguing that Uhler had failed to present sufficient evidence that the chemical 

fumes caused the permanent lung injury that she alleges. The district court 

granted the motion and dismissed Uhler’s claim. Uhler appealed. We transferred 

the case to the court of appeals, which affirmed the district court judgment over

a dissent. Uhler sought further review, which we granted.

II. Uhler’s Evidence of Causation.

Uhler characterizes her negligence cause of action as a premises liability 

claim, not a toxic tort. She thus doesn’t discuss the two types of causation—

general and specific—that we require plaintiffs to show to prove factual causation 

in toxic tort cases. See Ranes v. Adams Lab’ys, Inc., 778 N.W.2d 677, 687–88

(Iowa 2010). Toxic torts generally “involve plaintiffs who have been exposed to 

allegedly toxic substances, such as chemicals, asbestos fibers, or a pharmaceutical product, and allege that this exposure has caused their cancer, birth defect, 

or other injury.” David E. Bernstein, Getting to Causation in Toxic Tort Cases, 74 

Brook. L. Rev. 51, 51 n.1 (2008) [hereinafter Bernstein]. Uhler’s cause of action, 
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as pleaded, alleges that she was exposed to toxic fumes from the use of a chemical drain cleaner and that the exposure caused permanent lung damage. That’s 

a toxic tort claim, so we will apply our bifurcated causation analysis.

General causation is a showing that the substance in question was capable of causing the injury alleged. Ranes, 778 N.W.2d at 688; Bernstein, 74 Brook. 

L. Rev. at 52–53. Specific causation is a showing that the exposure to the substance in fact caused the plaintiff’s injury. Ranes, 778 N.W.2d at 688; Bernstein, 

74 Brook. L. Rev. at 52–53. We’ve described general causation as a process of 

“ruling in” possible causes for the injury, and specific causation as a process of 

“ruling out” those possible causes through a process of elimination. Ranes, 778 

N.W.2d at 695. 

Uhler argues that the manufacturer’s own safety data sheet establishes 

that inhaling Draynamite vapors is capable of causing serious damage to the 

lungs and, thus, a jury question on causation prevents summary judgment. The 

safety data sheet for Draynamite includes this statement:

Risk of serious damage to the lungs (by inhalation). Causes burns 

to the respiratory tract, nose, mouth, and throat with discomfort, 

nasal discharge, sneezing, coughing, rapid heartbeat, and chest 

pain. Inhalation of mist or vapors may cause chemical pneumonia 

which can cause damage and may be fatal.

But disclosures required on a chemical safety data sheet are a step removed from 

establishing causation. A manufacturer’s duty to provide basic information 

about hazards on safety data sheets is imposed by federal regulation. See 29 

C.F.R. § 1910.1200(b)(1), (g) (2012). “Regulatory standards are set for purposes 

far different than determining the preponderance of evidence in a toxic tort case.”
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Bernard D. Goldstein & Mary Sue Henifin, Fed. Judicial Center, Reference Guide 

on Toxicology, in Reference Manual on Scientific Evidence 633, 665 (3d ed. 2011)

[hereinafter Reference Manual on Scientific Evidence]. A safety data sheet alone 

isn’t sufficient to establish causation in a toxic tort case because the sheets 

aren’t evidence of what a toxic level of exposure might be, whether a particular 

person was exposed to a toxic dosage, or whether the person’s exposure actually 

caused her injuries. See Gass v. Marriott Hotel Servs., Inc., 501 F. Supp. 2d 1011, 

1025 (W.D. Mich. 2007), rev’d and remanded on other grounds, 558 F.3d 419 

(6th Cir. 2009).

The safety data sheet proves that Draynamite is a toxin capable of causing 

injury by inhaling its vapors, but it doesn’t prove that the vapors actually drifted 

through the building to reach Uhler in a concentration sufficient to cause the 

permanent lung injury that she alleges. To show that her exposure to Draynamite vapors caused her injury, Uhler needed to present evidence of the level of 

her exposure to the toxin and that that level could cause the injury she alleges.

The main issue surrounds “whether there has been exposure to a sufficient dose 

to be a likely cause of this effect.” Reference Manual on Scientific Evidence at 638.

Concentration levels of toxins are influenced by a number of variables, including

dilution. A simple example illustrates the point: A drop of undiluted acid on your 

skin might cause a horrible burn, while the same drop in a bathtub might reduce 

the concentration such that you experience no effect. Id. at 641 n.25.

