[PUBLISH]

IN THE UNITED STATES COURT OF APPEALS

FOR THE ELEVENTH CIRCUIT

________________________

No. 17-10894

________________________

D.C. Docket No. 8:14-cv-01748-MSS-TGW

RHONDA WILLIAMS,

 Plaintiff-Appellant, 

versus

MOSAIC FERTILIZER, LLC,

 Defendant-Appellee.

________________________

Appeal from the United States District Court

for the Middle District of Florida

________________________

(May 14, 2018)

Before TJOFLAT and ROSENBAUM, Circuit Judges, and UNGARO,

* District 

Judge.

TJOFLAT, Circuit Judge:

In this toxic tort suit, Rhonda Williams appeals the District Court’s grant of 

summary judgment against her and in favor of Mosaic Fertilizer, LLC (“Mosaic”). 

 * Honorable Ursula Ungaro, United States District Judge for the Southern District of 

Florida, sitting by designation.

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Ms. Williams alleged that toxic substances emitted from a factory operated by 

Mosaic caused or exacerbated various medical conditions from which she suffers, 

including pulmonary hypertension, obstructive pulmonary disease, and other lung 

and non-lung-related conditions. The District Court, acting pursuant to Federal 

Rule of Evidence 702 and Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 

U.S. 579, 113 S. Ct. 2786 (1993), excluded the opinions of her proffered expert 

witness, Dr. Franklin Mink. Dr. Mink’s opinions were Ms. Williams’ only 

evidence as to general and specific causation. Therefore, upon excluding Dr. 

Mink’s opinions, the Court granted Mosaic’s motion for summary judgment with 

respect to all causes of action requiring a showing of causation. The District Court 

also excluded Ms. Williams’ testimony about the value and salability of her home, 

and, in the absence of other evidence showing that the value of her home was 

diminished by Mosaic’s alleged contamination of it, granted summary judgment in 

favor of Mosaic as to the remaining cause of action. 

After careful review of the record, and with the benefit of oral argument, we 

affirm.

I.

Ms. Williams was born in 1967 and has lived her entire life at the same 

residence in Tampa, Florida. The home, located in the Progress Village 

neighborhood, is approximately three miles from Mosaic’s Riverview plant. She 

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alleged that she suffers from G6PD associated pulmonary hypertension, asthmarelated restrictive pulmonary function, obstructive pulmonary disease, airway 

remodeling, lower lung scarring, allergic reactions, side effects from therapeutic 

treatments for her lung disorders, extreme fatigue, intense abdominal pain, and 

diabetes. She alleged that chemicals emitted from Mosaic’s facility caused, 

contributed to, or exacerbated these conditions. 

According to Ms. Williams, Mosaic’s operations in and around the 

Riverview plant involve the production and handling of a number of chemicals, 

including sulfuric acid, phosphoric acid, fluoride, and ammoniate phosphates. She 

averred that Mosaic’s production of these substances produces emissions, in the 

form of dust and particulates, of toxic substances that permeate the ambient air in 

and around her home and community. Some of these include various types of 

particulate matter, arsenic, cadmium, chromium, lead, manganese, nickel, 

phosphorous, and zinc. 

In the past, the U.S. Environmental Protection Agency (“EPA”) and the 

Hillsborough County Environmental Protection Commission have promulgated 

data taken from monitoring stations at or near the Riverview plant showing that 

sulfur dioxide levels in the ambient air at those stations exceeded the National 

Ambient Air Quality Standard (“NAAQS”) of 75 parts per billion. Additionally, 

Hillsborough County at large has been found in violation of the NAAQS standard, 

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and the ambient air at a monitoring station at the Riverview plant has on multiple 

occasions been found in violation of Florida’s more lenient standard of 100 parts 

per billion. In addition to these sulfur dioxide emissions, monitoring data at a 

testing site located near the Riverview facility and Ms. Williams’ neighborhood 

showed, on at least one occasion, that the concentration of PM10 respirable 

particulates, a respiratory irritant, exceeded the national standard of 150 

micrograms based on a one-hour average. 

