Faust: After 26 Years of Fires, an Employer Must Prove No Link, Not Just No Studies

A firefighter retires, or is about to, and learns he has cancer. He knows what he breathed for decades. He does not have a study proving that those fires caused this cancer in him, and no one could easily produce one. California law does not make him find it. Once a covered firefighter or peace officer shows a few basic facts, the law presumes the cancer came from the job, and the employer has to disprove the connection.

The question in Walter Faust’s case was what disproving it takes. The Workers’ Compensation Appeals Board answered in Faust v. City of San Diego, 68 Cal.Comp.Cases 1822, No. SDO 244774 (WCAB en banc Dec. 11, 2003), a decision that binds Board panels and every workers’ compensation judge. The employer must identify where the cancer started and must prove, with medical evidence, that there is no reasonable link between the worker’s exposure and the cancer. Evidence that no study has shown a link does not do it. The Board set aside the judge’s ruling against Faust and sent the case back to apply that test. It did not decide whether his cancer was industrial.

Twenty-six years and a diagnosis

Faust joined the San Diego fire department in February 1972. In April 1998 he was diagnosed with prostate cancer. He stopped working, had surgery in May and retired that July. The City denied his claim in September 1998.

He had a long list of fires. He told one evaluator about a total burnout at San Diego Plating in the 1970s, a tuna boat with burning chemicals, a soap factory, creosote-coated poles, and garage fires with paint lockers and pesticides. He did not regularly wear breathing apparatus before 1983 or 1984. A coworker testified about burnt rubber, resins, paints and batteries. A plating company employee testified that cadmium was used in certain plating and that the company usually sent that work out. Faust believed he had been exposed to cadmium, but he was not certain.

Two doctors and two readings of the literature

Each side had a qualified medical evaluator. Dr. Prakash Jay, for Faust, cited studies finding increased rates of prostate cancer in firefighters. He identified cadmium as “the only well documented chemical carcinogen that is implicated in the causation of prostate cancer,” concluded Faust had been exposed to it, and found the cancer industrial.

Dr. Frederick Fung, for the City, ran his own search. He wrote that “there are no documents in the world medical and scientific literature that associates prostate cancer and firefighters.” He tied the disease to hormones, and later challenged each study Dr. Jay had cited. He concluded: “There is no association between exposure by firefighters and prostate cancer.”

The trial judge recognized the presumption but concluded Dr. Fung’s opinion had rebutted it, relying on the general rule that one doctor’s considered opinion can be enough. The cancer claim failed, and Faust asked the Board to reconsider.

In 1999 the burden moved

The older version of Labor Code section 3212.1 made the firefighter show two things before the presumption applied: exposure to a known carcinogen, and that the carcinogen was “reasonably linked to the disabling cancer.” A reasonable link meant a logical connection, something more than coincidence.

The Legislature changed that in 1999. It took the reasonable-link requirement out of the firefighter’s case and put it into the rebuttal. The presumption can now be controverted by evidence that the primary site of the cancer has been established and that the carcinogen “is not reasonably linked to the disabling cancer.” Unless it is, the Board “is bound to find in accordance with the presumption.” The worker, the Board concluded, “is no longer required to establish a reasonable link between the exposure and the cancer.”

Faust had filed in 1998, but the amendments reached claims filed or pending on or after January 1, 1997, including denied claims. The Board decided his case under the amended statute.

What the firefighter must show

The worker still starts with a burden, and Faust set it out in three parts. The statute also covers certain peace officers, and its current list of covered workers is longer than the one Faust addressed, though the opinion speaks mostly of firefighters.

• Covered employment. Stipulation, testimony or documents can show the job and the dates.
• Exposure to an identified known carcinogen. The substance must be one listed by the International Agency for Research on Cancer or defined by the director of the Department of Industrial Relations, usually shown with documents. Actual exposure can be shown by the worker’s testimony or other credible evidence. “[A] minimal exposure is enough to satisfy the applicant’s burden.” The worker need not show the exposure was the proximate cause.
• Cancer that developed or manifested in the statutory period. That takes medical evidence with a date. Manifestation includes symptoms related to the disease, even if no one has yet called them cancer, so the date can be significantly earlier than the diagnosis.

Timing can be decisive for a retiree. The presumption reaches past the last day worked, three months for each full year of service. The version in Faust capped that at 60 months. The current statute, last amended effective January 1, 2026, caps it at 120 months.

What the employer must then prove

Once those facts are in, the burden shifts. The employer must establish both of two elements. Competent medical evidence must establish the primary site of the cancer. And medical or similar expert scientific evidence must show there is no reasonable link between the exposure and the cancer.