Uhler has presented evidence that the fumes traveled through four floors 

of the building in some concentration, and that the fumes were associated with 
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brief symptoms in at least eleven people in the building. But this evidence of a 

temporal connection between exposure to fumes and temporary symptoms, without more, doesn’t permit the leap that the exposure involved toxins of a quantity 

capable of causing the permanently reduced pulmonary function. See Cavallo v. 

Star Enter., 892 F. Supp. 756, 769–75 (E.D. Va. 1995) (granting summary judgment where expert testimony was based primarily on a temporal connection between exposure to jet fuel and the plaintiff’s onset of chronic respiratory illness)

aff’d in part and rev’d and remanded in part on other grounds, 100 F.3d 1150 

(4th Cir. 1996).

What’s more, the temporary symptoms that some in the building experienced aren’t what Uhler alleges in this case; her claim seeks damages for a permanent injury. Yet she presents no evidence that the exposure to fumes caused 

anyone else to suffer anything other than discomfort that subsided after leaving 

the building. This evidence of causation—that the concentration of toxin emanating in her workspace from the release of Draynamite was capable of causing

her permanent lung injury—requires expert testimony. Uhler didn’t offer it.

Uhler designated three physicians (two of them her treating physicians) as 

experts: Dr. Gregory Hicklin, Dr. Daniel Dodge, and Dr. Jacqueline Stoken. But 

Dr. Hicklin, a pulmonologist, is the only expert she designated to offer an opinion 

about causation. Dr. Hicklin initially treated Uhler after the incident. Regrettably, Dr. Hicklin died in the time between the incident and Uhler’s filing of her 

lawsuit; he never prepared an expert report for this case. Uhler provided some of 

Dr. Hicklin’s treatment records with her summary judgment materials. But as 
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the district court found, Dr. Hicklin’s records are silent about the concentration 

and toxicity of Draynamite fumes that could have reached Uhler, and whether 

that concentration was capable of causing the permanent injury she alleges.

Uhler’s other experts, both osteopathic medicine physicians, fare no better 

on this issue. Dr. Stoken specializes in rehabilitation medicine. Her expert affidavit says that she has treated patients with pulmonary injuries from inhaling 

fumes from toxic chemicals. But she offers no opinion about the dosage of toxin 

that could have reached Uhler and whether that dosage was capable of causing 

Uhler’s permanent injury. Dr. Dodge specializes in pulmonology, which focuses 

on ailments of the respiratory system. He took over Uhler’s pulmonary treatment 

for Dr. Hicklin. Like Dr. Stoken, Dr. Dodge offers no opinion about the dosage of 

toxin that could have circulated four floors up to Uhler’s workspace or whether 

that dosage was capable of causing Uhler’s permanent injury.

To prove general causation in this case, Uhler needed a toxicology expert. 

Toxicology, as a scientific endeavor, “attempts to determine at what doses foreign 

agents produce their effects.” Reference Manual on Scientific Evidence at 637. 

Toxicology’s oldest maxim is that “the dose makes the poison.” Bernard D. Goldstein, Toxic Torts: The Devil Is in the Dose, 16 J.L. & Pol’y 551, 551, 554–55

(2008). Unlike a toxicologist, “most physicians have little training in chemical 

toxicology and lack an understanding of exposure assessment and dose–response relationships.” Reference Manual on Scientific Evidence at 676. Uhler offered no expert opinion from a toxicologist. Dr. Stoken’s expert affidavit, which 
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Uhler seems to rely on most for the causation issue, essentially offers that exposure to Draynamite, followed by Uhler’s permanent injury diagnosis, establishes 

causation. But this conclusion assumes that the exposure was capable of causing the injury. This step in the analytical process—evidence of general causation—is skipped. Evidence that a plaintiff’s symptoms are “consistent with” exposure to a particular chemical doesn’t satisfy the plaintiff’s burden of proof as 

to causation. See Turpin v. Merrell Dow Pharms., Inc., 959 F.2d 1349, 1359–61

(6th Cir. 1992) (holding that proof that a drug is “ ‘capable of causing,’ ‘could 

cause’ or that its effects are ‘consistent with causing’ birth defects” was evidence 

of a possibility rather than a probability and thus insufficient to support a finding of causation); see also Bland v. Verizon Wireless, (VAW) L.L.C., 538 F.3d 893, 

897, 899 (8th Cir. 2008) (affirming summary judgment where a treating physician didn’t know what amount of exposure to freon caused, or would have an 

appreciable risk of causing, asthma).