Ms. Williams alleged six causes of action under Florida law in separate 

counts: negligence, gross negligence, strict liability, strict liability failure to warn, 

strict liability for “prohibited discharge” of pollutants, and medical monitoring and 

environmental testing.1

 To establish general and specific causation, she turned to 

Dr. Mink. Dr. Mink, an experienced toxicologist, prepared and furnished a 

summary of his “preliminary expert opinions.” 

The report contained sixteen pages of analysis, including a description of 

Ms. Williams’ medical background, information on G6PD deficiency, and a set of 

“preliminary expert opinions” reached “with a reasonable degree of scientific 

certainty.” Those opinions were:

1) Rhonda Williams has been exposed to significant quantities of 

regulated pollutants and hazardous materials from both direct and 

 

1 The District Court had diversity jurisdiction under 28 U.S.C. § 1332. Mosaic removed 

the action from Florida state court to the Middle District of Florida in accordance with 28 U.S.C. 

§§ 1332, 1441, and 1446.

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fugitive sources as a result of Mosaic’s operations including 

phosphogypsum mining, processing, storage, transportation and waste 

handling operations over her lifetime residence in Prospect Village, 

Florida primarily through inhalation and dermal exposures.

2) Rhonda Williams has developed significant adverse health effects 

as a result of these hazardous exposures including G6PD associated 

pulmonary hypertension and obstructive pulmonary disease resulting 

in a diminished quality of life and potentially reduced life span.

3) Rhonda Williams has developed significant adverse health effects 

as a result of secondary effects from therapeutic agents used to treat 

her diseases/symptoms resulting from these exposures further 

diminishing her quality of life and threatening her long-term physical 

and mental wellbeing.

At the end of the analysis section of the report, Dr. Mink listed fifty-eight 

references. These consisted of various empirical studies, website references, and 

regulatory documents. Within the body of the analysis, he cited another eighteen 

sources. None were pin-cited or otherwise annotated to show which portions 

supported each conclusion. 

After Dr. Mink submitted his preliminary report, Mosaic deposed him. 

After the deposition, Mosaic moved to exclude Dr. Mink’s testimony under 

Federal Rule of Evidence 702 and Daubert. Mosaic also moved for summary 

judgment as to all of Ms. Williams’ claims. Ms. Williams filed responses in 

opposition. Without conducting a Daubert hearing, the District Court granted 

Mosaic’s motion to exclude Dr. Mink’s opinion testimony. The Court explained 

its decision thusly:

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[T]he Court concludes that Dr. Mink’s expert report and proposed 

testimony cannot survive a Daubert challenge. Critically, Dr. Mink 

has neglected the hallmark of the science of toxic torts—the dose 

response relationship. In and of itself, this is a sufficient basis for 

excluding his testimony. He also unjustifiably relies on regulatory 

standards to determine dose, infers facts from studies that contradict 

his conclusions, fails to consider the background risk for Plaintiff’s 

illnesses, fails to rule out alternative potential causes of Plaintiff’s 

illnesses, and renders speculative and conclusory opinions about 

Plaintiff’s exposure to Mosaic’s emissions. All in all, it is clear that 

Dr. Mink has failed to adhere to the methodology expected of 

toxicologists in toxic tort cases, and he has not demonstrated a reliable 

basis for his opinions.

In its order granting the motion, the Court comprehensively analyzed Dr. 

Mink’s report and methodology, identifying and explaining its primary concerns 

and others. Because Dr. Mink was Ms. Williams’ sole source of causation 

evidence, the Court, in the same order, granted Mosaic’s motion for summary 

judgment as to all claims requiring a showing of causation. 

