[DO NOT PUBLISH]

IN THE UNITED STATES COURT OF APPEALS

FOR THE ELEVENTH CIRCUIT

________________________

No. 18-15065

Non-Argument Calendar

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D.C. Docket No. 8:17-cv-00990-JDW-AEP

JOHN MCCASLAND, 

 Plaintiff-Appellant,

 versus

PRO GUARD COATINGS, INC., 

 Defendant-Appellee.

________________________

Appeal from the United States District Court

for the Middle District of Florida

________________________

(January 23, 2020)

Before WILSON, ROSENBAUM, and ANDERSON, Circuit Judges.

PER CURIAM: 

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In this products-liability lawsuit, John McCasland contends that he suffered 

permanent injuries from using “Liquid Roof,” a product manufactured and sold by 

Pro Guard Coatings, Inc. (“Pro Guard”). From 2010 to 2013, McCasland used 

Liquid Roof as intended, and in compliance with all safety instructions, to repair 

aging or damaged roofs for his work as a Recreational Vehicle restoration specialist. 

He began to suffer mysterious health problems in 2012, first presenting with an 

arrhythmia. In 2013, he began to experience unexplained and involuntary 

movements of his tongue and mouth, which worsened over time despite medical 

treatment. Then, in 2014, a physician diagnosed the involuntary movements as 

oromandibular dystonia, which McCasland was told was likely permanent. 

McCasland then filed a counseled lawsuit alleging that Pro Guard was liable in 

negligence or strict liability for failing to adequately warn of the risks posed by 

Liquid Roof.

After discovery, the district court granted summary judgment to Pro Guard. 

Summary judgment was appropriate, according to the court, because McCasland 

offered no evidence from which a reasonable jury could find, within a reasonable 

degree of medical certainty, that Liquid Roof was capable of causing and did in fact 

cause his medical conditions. Specifically, the court found that McCasland was 

required, but failed, to present expert testimony to establish that causal connection. 

McCasland now appeals. 

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We review de novo the district court’s grant of summary judgment and apply

the same standard used by the district court. Burton v. Tampa Hous. Auth., 271 F.3d 

1274, 1276 (11th Cir. 2001). Summary judgment is appropriate “if the movant 

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

entitled to judgment as a matter of law.” Fed. R. Civ. P. 56(a). In evaluating a 

summary-judgment motion, “all evidence and factual inferences reasonably drawn 

from the evidence” are viewed “in the light most favorable to the non-moving 

party”—here, McCasland. Burton, 271 F.3d at 1277. “But while all reasonable 

inferences must be drawn in favor of the nonmoving party, an inference based on 

speculation and conjecture is not reasonable.” Hinson v. Bias, 927 F.3d 1103, 1115 

(11th Cir. 2019) (quotation marks omitted).

In diversity cases, federal courts apply the substantive law of the state in which 

the case arose—here, Florida. Pendergast v. Sprint Nextel Corp., 592 F.3d 1119, 

1132–33 (11th Cir. 2010). Under Florida Law, a claim for failure to warn, whether 

in negligence or strict liability, requires a plaintiff to show “(1) that the product 

warning was inadequate; (2) that the inadequacy proximately caused her injury; and 

(3) that she in fact suffered an injury from using the product.” Eghnayem v. Boston 

Sci. Corp., 873 F.3d 1304, 1321 (11th Cir. 2017). This appeal concerns the third 

element only. 

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To prove causation in a toxic-tort case, a plaintiff generally must show both 

“general causation” and “specific causation.” See McClain v. Metabolife Int’l, Inc., 

401 F.3d 1233, 1239 (11th Cir. 2005). General causation refers to “whether the drug 

or chemical can cause the harm plaintiff alleges.” Id. Specific causation refers to 

“whether the plaintiff has demonstrated that the substance actually caused injury in 

her particular case.” Guinn v. AstraZeneca Pharm. LP, 602 F.3d 1245, 1248 n.1 

(11th Cir. 2010). To show general causation, the plaintiff may offer proof that “the 

medical community recognizes that the agent causes the type of harm a plaintiff 

alleges.” McClain, 401 F.3d at 1239. But even where the medical community 

generally recognizes that the agent causes the type of harm a plaintiff alleges, the 

plaintiff still must offer proof that the agent was a substantial factor in causing the 

plaintiff’s injuries. See id.; Guinn, 602 F.3d at 1256 (describing Florida’s 

“substantial factor” test for proving causation).

Moreover, in cases where a jury is asked to assess complex medical or 

scientific issues outside the scope of a layperson’s knowledge, an expert’s testimony 

is required. See Chapman v. Procter & Gamble Distrib., LLC, 766 F.3d 1296, 1316 

(11th Cir. 2014) (stating that, to prove a product caused the plaintiff’s injury, the 

plaintiff was “required to have Daubert-qualified, general and specific-causationexpert testimony that would be admissible at trial to avoid summary judgment” 

(emphasis in original)); McClain, 401 F.3d at 1237 (proving that the toxicity of an 

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agent caused the plaintiff’s injuries “requires expert testimony”); Shepard v. 