At some point, a dose of sulfuric acid—the toxic agent that Uhler points to 

in Draynamite as triggering her disease—becomes so low that it can’t produce a 

particular effect. See Reference Manual on Scientific Evidence at 635–36, 669. 

The complexity in understanding the dose–response relationship between Draynamite fumes and a person’s lungs places the causation question in this case 

well beyond a layperson’s knowledge. A toxicologist measures exposure, for instance, “by mathematical modeling, in which one uses a variety of physical factors to estimate the transport of the pollutant from the source to the receptor.” 
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Id. at 666. That type of evidence of exposure is absent in this summary judgment 

record.

Uhler cites Bloomquist v. Wapello County for the proposition that juries can 

use “traditional cause and effect” testimony from physicians to resolve causation 

questions and that epidemiological evidence is not “an absolute requirement in 

establishing causation” in a toxic tort case. 500 N.W.2d 1, 3, 5 (Iowa 1993). These 

propositions, while true, have limited application in this case. As the court of 

appeals explained, the evidence of the plaintiffs’ exposure to the chemical pesticide in Bloomquist involved evidence about the repeatedly monthly exposures 

(from broadcast spraying inside work offices on desks, papers, carpets, and 

seemingly all points between). See id. at 1. The evidence also included data from 

on-site testing conducted to determine the amount of chemical residue still on 

the carpets in the offices where the plaintiffs worked. Id. at 3. What’s more, and 

as the court of appeals correctly observed, nothing in Bloomquist permits a reading that expert epidemiological testimony is never required to establish exposure 

levels in toxic tort cases, only that it isn’t “an absolute requirement.” Id. at 5 

(emphasis added).

We don’t require mathematical precision in equating levels of exposure 

with levels of harm to prove causation. See Wright v. Willamette Indus., Inc., 91 

F.3d 1105, 1107 (8th Cir. 1996). We recognize that “[t]oxicologists also have indirect means of approaching exposure through symptoms. For many agents, 

there is a known threshold for smell and a reasonable range of levels that might 

cause symptoms.” Reference Manual on Scientific Evidence at 657 n.66. But what 
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is that threshold for Draynamite? Dr. Stoken’s affidavit states that inhalation of 

sulfuric acid fumes “even in small amounts” could cause pulmonary injury, yet 

we’re left to guess what that means, both as to the amount and the severity of 

injury. Is a cup or two of Draynamite capable of producing enough vapor to circulate through a large office building and reach four floors above while retaining 

enough toxic potency to cause permanent pulmonary damage? None of Uhler’s 

experts answer this question. Without some offer of evidence on this point, a jury 

is left to speculate, and speculation won’t do. “Guesses, even if educated, are 

insufficient to prove the level of exposure in a toxic tort case.” Mitchell v. Gencorp 

Inc., 165 F.3d 778, 781 (10th Cir. 1999); see also Wright, 91 F.3d at 1106 (reversing the jury’s verdict in a toxic tort case for failing to offer evidence of “the 

plaintiff’s actual level of exposure to the defendant’s toxic substance”).

Whether a plaintiff has proved causation is generally a jury question. 

Thompson v. Kaczinski, 774 N.W.2d 829, 836 (Iowa 2009). But when a tort claim 

requires an expert witness to prove causation, and no expert presents this evidence, the claim is properly dismissed on summary judgment because “[s]peculation is not sufficient to generate a genuine issue of fact.” Hlubek v. Pelecky, 701 

N.W.2d 93, 95–96 (Iowa 2005). Expert testimony is often critical in toxic tort 

cases to prove causation. Ranes, 778 N.W.2d at 688. Indeed, in Ranes v. Adams 

Laboratories, Inc., we determined that expert medical and toxicological testimony 

was “unquestionably required to assist the jury” on general and specific causation. Id. A plaintiff’s “[f]ailure to reliably ‘rule in’ the defendant’s [toxin] as a cause 
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of the injuries in a particular case is commonly fatal to plaintiffs seeking to survive summary judgment in toxic tort cases.” Id. at 690.