When the dust settled, Ms. Williams had one remaining claim: her 

“prohibited discharge” claim. This claim was brought under Section 376.313 of 

the Florida Statutes, which confers a private right of action on citizens who suffer 

damage from a discharge of materials in violation of Florida’s environmental 

standards. For this claim, Ms. Williams alleged that the pollutants and dust from 

the Riverview plant diminished the value of her home to the point where it was 

unsellable. Ms. Williams planned to testify on her own behalf as to the value of 

her home. According to her responses to Mosaic’s interrogatories, Ms. Williams 

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believed and planned to testify that “the property has no present value as any sale 

would require the disclosure of the toxins found in and around the home and 

neighborhood, . . . which came directly from Mosaic Fertilizer.” 

As the case proceeded towards trial, Mosaic moved to exclude Ms. 

Williams’ valuation testimony, arguing that such testimony was beyond her 

expertise as a lay witness, irrelevant, and substantially more prejudicial than 

probative because it called for heavy speculation and conjecture. The District 

Court granted Mosaic’s motion. Upon consideration of her discovery responses 

and prior testimony, it found that Ms. Williams’ testimony “lack[ed] foundation 

and [wa]s purely speculative.” Then, in the same order, the District Court granted 

summary judgment for Mosaic sua sponte as to the remaining claim. The Court 

observed that Ms. Williams “was on notice that she was required to come forth 

with all her evidence regarding the damages element of the Section 376.313 

claim,” yet failed to produce anything more than her own inadmissible testimony. 

Thus, the Court found that summary judgment was warranted as to her “prohibited 

discharge” claim on account of her failure to prove any damages resulting from the 

discharge. The Court therefore entered judgment in favor of Mosaic. Ms. 

Williams timely appealed. 

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II.

We review the District Court’s grant of summary judgment de novo. Doe v. 

Sch. Bd., 604 F.3d 1248, 1253 (11th Cir. 2010). We begin with the exclusion of 

Dr. Mink’s opinion testimony. Federal Rule of Evidence 702 makes expert 

opinion testimony admissible only “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 reliably to the facts of 

the case.” As interpreted by the Supreme Court in Daubert, this requires the trial 

court “to act as a gatekeeper to insure that speculative and unreliable opinions do 

not reach the jury.” McClain v. Metabolife Int’l, Inc., 401 F.3d 1233, 1237 (11th 

Cir. 2005). To properly serve as a gatekeeper, the trial court must perform “a 

preliminary assessment of whether the reasoning or methodology underlying the 

testimony is scientifically valid and of whether that reasoning or methodology 

properly can be applied to the facts in issue.” Daubert, 509 U.S. at 593–94, 113 

S.Ct. at 2796. When doing so, “the court must consider the testimony with the 

understanding that the burden of establishing qualification, reliability, and 

helpfulness rests on the proponent of the expert opinion.” McClain, 401 F.3d at 

1238 (quotations omitted) (alterations omitted) (quoting United States v. Frazier, 

387 F.3d 1244, 1260 (11th Cir. 2004)).

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“The trial judge must have considerable leeway in deciding in a particular 

case how to go about determining whether particular expert testimony is reliable” 

under Daubert. Kumho Tire Co. v. Carmichael, 526 U.S. 137, 152, 119 S. Ct. 

1167, 1176 (1999). Hence, we review a district court’s Daubert rulings for abuse 

of discretion. Gen. Elec. Co. v. Joiner, 522 U.S. 136, 143, 118 S. Ct. 512, 517

(1997). We will affirm unless the court “has made a clear error of judgment, or 

has applied an incorrect legal standard.” Piamba Cortes v. Am. Airlines, Inc., 177 

F.3d 1272, 1306 (11th Cir. 1999) (quotations omitted).

Here, the District Court did not abuse its discretion in excluding Dr. Mink’s 

opinions. The Court comprehensively analyzed Dr. Mink’s report and deposition 

testimony, carefully reviewed the literature upon which he relied in forming his 

causation opinions, and determined that his methodology was undermined by 

multiple defects.