Barnard, 949 So. 2d 232, 233 (Fla. Dist. Ct. App. 2007) (approving trial court’s grant 

of summary judgment against plaintiff after excluding plaintiff’s medical experts’ 

testimony, because the doctors were needed “to provide opinions regarding any 

causal link between the alleged injury and the medical treatment”). Expert testimony 

was required in this case because the question whether Liquid Roof can and did cause 

the harm McCasland alleges “concerns matters that are beyond the understanding of 

the average lay person.” United States v. Frazier, 387 F.3d 1244, 1262 (11th Cir. 

2004). 

Here, the district court properly granted summary judgment to Pro Guard

because McCasland failed to create a genuine issue of a material fact regarding 

causation. Guinn, 602 F.3d at 1256. To be sure, McCasland produced some evidence 

that Liquid Roof was hazardous. Specifically, his sole expert, Dr. Justin White, a 

biochemist, opined that Liquid Roof was “particular[ly] hazardous” based on an 

analysis of its component chemicals. McCasland also points to the warning label on 

the product, which advised that it “[m]ay affect the brain or nervous systems causing 

dizziness, headache, or nausea,” and that “[r]eports have associated repeated and 

prolonged occupational overexposure to solvents with permanent brain and nervous 

system damage.” But, even so, McCasland’s evidence fails to show that Liquid Roof, 

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even if it’s generally hazardous and can cause nervous system damage, is capable of 

causing the particular condition—oromandibular dystonia—of which he complains. 

More importantly, McCasland failed to offer any expert testimony to establish 

specific causation—that Liquid Roof did in fact cause his medical condition. 

Dr. White admitted in his deposition that it was outside of his training to provide an 

opinion regarding causation for a condition and that he would not be providing an 

opinion regarding the cause of McCasland’s condition. Additionally, McCasland’s 

physicians offered no opinion as to what caused his oromandibular dystonia or other 

symptoms. Because the record contains no expert testimony of specific causation, 

the district court properly granted summary judgment. See Chapman, 766 F.3d at 

1316 (stating that the plaintiffs “were required to have Daubert-qualified, general 

and specific-causation-expert testimony that would be admissible at trial to avoid 

summary judgment”); Guinn, 602 F.3d at 1256 (granting summary judgment in the 

absence of expert testimony as to specific causation); McClain, 401 F.3d at 1237

(stating that proving causation in a toxic tort case “requires expert testimony”). 

In his pro se brief on appeal, which we liberally construe, see Timson v. 

Sampson, 518 F.3d 870, 874 (11th Cir. 2008), McCasland argues that a reasonable 

jury could find a causal nexus as a matter of logical reasoning. He points out that he 

developed medical problems only after using Liquid Roof and breathing its fumes 

regularly and that his symptoms matched the symptoms described on the product’s 

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warning label. We do not doubt the symptoms McCasland describes or his sincere 

belief that his exposure to Liquid Roof caused his health problems. But his lay 

opinion on the matter is not sufficient to withstand summary judgment because the 

question whether Liquid Roof caused his injuries is a matter “beyond the 

understanding of the average lay person.” Frazier, 387 F.3d at 1262. On this record, 

too much speculation is required for a jury to conclude that Liquid Roof more likely 

than not was a substantial factor in causing the McCasland’s injuries. See McClain, 

401 F.3d at 1239; Hinson, 927 F.3d at 1115 (“[A]n inference based on speculation 

and conjecture is not reasonable.”). And while McCasland states that he has engaged 

in extensive research on the issue, we see no indication that he could meet the 

requirements to qualify as an expert witness. See Fed. R. Evid. 702. 

McCasland compares this case to cases brought against tobacco companies and 

argues that, in light of that comparison, his proof should be considered sufficient to 

withstand summary judgment. But there is at least one key difference: in tobacco 

cases, “the medical community generally recognizes the toxicity of the drug or 

chemical at issue.” McClain, 401 F.3d at 1239 (stating that “cigarette smoke . . . 

causes cancer”). This case, by contrast, is one “in which the medical community 

does not generally recognize the agent as both toxic and causing the injury plaintiff 

alleges.” Id. As a result, McCasland needed to offer more by way of proof of 

causation. See id.

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Finally, we are unpersuaded by McCasland’s claim that the district court 

violated his right to trial by jury. “It is beyond question that a district court may grant 

summary judgment where the material facts concerning a claim cannot reasonably be 

disputed.” Garvie v. City of Ft. Walton Beach, Fla., 366 F.3d 1186, 1190 (11th Cir. 

2004). And even though granting summary judgment “prevents the parties from 

having a jury rule upon those facts, there is no need to go forward with a jury trial 

when the pertinent facts are obvious and indisputable from the record; the only 

remaining truly debatable matters are legal questions that a court is competent to 

address.” Id. Thus, the grant of summary judgment—based on a determination that 

there are no genuine issues of fact for a jury to resolve—does not violate a plaintiff’s 

Seventh Amendment right to a jury trial. See id. Because we agree with the district 

court that there are no genuine issues of material fact, McCasland’s right to a jury 

trial was not violated. 

For these reasons, the district court did not err in granting summary judgment 

to Pro Guard. Accordingly, we affirm.

AFFIRMED.

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