And so it is in this case. “When the analytical gap between the evidence 

presented and the inferences to be drawn is too wide, a jury should not be asked 

to speculate on the issue of causation.” Gass, 501 F. Supp. 2d at 1026. Because 

Uhler presented insufficient evidence about whether the dose of toxin to which 

she was exposed was capable of causing the permanent injury alleged, she has 

failed to establish a necessary element of her claim. We thus affirm the judgment 

of the district court granting summary judgment in favor of Graham Group and 

affirm the decision of the court of appeals.

DECISION OF COURT OF APPEALS AND DISTRICT COURT JUDGMENT 

AFFIRMED.

Christensen, C.J., and Waterman and Mansfield, JJ., join this opinion. 

McDonald, J., files a dissenting opinion, in which Oxley, J., joins. May, J., takes 

no part.
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#21–0723, Uhler v. The Graham Group, Inc.

McDONALD, Justice (dissenting).

“It is the duty of the jury to decide issues of fact.” Grismore v. Consol. Prods.

Co., 5 N.W.2d 646, 656 (Iowa 1942). Causation is an issue of fact and “ordinarily 

a jury question.” Garr v. City of Ottumwa, 846 N.W.2d 865, 870 (Iowa 2014). It 

is only in the “very exceptional cases where the facts are so clear and undisputed, 

and the relation of cause and effect so apparent to every candid mind” that a 

court should grant summary judgment on causation. Lindquist v. Des Moines 

Union Ry., 30 N.W.2d 120, 123 (Iowa 1947) (quoting Fitter v. Iowa Tel. Co., 121 

N.W. 48, 50 (Iowa 1909)). This is not one of the very exceptional cases where 

summary judgment on the fact question of causation is appropriate. On the contrary, there is more evidence establishing causation in this summary judgment 

record than disproving it. I thus respectfully dissent.

In affirming the grant of summary judgment and denying Uhler her right 

to present her case to a jury, my colleagues misapply Ranes v. Adams Laboratories, Inc., 778 N.W.2d 677 (Iowa 2010). In Ranes, we adopted and applied a “bifurcated toxic-tort-causation analysis” to claims arising out of the use of phenylpropanolamine, an ingredient used for three decades in many cough and cold 

products. Id. at 682, 687. Under this bifurcated analysis, we separated causation 

into two parts: general causation and specific causation. Id. at 687–88. “General 

causation is a showing that the drug or chemical is capable of causing the type 

of harm from which the plaintiff suffers. Specific causation is evidence that the 

drug or chemical in fact caused the harm from which the plaintiff suffers.” Id. at 
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688 (citation omitted). We explained that general causation and specific causation were merely “device[s] to organize a court’s analysis” and not “additional 

elements of the tort.” Id. (quoting Restatement (Third) of Torts: Liab. for Physical 

& Emotional Harm § 28 cmt. c, at 405 (Am. L. Inst. 2010) [hereinafter Restatement (Third)]).

The bifurcated causation framework adopted and applied in Ranes is appropriate and useful in certain categories of toxic tort cases. “Cases involving 

toxic substances often pose difficult problems of proof of factual causation.” Restatement (Third) § 28 cmt. c, at 402. In certain types of toxic tort cases, like 

Ranes, there are a host of unknown issues presented regarding exposure, latency, etiology, environmental factors, preexisting conditions, and alternative potential causes of disease, to name a few. The Restatement (Third) explains:

By contrast, the causes of some diseases, especially those with significant latency periods, are generally much less well understood. 

Even known causes for certain diseases may explain only a fraction 

of the incidence of such diseases, with the remainder due to unknown causes. Causal agents are often identified in group (epidemiologic) studies that reveal an increase in disease incidence among a 

group exposed to the agent as compared to a group not exposed. 

Biological mechanisms for disease development—i.e., a series of 

causally linked physiological changes from exposure to disease development—are frequently complicated and difficult to observe. 

Id.

The bifurcated framework is not appropriate or useful in all toxic tort 

cases, however. In some cases the bifurcated causation analysis is inappropriate 

and not useful because “the plaintiff can prove the causal role of the defendant’s 

tortious conduct by observation, based upon reasonable inferences drawn from 

everyday experience and a close temporal and spatial connection between that 
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conduct and the harm. Often no other potential causes of injury exist.” Id. In 

other words, as the Restatement (Third) explains, “the evidence bearing on specific causation may be sufficient to pretermit the need to assess general causation.” Id. at 407.