2 We find no error in the Court’s analysis and no need to discuss 

 

2 Ms. Williams argues that the District Court abused its discretion in requiring Dr. Mink 

to demonstrate both general and specific causation, as opposed to just specific causation. This 

Court has delineated two categories of toxic tort cases: “those cases in which the medical 

community generally recognizes the toxicity of the drug or chemical at issue,” and “those cases 

in which the medical community does not generally recognize the agent as both toxic and 

causing the injury the plaintiff alleges.” McClain, 401 F.3d at 1239. In the former cases, “[t]he 

court need not undertake an extensive Daubert analysis on the general toxicity question.” Id. In 

the latter, “the Daubert analysis covers not only the expert’s methodology for the plaintiffspecific questions about individual causation but also the general question of whether the drug or 

chemical can cause the harm plaintiff alleges.” Id. (emphasis in original). 

In Ms. Williams’ view, the scientific sources she and Dr. Mink cite demonstrate that it is 

generally accepted in the scientific community that the toxins emitted by Mosaic’s facility 

“cause the exact type of harm alleged by Ms. Williams.” The District Court treated the toxicity 

of the substances as not generally accepted because it found that “Plaintiff has failed to offer any 

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every aspect of its comprehensive assessment anew. However, three of the most 

significant problems with Dr. Mink’s methodology are illustrative: first, his failure 

to properly assess dose-response with regard to Ms. Williams; second, his failure 

to meaningfully rule out other potential causes of Ms. Williams’ medical 

conditions; and third, his failure to account for the background risk of her 

conditions. 

With respect to dose-response, we have explained the importance of the 

dose-response assessment in these sorts of cases before. “When analyzing an 

expert’s methodology in toxic tort cases, the court should pay careful attention to 

the expert’s testimony about the dose-response relationship.” McClain, 401 F.3d 

at 1241. This attention is due because dose-response is “the hallmark of basic 

toxicology.” Id. at 1242. Stripped to its bare essentials, a dose-response 

assessment estimates scientifically “the dose or level of exposure at which [the 

substance at issue] causes harm.” Id. at 1241. 

 

evidence of general acceptance within the medical community that sulfur dioxide and the other 

constituents from the Mosaic emissions cause the illnesses from which she claims she suffers.” 

We need not and do not decide this question. Setting general causation aside, to establish 

specific causation, Dr. Mink would still have to reliably calculate whether Ms. Williams was 

“exposed to enough of the toxin to cause the alleged injury,” McClain, 401 F.3d at 1239, which 

he could have done only after reliably calculating how much exposure would have adversely 

affected her. In other words, under either category, he still needed to perform or rely upon a 

methodologically sound dose-response assessment specifically relevant to Ms. Williams. As 

discussed, his dose-response analysis was deeply flawed. See infra. Thus, no matter whether the 

case was treated as a category one case or a category two case, the District Court’s exclusion of 

his opinion testimony was not an abuse of discretion. 

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Here, Dr. Mink conceded he never conducted an independent dose

calculation specific to Ms. Williams. Instead, he relied on two academic studies 

measuring the ambient air concentration of pollutants in the area in which Ms. 

Williams lived to estimate the dose she received and on the EPA’s NAAQS 

regulatory standards to establish the dose threshold above which Ms. Williams’ 

conditions would likely result from her exposure. As the District Court correctly 

observed, his reliance on these sources was methodologically problematic in 

multiple respects. Among the most glaring problems was the fact that both 

academic studies he relied upon directly contradicted his causation opinions. For 

example, one study concluded that “phosphate fertilizer plants make minor 

contribution to the ambient levels of HAP metals compared to other sources for the 

general population in the Tampa Bay area,” and that the air concentration of the 

various pollutants studied fell hundreds of times below levels that would present 

health risks to the public. Hsing-Wang Li, et al., Impacts of Hazardous Air 

Pollutants Emitted from Phosphate Fertilizer Production Plants on Their Ambient 

Concentration Levels in the Tampa Bay Area, 8 Air Qual. Atmos. Health 453, 453, 

464 (2015). 

This cuts directly against his opinion that Mosaic’s emissions adversely 

affected Ms. Williams. And although Ms. Williams argues that Dr. Mink relied on 

the studies’ underlying data while disagreeing with their ultimate conclusions, Dr. 

