AFFF Firefighting Foam Lawsuit

The Science of PFAS Contamination

Per- and polyfluoroalkyl substances comprise a family of more than 14,000 synthetic chemicals characterized by chains of carbon atoms bonded to fluorine atoms. The carbon-fluorine bond is the strongest single bond in organic chemistry, with a bond dissociation energy of approximately 536 kJ/mol. This extraordinary stability is what makes PFAS useful as surfactants, water repellents, and fire suppressants — and what makes them virtually indestructible once released into the environment. PFAS do not hydrolyze, photolyze, or biodegrade under normal environmental conditions, earning them the designation "forever chemicals."

AFFF formulations typically contained PFOS (perfluorooctane sulfonic acid) as the primary active ingredient in 3M products, or PFOA (perfluorooctanoic acid) in formulations using fluorotelomer-based chemistry. When AFFF is deployed — whether in an actual fire emergency or during routine training exercises — PFAS compounds are released onto the ground surface. From there, they migrate through soil into groundwater aquifers, where they can travel significant distances from the point of release. PFAS are water-soluble and highly mobile in soil, making them particularly difficult to contain once released.

The bioaccumulation of PFAS in human tissue is a critical factor in the litigation. PFOA has a half-life in the human body of approximately 3.5 years, while PFOS has a half-life of approximately 5 years. This means that chronic low-level exposure through drinking water results in steadily increasing body burdens over time. Blood serum levels of PFAS among exposed populations can be orders of magnitude higher than background levels in the general population. 3M discovered in the 1970s that PFAS levels in the blood of its production workers were approximately 1,000 times higher than in the general population — a finding the company concealed for decades.

The mechanisms by which PFAS cause cancer and disease are increasingly well understood. PFAS are known endocrine disruptors that interfere with thyroid hormone synthesis and metabolism, explaining the established link to thyroid disease. They activate peroxisome proliferator-activated receptor alpha (PPARα), promoting hepatocellular proliferation and contributing to liver damage and potentially hepatocellular carcinoma. PFAS suppress immune function by interfering with antibody production and T-cell activation, and emerging research suggests they may promote carcinogenesis through epigenetic modifications, oxidative stress, and disruption of cell signaling pathways.

What the Manufacturers Knew

3M Company, the primary manufacturer of PFOS-based AFFF, had extensive internal knowledge of the toxicity of its products dating to the 1970s. Internal 3M studies found that PFAS accumulated in the blood of production workers at concentrations approximately 1,000 times higher than in the general population. Company toxicologists concluded that PFOA and PFOS "should be regarded as toxic" based on animal studies showing liver damage, reproductive harm, and tumor formation. Despite these findings, 3M continued to manufacture and sell AFFF without disclosing the known health risks to users or the public.

3M also took active steps to suppress independent research. The company hired Professor John Giesy of Michigan State University to conduct PFAS research that would be "company-friendly," providing him with funding and data while maintaining influence over the direction and publication of findings. This strategy was designed to control the scientific narrative and delay regulatory action. 3M did not voluntarily halt PFOA and PFOS production until 2000, after the EPA began investigating the chemicals — and even then, the company continued to sell existing AFFF inventory.

DuPont's conduct regarding PFOA was equally egregious. In 1980, two of eight pregnancies among female workers exposed to PFOA at DuPont's Washington Works facility in Parkersburg, West Virginia resulted in birth defects. DuPont concealed this finding from regulators and the public. Throughout the 1990s, DuPont's own animal studies showed that PFOA caused tumors in laboratory rats, yet the company continued to discharge PFOA into the Ohio River and release it into the air, contaminating the drinking water of tens of thousands of downstream residents.

The full scope of manufacturer knowledge was documented in a 2023 article in the Annals of Global Health titled "The Devil They Knew," authored by Brennan and colleagues. Through analysis of industry documents obtained in litigation, the researchers demonstrated that PFAS manufacturers knew of the dangers posed by their products as early as 1970 and systematically concealed this knowledge for decades. This pattern of corporate concealment — manufacturing products known to be toxic, hiding evidence of harm, and fighting regulation — is central to the punitive damages claims in the AFFF litigation.

The Future of AFFF Litigation

MDL 2873 represents one of the largest and most complex environmental mass torts in American history. The water utility settlement track has largely been resolved, with 3M ($10.3 billion), DuPont/Chemours/Corteva ($1.185 billion), Tyco Fire Products ($750 million), and BASF ($316.5 million) reaching settlements covering hundreds of water systems nationwide. The personal injury track — encompassing the 15,216+ individual claims from firefighters, military personnel, and contaminated community residents — is advancing toward bellwether trials.

The regulatory landscape continues to strengthen the litigation. The EPA's April 2024 finalization of enforceable PFAS drinking water standards — setting maximum contaminant levels of 4 parts per trillion for PFOA and PFOS — represents the first-ever federal limits on PFAS in drinking water. The simultaneous designation of PFOA and PFOS as CERCLA hazardous substances enables the EPA to compel cleanup at contaminated sites and seek cost recovery from responsible parties. These regulatory actions validate the scientific basis for the litigation and create additional legal exposure for AFFF manufacturers.

The trajectory of AFFF litigation mirrors the asbestos and tobacco litigations that transformed those industries. The combination of concealed corporate knowledge, established causation science, massive scope of exposure, and growing regulatory pressure creates conditions for industry-transforming outcomes. For individuals diagnosed with PFAS-linked conditions, the window for filing claims remains open but will not remain so indefinitely. Statutes of limitations vary by state, and the MDL is advancing toward the bellwether phase that will establish valuation precedent for the remaining claims.