To make the abstract more concrete: general causation and specific causation are at issue in every case. In an automobile collision case, there is a general causation question—whether the cars collided with sufficient force to be capable of causing the type of harm the plaintiff suffered—and there is a specific 

causation question—whether the collision in fact caused the harm the plaintiff 

suffered. In automobile collision cases, however, courts do not apply the bifurcated general causation and specific causation framework. Courts do not require 

plaintiffs to obtain a physicist to opine on the force of the automobile collision 

and opine on whether the force was sufficient to cause the harm at issue. The 

temporal relationship between the collision and the injury is sufficient to establish a nonspeculative inference of causation, both general and specific.

The same analysis applies in this case. While the majority tries to frame 

this case as a complicated toxic tort case that requires extraordinary proof of 

causation from an epidemiologist—like the toxic exposures at issue in the oftmentioned Bendectin, Agent Orange, and asbestos class-action cases—it is not. 

This is a single-exposure case where injury occurred almost immediately after 

exposure. It is more of a traumatic injury case akin to an automobile collision

case. This type of case is sometimes called an “isolated exposure” or “sporadic 

accident” case. See Kuhn v. Sandoz Pharms. Corp., 14 P.3d 1170, 1184–85 (Kan.
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2000). In this type of case, the bifurcated causation analysis is unnecessary to 

organize the court’s analysis, and the testimony of a physician is generally sufficient to establish a triable issue of fact on causation:

[D]ecisions such as those in the Bendectin and Agent Orange cases, 

which have demanded confirming epidemiological proof in order to 

make out a prima facie case, can be explained and better understood, in comparison to decisions such as Ferebee, which did not 

require such proof, by examining whether the exposures were, in 

fact, mass exposures or, in contrast, were limited or isolated ones. 

The courts should explicitly recognize that isolated exposure 

cases are in reality more typical tort cases that can more comfortably be placed into the sporadic accident model of tort law. 

. . . In isolated exposure cases, where only a single plaintiff or a few 

persons have allegedly suffered harm from a toxic exposure, it is fair 

and reasonable to allow the traditional sporadic accident model to 

exert greater influence. A medical doctor is permitted to render an 

opinion as to whether, to a reasonable degree of medical certainty, 

exposure to Agent X caused the plaintiff’s physical disability. This 

standard of causation will be referred to as the “testifying treating 

physician” standard, and Ferebee is the paradigm case articulating 

this standard. In rendering an opinion on causation under this 

standard, the expert is not typically required to demonstrate the existence of supporting epidemiological data (or even much other toxicological proof) in order to justify admission of that opinion and to 

reach a jury on that issue. 

Gerald W. Boston, A Mass-Exposure Model of Toxic Causation: The Content of 

Scientific Proof and the Regulatory Experience, 18 Colum. J. Env’t L. 181, 188–

89 (1993) (emphasis added) (footnote omitted).

With that understanding, when the summary judgment record is viewed 

in the light most favorable to Uhler, the district court erred in granting the defendant’s motion for summary judgment because there is a disputed issue of fact 

regarding causation. First, consider the chemical at issue—Draynamite. The material safety data sheet for Draynamite cautioned that “Acute Inhalation Toxicity 

– Vapers” posed a “Category 2” risk. It also cautioned: “odor pungent acidic,” 
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“fatal if inhaled,” “obtain special instructions before use,” “wear respiratory protection,” “use in a well-ventilated area,” “IF INHALED: Remove person to fresh 

air and keep at rest in a position comfortable for breathing,” “local ventilation is 

suggested to control exposure from operations that can generate significant levels of vapour, mist or fumes,” “risk of serious damage to lungs (by inhalation),” 

“causes burns to the respiratory tract,” and “inhalation of mist or vapors may 

cause chemical pneumonia.”

Next consider the close temporal and spatial relationship between the defendant’s use of Draynamite in the building and the immediate and simultaneous onset of injury to Uhler and others. Sometime after noon, the defendant’s 

maintenance workers received a complaint of a clogged sink on the basement 

level of the building where Uhler worked. Brad Grismore responded to the complaint. Grismore poured Draynamite down the drain to unclog the sink. Within 

minutes of Grismore pouring Draynamite down the sink, Toby George, another 

maintenance employee, received a call from a tenant who reported a strange odor 

on the second floor. It smelled like rotten eggs. George contacted Grismore, who 

said he was in the basement tending to the clogged sink. George joined Grismore

in the basement and could smell something. George “hurried back up to his office 

one floor above, got on his computer and adjusted the settings on the building’s 

air circulation system to vent out all circulating air in the system to the outside 

of the building and to have all fresh outside air come into the system.”