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Mink and Ms. Williams never clearly explained why Dr. Mink reached a different 

conclusion with regard to Mosaic’s contribution to pollution in Ms. Williams’ 

community or why his conclusion was correct and the authors’ incorrect until after

the District Court ruled on the admissibility of his testimony. Thus, he failed to 

squarely present the basis for his disagreements to the District Court until after the 

fact. See Kilpatrick v. Breg, Inc., 613 F.3d 1329, 1341 (11th Cir. 2010) (holding 

the district court did not abuse its discretion in excluding expert testimony, when 

the expert “had ample opportunity to identify all of the bases for his conclusions 

and to explain his methodology in reaching those conclusions” yet failed to do so). 

Moreover, assuming for the sake of argument that Dr. Mink’s dose estimates 

were methodologically sound, he failed to demonstrate a scientific basis for 

concluding that those exposure levels would likely produce, contribute to, or 

exacerbate Ms. Williams’ conditions. For example, he estimated that Ms. 

Williams was exposed to sulfur dioxide at a long-term concentration rate 

exceeding 75 parts per billion (though he never reached a more specific number 

than this), and, based on her purported heightened sensitivity to exposure and the

NAAQS standard’s calculation to protect sensitive members of the population, 

assumed that exposure at or above this level was likely to cause her conditions. He 

based this sweeping assumption on the fact that the 75 parts per billion number is 

the primary emissions standard set by the EPA for sulfur dioxide in its NAAQS 

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standard. However, this Court has previously explained the potential 

methodological perils of relying, at face value, on regulatory emissions levels to 

establish causation. See McClain, 401 F.3d at 1249 (observing that face-value 

reliance on regulatory dose standards raises a “subtle methodological issue”). 

The biggest problem stems from the potential difference in purpose between 

regulatory standards and toxicological dose-response calculations: regulatory 

standards often build in considerable cushion in order to account for the most 

sensitive members of the population and prophylactically protect the public (in 

other words, they are protective), while dose-response calculations aim to identify 

the exposure levels that actually cause harm (in other words, they are predictive). 

See id. at 1249–50 (explaining the different calculations and burdens of proof 

employed by regulatory agencies in setting exposure standards for the general 

public, as compared to those employed by toxicologists in calculating doseresponse). 

But Ms. Williams argues that Dr. Mink’s facial reliance on NAAQS

standards in this case is different, because those standards are predictive. She 

contends that the EPA’s assessments reveal that “exposure to 75 ppb of [sulfur 

dioxide] causes (not may cause or can cause, but actually does cause) respiratory 

morbidity,” and that the standards result from “dose-response assessments based 

on human studies.” (Emphasis in original). In other words, relevant dose-response 

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assessments are built into the standard. However, the EPA’s own regulations 

require the agency to establish NAAQS levels ensuring “protection of public health 

with an adequate margin of safety,” even if this means setting emissions thresholds 

at a level at which “the risk is not precisely identified as to nature or degree.” 75 

Fed. Reg. 35520–01 at *35521 (June 22, 2010). Further, Dr. Mink stated that he 

relied upon dose-response calculations included in the EPA’s Integration Risk 

Information System (“IRIS”), which the EPA relies upon in setting NAAQS 

standards. But the EPA has expressly stated that the dose-response assessments in 

IRIS are not suited to predicting the incidence of exposure-caused disease in 

humans: 

In general, risk values, such as those on IRIS, cannot be used to 

predict the actual incidence of human disease or the type of effects 

chemical exposures may have on humans. This is due to the 

numerous uncertainties involved in risk assessment, including those 

associated with extrapolations from animal data to humans and from 

high experimental doses to lower environmental exposures. The 

organs affected and the types of adverse effects resulting from 

chemical exposure may differ between study animals and humans. In 

addition, many factors besides exposure to a chemical influence the 

occurrence and extent of human disease.