The second element is measured by reasonable medical probability. One recognized way to meet it is latency, the time between exposure and when a cancer can appear. In a panel decision the Board cited, a worker’s colon cancer was diagnosed less than five years after his job began, and medical evidence put the latency period at ten years or more. That evidence rebutted the presumption.

If the employer fails on either element, an industrial injury must be found. If it succeeds, the claim survives, but the worker then has to prove causation by reasonable medical probability without the presumption’s help.

No studies is not no link

It is not enough, the Board held, “for the defendant to show that no evidence has established a reasonable link between the known carcinogen and the cancer.” The employer has to establish that a reasonable link does not exist. A gap in the research does not prove there is no link.

The reason follows from the 1999 change. Treating silence in the literature as proof “would improperly place the burden of showing industrial causation on the applicant.” The Legislature had removed that burden in 1999. So the absence of epidemiological studies showing more of a particular cancer in firefighters does not rebut the presumption. To rebut the presumption, the Board said, “the evidence must explicitly demonstrate that medical or scientific research has shown that there is no reasonable inference that exposure to the specific known carcinogen or carcinogens is related to or causes the development of the cancer.” Expert evidence should review the studies or other evidence that justify the opinion, with the studies attached to the report.

The employer must address each carcinogen to which the worker has demonstrated exposure, and in our reading research about firefighters in general does not do that. The Board did not apply this rule to Dr. Fung itself. But it bears on his reports. His search concerned prostate cancer in firefighters, not cadmium, and he acknowledged that an association with cadmium had been suspected, though “still controversial.” Whether challenging Dr. Jay’s studies and finding no association amounts to proof of no reasonable link was for the new decision.

Why the judge could not simply pick a doctor

Ordinarily a judge may choose among conflicting medical reports, and one doctor’s considered opinion can be substantial evidence. The Board acknowledged that, and said this was different. Where a statutory presumption applies, “a systematic analysis must be applied to the evidence presented.” The judge cannot resolve the reasonable-link question by selecting one physician over another, even if the reports look equally strong. “A mere difference of opinion between physicians is not sufficient to rebut the presumption.”

The judge here had relied on one physician over another without first working through who had shown what. The Board rescinded the findings and returned the case for a new decision using its method. It made no finding on any element. The analysis, it said, “must be completed before a decision is reached on the presumptive compensability of the claim in the present case.” In our reading, that left open whether Faust proved exposure to a listed carcinogen, and whether the City proved the primary site and the absence of a reasonable link.

How a 2025 panel applied Faust

A Board panel applied Faust in Vizcaino v. City of Sacramento, No. ADJ14177811 (WCAB Dec. 31, 2025), and reported that the Court of Appeal had endorsed its holding in City of Long Beach v. Workers’ Compensation Appeals Board (Garcia), 126 Cal.App.4th 298 (2005). The passage the panel quoted also limits what an employer must prove. An employer shows no reasonable link if it shows no connection exists or that any possible connection is so unlikely as to be absurd or illogical. It need not prove “the absence of any possible link,” and a link “that is merely remote, hypothetical, statistically improbable, or the like, is not a reasonable link.” It must show that no such connection “can be logically inferred.” In our reading, both statements now frame the employer’s burden: Faust’s demand for explicit research-based proof, and that narrower description of what counts as a reasonable link.

The same court kept the central point. If an employer could win merely by showing the absence of studies, “the practical effect would be to shift the burden of proof back to the employee, in derogation of the 1999 amendments to the statute.” In Vizcaino itself, the qualified medical evaluator, whose reports were joint exhibits, relied on a lack of medical literature linking diesel exhaust to throat cancer, and the panel held that could not rebut the presumption. We cover it in our analysis of that firefighter’s throat cancer claim.

What to gather

These steps are our practical reading of Faust, for a firefighter or peace officer making a cancer claim.

• Name the carcinogen. Identify specific substances and get the listing that shows each is a known carcinogen. General smoke exposure is a start. The presumption requires an identified carcinogen.
• Write down the fires. Faust described specific fires, what burned and roughly when, and gave the evaluator a list of other fires. Coworkers can back it up. Testimony can show actual exposure, and a minimal exposure is enough. But the proof has to connect the fire to the named carcinogen, sometimes through an expert. Faust himself was not certain about cadmium, and the Board did not decide the point.
• Find the earliest symptoms. The medical record should show when symptoms began, not just when cancer was diagnosed. That date can decide whether the presumption applies after retirement.
• Read the employer’s report for what it actually says. Does it find there is no link, with reasons and studies attached? Does it explain why any link is remote or statistically improbable, or why the timing falls outside the cancer’s latency period? Or does it only say none has been shown?
• Press for the full analysis. If the doctors disagree, the judge still has to take the worker’s three showings first, then the employer’s two elements.

For representation in a firefighter or peace officer cancer claim, see our California workers’ compensation practice.