Within minutes, people who worked in the building began to suffer various 

injuries. Eleven people filed incident reports about what happened that day. Four 
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of the people worked on the third story, where Uhler worked. Seven of the people 

worked on the second story. Not all of the incident reports are legible, but the 

summary judgment record shows the following:

• One person “started smelling rotten eggs.” She experienced “flu 

like symptoms.” She described her type of injury as “chest burning-indigestion-belching.”

• Another person “started smelling odor.” She said her “lungs” were 

the “body part affected by the injury.” She said it was “hard to 

breathe” and she was “coughing.” As for the type of injury, she 

said, “breathing/severe cough last night and cough & chest tightness today.”

• Another person started smelling “fumes.” She reported injuries 

as “lungs, sinus, headache.” She described her type of injury as 

shortness of breath, headache, and congestion.

• Another person complained of headache, dizziness, and nausea.

• Another said, “Started smelling sulfur/sewer smell. Continued to 

get stronger. Started getting headache within 15-20 min. Nausea 

and dizziness.” She described her type of injury as “headache, 

nausea, dizziness, shortness of breath.”

• Another person described a “horrible smell in the clinic and we 

had to close.” She stated she had a “headache” and was

“nau[seous], dizzy, today I feel dizzy. I can’t remember things.”

• Another reported fumes caused headache and stomachache.

• Another stated, “Fumes were circulating through the clinic air 

system.” She stated this caused nausea and chest tightness. She 

described her body part affected as “stomach, head, lungs” and 

her type of injury as “headache, nausea, short of breath.”

• Another person described “fumes” and the injury as “headaches, 

nausea, breathing.” 

Uhler’s experience was similar to the ten other people who reported an injury

on the day in question. Uhler started having trouble breathing. She asked for,
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and was granted, permission to leave as soon as she started experiencing symptoms. She saw Dr. Daphney Myrtil two days later for her symptoms. The doctor’s 

report states Uhler’s chief complaint was “inhalation exposure to hydrogen sulfide” from “fumes in the building.” The report confirms “inhalation exposure 

symptoms” and a history of asthma. The report further states that since the 

incident, “she has been having symptoms of eye irritation, she has had a slight 

headache, and she does feel like her nose is irritated as well.” Dr. Myrtil performed a chest X-ray that showed “hyperinflation” in the lungs. Then, after an 

“acute worsening of her asthma,” Uhler treated with pulmonologist Gregory Hicklin. Dr. Hicklin noted Uhler’s lung condition had been stable until her exposure 

at work. 

The close temporal and spatial relationship between Grismore’s use of the 

Draynamite, the immediate onset of injury to Uhler, and the corroborating work 

incident reports from at least ten other people in the building are more than 

sufficient to “rule in” Draynamite as a cause of injury. See Cavallo v. Star Enter., 

892 F. Supp. 756, 774 (E.D. Va. 1995) (“[I]f a known chemical is accidentally 

introduced into a company’s ventilation system, and all of the workers exposed 

immediately develop the same adverse reaction, then the episode itself may be 

sufficiently indicative of causation.”), aff’d in part, rev’d in part, 100 F.3d 1150 

(4th Cir. 1996).

Next, consider the fact that there is no other plausible explanation for what 

happened sufficient to rule out Draynamite as a cause of injury. Grismore testified there was not “one specific plausible explanation for the complaints . . . other 
21

than [his] use of the Draynamite product in the basement of the building that 

day.” George testified that he could not “offer any explanation for the complaints 

of the people who say they got sick . . . besides the use of chemicals in the basement.” Jeff Hatfield, Graham Group’s senior vice president of medical properties,

also testified. Hatfield was George and Grismore’s boss. Hatfield stated he did 

not “have a single plausible specific explanation for what happened that day that 

does not involve the use of Draynamite in the basement.”