53 Fed. Reg. 20162–02 at *20163 (June 2, 1988). It is for precisely these reasons 

that we have cautioned against facial reliance on regulatory standards as a 

substitute for scientifically rigorous dose-response assessments. And while it is 

true that the EPA’s studies “led to the conclusion that there is a causal relationship 

between respiratory morbidity and short-term exposure to SO2,” the existence of a 

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generalized “causal relationship” was not the operative issue. What mattered was 

whether the EPA’s data provided a reasonably specific calculation as to the 

exposure amounts required to cause Ms. Williams’ conditions upon which Dr. 

Mink could reasonably rely in forming his opinions. 

Though Ms. Williams alleged that, on account of her G6PD, she is more 

sensitive to exposure than the average member of the general public, Dr. Mink 

never attempted to quantify how much more sensitive she is. As the District Court 

observed, at the time it made its ruling, he did “not cite with specificity which 

studies and peer-reviewed literature demonstrate the increased sensitivity of 

individuals with G6PD. Consequently, the Court [could] not evaluate those 

sources and determine whether they are based on reliable methodologies or

otherwise support his opinions.” Without this, he could not rely on NAAQS 

standards, because he never adequately established whether her sensitivity to 

exposure placed her within the class of persons who would likely suffer from 

exposure at the ranges he estimated, let alone whether the standards were 

predictive or protective with regard to her. 

To be clear, we have never required an expert to “give precise numbers 

about a dose-response relationship,” McClain, 401 F.3d at 1241 n.6, and we do not 

do so here. But we do require an expert to lay a “reliable groundwork for 

determining the dose-response relationship.” Id. at 1241. Here, Ms. Williams bore 

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the burden of demonstrating to the District Court that Dr. Mink’s facial reliance on 

NAAQS standards was methodologically sound. In light of their protective nature 

and the EPA’s express warnings that those standards—and the IRIS assessments 

upon which they were formulated—are unreliable predictors of conditions in 

humans, we are not persuaded that the District Court erred in determining that Ms. 

Williams failed to meet that burden.3

 

Further, the District Court correctly observed that Dr. Mink’s report suffered 

from methodological errors related to the cause of Ms. Williams’ conditions. Dr. 

Mink failed to meaningfully rule out other potential causes of Ms. Williams’ 

 

3 We further note that both in the District Court and before this Court, when put to the 

task of identifying the bases of Dr. Mink’s dose-response conclusions with specificity, Dr. Mink 

and Ms. Williams obfuscated. We granted leave for counsel to file a one-page letter brief with 

citations in the record to authorities relied upon by Dr. Mink which employed predictive, rather 

than protective, analyses. In response, we received an eleven-page, shotgun-style brief with 

citations to dozens of regulatory documents comprising hundreds of pages. Most had nothing to 

do with studies—predictive or protective—at all, many included only estimated “fatal” doses of 

the various substances discussed (and nothing about doses that could lead to Ms. Williams’ 

conditions), many of the studies were concerned solely with the carcinogenic effects of those 

substances (Ms. Williams does not have cancer and the carcinogenicity of the substances is not 

otherwise at issue in this case), many were not in the record below, and none were pin-cited. 

Dr. Mink’s expert report submitted in the District Court fared no better. At the end of the 

analysis section of his report, Dr. Mink listed 58 references. These consisted of various 

empirical studies, website references, and regulatory documents. Within the body of the 

analysis, he cited another 18 sources. Included with none of those 76 sources were endnotes, pin 

cites, or any other explanations as to what information Dr. Mink gained from those references or 

what sources supported what conclusions. And certainly nothing pointed the District Court to 

the underlying dose-response assessments Dr. Mink purportedly relied upon. It was only after 

the District Court excluded his testimony that Dr. Mink filed a more concise statement 

concerning the bases of his conclusions. Thus, to the extent the District Court was limited in its 

assessment of Dr. Mink’s methodology by his and Ms. Williams’ obfuscation in explaining the 

bases of his conclusions, it did not err in considering only that which was squarely before it. See

Kilpatrick, 613 F.3d at 1341 (holding the district court did not abuse its discretion in excluding 

expert testimony, when the expert “had ample opportunity to identify all of the bases for his 

conclusions and to explain his methodology in reaching those conclusions” yet failed to do so).