Not only has Graham Group failed to identify any alternative explanation 

of harm—Graham Group has affirmatively admitted that the cause of harm to 

the tenants’ employees was the Draynamite used in the building. A clinic administrator in the building at issue testified that she was told by Graham Group that 

“the cause of all this was they had poured something down the drain.” Another 

supervisor in the building was told by Graham Group “that there was a cup of 

drain cleaner poured into a basement sink drain, and it resulted in fumes.” Hatfield testified about the steps Graham Group took to investigate what happened 

on the day in question. Based on Graham Group’s investigation, he testified that

the use of Draynamite “was part of what caused problems. We’re not sure what 

it interacted with.”

Next, consider the medical opinions provided by Uhler’s experts in resistance to the motion for summary judgment. Dr. Jacqueline Stoken stated she 

was qualified to opine on lung injuries due to her education, training, and experience working in pulmonary care. In preparing her opinion, she relied on her 

education, training, and experience; she examined Uhler; she reviewed Uhler’s 
22

medical records; she reviewed Graham Group’s answers to interrogatories; she 

reviewed the material safety data sheets for Draynamite; and she reviewed the 

employee incident reports. She opined that Uhler has a preexisting medical condition that made her more susceptible to injury from exposure to Draynamite. 

She opined that Uhler’s injuries that day (and since) were caused by her exposure to fumes generated by the use of Draynamite in the building. She also 

opined that Uhler suffered a “long term permanent worsening of her asthma” as 

a result of her exposure to Draynamite on the day in question; the “chemical 

fume injury” caused “a material aggravation of [Uhler’s] underlying asthma and 

permanent lung damage.” Pulmonologist Dr. Daniel Dodge opined that Uhler’s 

exposure to Draynamite in the workplace caused a “significant and permanent 

worsening of her pre-existing asthma.” 

The majority’s response to all of this is that there is no evidence the 

amount of Draynamite poured down the drain was generally capable of causing 

Uhler’s harm, so she loses. This is vaporous. “We do not require a mathematically precise table equating levels of exposure with levels of harm” to prove causation. Wright v. Willamette Indus., Inc., 91 F.3d 1105, 1107 (8th Cir. 1996). And 

we do not demand evidence of the exact dose where, as here, the evidence may 

very well be impossible to produce. Spaur v. Owens–Corning Fiberglas Corp., 510 

N.W.2d 854, 861 (Iowa 1994) (holding “the jury could infer that [the defendant] 

was a contributing cause of [the plaintiff’s] disease” because “it is not necessary 

and indeed may be impossible to establish exactly how much” exposure plaintiff 

experienced). 
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More important, the general causation evidence the majority now demands 

is not needed because the close temporal and spatial relationship between the 

defendant’s use of Draynamite and the onset of simultaneous injury to at least 

eleven people within the building is sufficient to establish both general and specific causation. See Bonner v. ISP Techs., Inc., 259 F.3d 924, 931 (8th Cir. 2001) 

(affirming jury award in toxic tort case where “the immediacy of [plaintiff’s] acute 

symptoms to her exposure” was sufficient to establish causation); Kuhn, 14 P.3d 

at 1184–85 (“A medical doctor will be permitted to render an opinion as to 

whether the exposure caused the plaintiff’s injury” in “sporadic accident” exposure case.); Bradford v. CITGO Petroleum Corp., 237 So. 3d 648, 666 (La. Ct. App.

2018) (affirming jury award where “the trial court was given significant circumstantial evidence that tied [plaintiffs’] exposures to the subject [chemical] spills”); 

Christian v. Gray, 65 P.3d 591, 606 (Okla. 2003) (“The method for determining 

the level of the toxin present in the environment may vary, and may include, 

when appropriate, the observations of those non-experts present when the exposure occurs.”). Cf. Heller v. Shaw Indus., Inc., 167 F.3d 146, 158 (3d Cir. 1999) 

(explaining that if plaintiffs had experienced “prompt reaction” to toxin rather 

than reporting reaction more than one year later, “this would be the type of temporal relationship that might reliably support a” finding of causation).

The Kansas Court of Appeals issued a decision that correctly applies the 

law and demonstrates the majority’s error. In Najera v. General Pest Control, LLC, 

the plaintiffs sued a pest control company after being exposed to pesticides 

sprayed in their workplace. 503 P.3d 1054, 1056, 1065 (Kan. Ct. App. 2021). 
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The district court granted judgment as a matter of law on the question of causation, and the appellate court reversed, holding there was a triable issue of fact 

based on an expert’s “testimony regarding potential effects of exposure, the 

MSDS [(material safety data sheet)] for the chemicals applied,” and a doctor’s 

diagnosis of conditions consistent with the known side effects of the chemicals

at issue. Id. The court further explained that “the Plaintiffs’ symptoms developed 

close in time to their exposure, which can be circumstantial evidence for establishing causation.” Id. at 1065. The court then explained at length why there was 

sufficient evidence of causation and why the defendant was wrong in stating that 

evidence of the dose was necessary:

The expert testimony here is not post hoc, ergo propter hoc reasoning. Dr. Henry’s and Dr. Goldstein’s testimony was not merely 

based on pure speculation, nor the mere premise that because one 

event occurred before another, the first must have caused the second. The pesticides used are known, the exposure is known, the potential effects of exposure are known, the Plaintiffs’ medical conditions and diagnoses are known, and the physical exams and lab 

work could support the medical diagnoses. . . . Here, there is no 

speculation that Plaintiffs were in the same location during, right 

after, and for prolonged periods after liquid chemicals were sprayed 

onto surfaces and into the air of the Office Building. Their exposure 

is not speculative; and to require them to list the weight or volume 

of exposure would preclude the submission of causation to the jury 

in almost every exposure case.

Defendants’ counsel argues that the Plaintiffs must prove the 

exact amount of exposure. If plaintiffs claiming negligence were required to prove the exact amount of poison, salmonella, radiation, 

or other toxin to which they were exposed, defendants could avoid 

all liability simply through failure to keep accurate records. In the 

case of a plaintiff working with toxins known to cause illness upon 

inhalation, under Defendants’ argument that plaintiff would need to 

prove the exact amount inhaled just to submit a case to the jury. 

What about a toddler who drinks from a bottle of poison? Under 

Defendants’ argument, the plaintiff would have to prove the exact 

amount consumed before submitting the case to the jury. Let us 
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assume the toddler did not take a measurement and the plaintiff 

forgot the amount in the bottle. In all such cases, a defendant could 

avoid a trial and total liability by alleging the amount of toxin ingested, inhaled, touched, or otherwise introduced was not known 

and thus causation could not be submitted to the jury. Such a result 

defies logic. Defendants are free to provide evidence, which might be 

compelling, contradicting Plaintiffs’ exposure allegations. But at 

some point in the fact-finding, it must be left up to the jury to determine the sufficiency of the evidence.

Id. at 1066–67.

The majority pays little attention to the rationale underlying Ranes and 

thus misapplies it here where the general and specific causation tests are unnecessary and unhelpful. This court should be cautious to avoid adopting principles “taken out of context, to formulate bright-line legal rules or conclude that 

reasonable minds cannot differ about factual causation.” Restatement (Third) 

§ 28 cmt. c, at 403. None of the concerns that motivated the creation of the bifurcated framework apply here. Graham Group concedes it had exclusive control 

of the building. At least eleven people in the building, including Uhler, were injured simultaneously and immediately after the defendant’s use of Draynamite. 

None of the Graham Group’s employees responding to the clogged drain or investigating the incident have any plausible explanation of harm other than Draynamite. Graham Group admitted to tenants in the building that the cause of 

harm was the use of Draynamite in the basement. Graham Group’s senior vice 

president of medical properties has opined that at least part of the cause of harm 

to tenants in the building was the use of Draynamite. Uhler’s experts opined that 

Uhler’s exposure to Draynamite caused her injury and that Uhler was uniquely 

vulnerable to Draynamite because of her preexisting medical conditions.
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All of this is sufficient to rule in Draynamite as a cause of injury, while no 

evidence rules Draynamite out. Indeed, the defendant admits Draynamite was a 

cause of injury. “[W]hile epidemiological evidence is helpful, it should not be held 

to be an absolute requirement in establishing causation.” Bloomquist v. Wapello 

County, 500 N.W.2d 1, 5 (Iowa 1993). As one commentator predicted, “Ranes

illustrates the principle that bad toxic tort claims make hard toxic tort causation 

rules that may later be applied to dismiss better but uncertain claims.” Steve C. 

Gold, The “Reshapement” of the False Negative Asymmetry in Toxic Tort Causation, 37 Wm. Mitchell L. Rev. 1507, 1575 (2011). That is true here. I respectfully 

dissent.

Oxley, J., joins this dissent.