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conditions and symptoms. Indeed, one of the studies heavily relied upon by Dr. 

Mink determined that environmental factors and emissions by other facilities 

caused the vast majority of pollution in the area in which Ms. Williams lived. Li, 

supra, at 453. Yet Dr. Mink never addressed how or even if he ruled out those 

other potential contributors in reaching his conclusion that Mosaic’s facility caused 

Ms. Williams’ alleged harms. Nor did he, in his report or his deposition, eliminate 

or even address factors not related to air quality, such as Ms. Williams’ obesity, 

allergies, lifestyle, exposure to secondhand smoke, or possible genetic 

predisposition. When asked about how he eliminated other potential causes of Ms. 

Williams’ conditions, Dr. Mink stated:

Oh, I think we eliminated causes based on their probability. I mean, 

they were so low in comparison that—that we can eliminate them. 

Are they totally nonexistent, absolutely not, and I think I testified to 

that earlier.

However, Dr. Mink never provided the District Court or this Court with any 

probability studies regarding those potential causes, and his expert report never 

referenced those probabilities. 

Thus, although he made passing references to the purported “low” 

probability of those other causes, Dr. Mink never provided the District Court with 

any scientific basis upon which he relied in concluding that the likelihood that 

various other potential factors caused Ms. Williams’ conditions was low enough to 

reasonably rule them out. The law does not require the District Court to take him 

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at his word. See Joiner, 522 U.S. at 146 (“[N]othing in either Daubert or the 

Federal Rules of Evidence requires a district court to admit opinion evidence that is 

connected to existing data only by the ipse dixit of the expert.”).4

 

Nor does it appear Dr. Mink meaningfully accounted for the background risk 

of Ms. Williams’ conditions. The background risk “is the risk a plaintiff and other 

members of the general public have of suffering the disease or injury that plaintiff 

alleges without exposure to the drug or chemical in question.” McClain, 401 F.3d 

at 1243 (emphasis in original). When asked during his deposition, Dr. Mink did

not demonstrate specific knowledge of the general prevalence of Ms. Williams’ 

various conditions:

Q: What is the prevalence of pulmonary hypertension in the 

population, the general population?

A: I don’t recall. It’s not large.

Q: What is the prevalence of obstructive pulmonary disease in the 

population?

A: I don’t recall specifically, but it’s significant.

These answers do not indicate serious consideration of the background risk. And

while his deposition alone may not authoritatively indicate that he failed to account 

 

4 To the extent Ms. Williams argues that Dr. Mink could have better cited the specific 

authorities in support of his opinions at a Daubert hearing, we conclude that the District Court 

did not abuse its discretion in ruling on the admissibility of his opinion testimony without 

conducting such a hearing. Dr. Mink filed his expert report and testified at a day-long 

deposition, and Ms. Williams’ counsel had the opportunity to cite those authorities with greater 

specificity in her response to Mosaic’s motion to exclude Dr. Mink’s testimony. Thus, Dr. Mink 

and Ms. Williams had sufficient opportunity to present those bases to the Court before it decided 

the question. This is true with regard to both his dose-response assessments and his assessments 

regarding other potential causes. 

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for it, he also failed to address background risk in his report or elsewhere. Thus, 

the evidence before the District Court at the time it considered Mosaic’s Daubert 

motion does not indicate he meaningfully accounted for background risk. 

In conclusion, Dr. Mink failed to meaningfully address other potential 

causes of Ms. Williams’ conditions or even the background risk of those 

conditions. This fundamental methodological failure undermined the soundness of 

his causation opinions, and the District Court was therefore right to exclude those 

opinions as unsound. 

III.

We review the District Court’s exclusion of lay opinion testimony pursuant 

to the Federal Rules of Evidence for abuse of discretion. United States v. Jeri, 869 

F.3d 1247, 1259 (11th Cir. 2017), cert. denied, 138 S. Ct. 529 (2017). Lay opinion 

testimony must be “(a) rationally based on the witness’s perception; (b) helpful to 

clearly understanding the witness’s testimony or to determining a fact in issue; and 

(c) not based on scientific, technical, or other specialized knowledge within the 

scope of Rule 702.” Fed. R. Evid. 701.

In general, “an owner of property is competent to testify regarding its 

value.” Neff v. Kehoe, 708 F.2d 639, 644 (11th Cir. 1983). However, “where the 

owner bases his estimation solely on speculative factors, the owner’s testimony 

may be of such minimal probative force to warrant a judge’s refusal even to submit 

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the issue to the jury.” Kestenbaum v. Falstaff Brewing Corp., 514 F.2d 690, 699 

(5th Cir. 1975), modified on other grounds en banc, 575 F.2d 464 (5th Cir. 1978).5

 

The District Court did not abuse its discretion in excluding Ms. Williams’ 

lay valuation testimony. Opinions by lay witnesses must be derived from personal 

knowledge or experience. See Fed. R. Evid. 701 Advisory Committee Notes, 2000 

Amendments. Here, Ms. Williams does not allege she tried to sell her home or 

spoke with an appraiser or real estate agent to ascertain its value. Indeed, she 

concedes she did not. When asked by Mosaic in its interrogatories to provide “any 

criteria, rationale, bases, or grounds” for calculating her valuation estimate of zero, 

she stated:

Ms. Williams contends the property has no present value as any sale 

would require the disclosure of the toxins found in and around the 

home and neighborhood, as previously produced in this action, which 

came directly from Mosaic Fertilizer. Ms. Williams does not believe 

that a rational, educated person, who had knowledge of the presence 

of the toxic emissions and/or their long-term health effects would 

want to acquire residential property in her neighborhood; and that her 

property is damaged by the stigma associated with the continual and 

on-going exposure to Sulfur Dioxide, Arsenic, Cadmium, Chromium, 

Barium, Radioactive isotopes and other hazardous air pollutants. 

Under the law, a seller in Florida must disclose any facts to a potential 

buyer that would affect the value of the property. Here, Ms. Williams 

would be required to disclose the presence of Sulfur Dioxide, 

Radioactive isotopes and other hazardous air pollutants found at her 

property and in and around her neighborhood.

 

5 We have adopted as binding “the decisions of the United States Court of Appeals for the 

Fifth Circuit, as that court existed on September 30, 1981, handed down by that court prior to 

close of business on that date.” Bonner v. City of Prichard., 661 F.2d 1206, 1209 (11th Cir. 

1981) (en banc).

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This is pure speculation. That a home is contaminated does not necessarily make it 

valueless. In fact, Ms. Williams testified from her own knowledge that homes in 

her neighborhood, including one on the same block as hers, had recently been sold. 

This directly refuted her contention that the value of her home was zero. Thus, 

despite the general rule that homeowners may testify as to the value of their homes, 

Ms. Williams’ testimony was inadmissible because it would not have been based 

on personal knowledge. The District Court therefore did not err in excluding her 

testimony for lack of foundation. 

Ms. Williams argues in the alternative that even if exclusion of her valuation 

testimony was proper, she should have been allowed to present evidence of 

“contamination damages,” including “destruction and remediation damages.” But

Ms. Williams did not allege any functional damage to her home or cognizable 

economic losses resulting from the contamination of her home, such as repair 

expenses. Instead, she sought “destruction damages (which is full value for 

permanent damage caused by the contamination).” This is just another way of 

stating that her home’s value was diminished as a result of pollutants from 

Mosaic’s facility. Hence, her testimony would not have been any different under a 

theory of “stigma damages” (the diminution in value of her home from having to 

disclose the presence of contaminants in her neighborhood) or a theory of 

“contamination damages” (the diminution in value of her home as a result of its 

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actual contamination with pollutants). Therefore, the District Court committed no 

error in excluding her testimony. 

IV.

We accordingly affirm the District Court’s exclusion of Dr. Mink and Ms. 

Williams’ opinion testimony and its subsequent grants of summary judgment in 

favor of Mosaic. 

AFFIRMED. 

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