“Exposure to Perfluoroalkyl Substances in a Cohort of Women Firefighters and Office Workers in San Francisco” (2020), by Jessica Trowbridge and Colleagues

In 2020, Jessica Trowbridge and colleagues published “Exposure to Perfluoroalkyl Substances in a Cohort of Women Firefighters and Office Workers in San Francisco,” hereafter “Exposure to PFAS in Women Firefighters,” in the journal Environmental Science & Technology. The researchers, affiliated with the University of California in Berkeley, California, aimed to investigate occupational exposure to perfluoroalkyl substances, or PFAS, by comparing blood samples between female firefighters and office workers. PFAS are synthetic chemicals found in firefighting foam, textiles, and many household products. Research has shown that exposure to PFAS can increase the risk of health complications, including cancer and reproductive concerns. Trowbridge and colleagues sought to address a gap in previous studies of PFAS, which primarily focused on male firefighters. Their study documented increased PFAS exposure in female firefighters compared to office workers and highlighted potential health risks, particularly for those who are pregnant.

1. PFAS and Firefighters: Background
2. Article Roadmap
3. Impacts

PFAS and Firefighters: Background

Scientists refer to PFAS as forever chemicals because the substances resist degradation and accumulate in the environment. Researchers and government agencies have linked PFAS to harmful health effects, including effects on women’s health and pregnancy. PFAS enter the body through ingestion or absorption and accumulate in tissues like the breast and thyroid. They disrupt hormone production and ovarian function, which can reduce fertility. PFAS may pass to embryos through the placenta during pregnancy, which poses risks during early development. According to the National Health and Nutrition Examination Survey from the United States Centers for Disease Control and Prevention, or CDC, ninety-eight percent of people tested had a minimal quantity of PFAS. Previous research has shown that overexposure to PFAS has a number of negative health effects on women, including a lowered chance of getting pregnant, high cholesterol, and reduced immune function for both the pregnant woman and the fetus. Due to the nature of firefighting, PFAS become more volatile when they burn and can penetrate the protective gear of firefighters.

The authors of “Exposure to PFAS in Female Firefighters” were members of the Women Firefighters Biomonitoring Collaborative, which conducted a series of studies that examined the exposure of female firefighters to certain chemicals and how those chemicals are linked to breast cancer and hormone dysfunction. The San Francisco Firefighters Cancer Prevention Foundation, United Fire Service Women, the Newton, Massachusetts-based Silent Spring Institute, and the University of California, Berkeley, all collaborated on the article.

Prior research that suggested firefighters are exposed to high doses of PFAS daily primarily included male firefighters. The authors of “Exposure to PFAS in Female Firefighters” identified the lack of research on female firefighters’ exposure to PFAS as a gap in the literature. They specifically stated that filling that gap was important as more women were entering the profession. In 2020, researchers reported that the number of women in traditionally first-response roles, including firefighters, had grown over the previous decades to as much as thirty-two percent. The authors of “Exposure to PFAS in Female Firefighters” stated that they aimed to document whether female firefighters have higher exposure to those chemicals compared to their office worker counterparts.

Article Roadmap

Trowbridge and colleagues divide “Exposure to PFAS in Female Firefighters” into four main sections. In the first section, titled “Introduction,” the research team discusses previous research that documents the occupational risks of firefighting, including PFAS-related health concerns. The publication continues in “Methods,” with the authors explaining how they recruited the participants, how they analyzed blood samples from the participants, and how they analyzed the data. In “Results,” the authors present a series of graphs that analyze the different types of PFAS and their concentration in the blood samples. In the section titled “Discussion,” the authors conclude that the overexposure of PFAS in female firefighters is related to their job. They also analyze the different sources of exposure to PFAS.

In the “Introduction,” the authors hypothesize that female firefighters are more likely to have higher PFAS blood levels in comparison to their office worker counterparts. The authors analyzed two groups of voluntary participants: female firefighters of the San Francisco Fire Department in San Francisco and office workers from an undisclosed office. The United Fire Service Women, the San Francisco Firefighters Cancer Prevention Foundation, and the International Association of Firefighters contributed to the recruitment of the participants.

In “Methods,” the researchers report that they analyzed PFAS levels in two groups: female firefighters from the San Francisco Fire Department and office workers. The team explains that they conducted interviews to gather exposure histories and collected blood samples from the participants. Laboratory staff processed the samples into serum and analyzed them for twelve PFAS types, which the authors chose for their prevalence in occupational and environmental studies. Then, the research team evaluated variables, such as age, race, ethnicity, and, for the firefighter group, position in the fire department. However, the authors report that they encountered challenges because several firefighters declined to share detailed work histories. That obstacle limited the analysis of exposure intensity and specific incidents involving firefighting foam.

In “Results,” the authors report the presence of four dangerous PFAS with higher levels in female firefighters compared to their office worker counterparts. The findings show that the levels of two specific types of PFAS are nearly twice the average levels. One of the PFAS that the authors analyzed is a significant component of firefighting foams and paint additives. Overexposure to PFAS can lead to congenital abnormalities. It accumulates in the fetus and disrupts lipid metabolism homeostasis, which causes non-alcoholic fatty liver disease in fetuses.

In “Discussion,” the researchers identify several occupational factors that influenced PFAS exposure. Firefighters who engaged directly in fire suppression efforts recorded higher PFAS blood levels than drivers or support personnel. The authors also report that firehouses near airports had additional risks due to the frequent use of aqueous film-forming foam to combat jet fuel fires. Years spent wearing protective gear further correlated with higher PFAS blood levels. The authors argue that the findings highlight the importance of interventions to reduce exposure and improve the health of firefighters.

Impacts

As of 2025, “Exposure to PFAS in Female Firefighters” has ninety-six citations. Since its publication, researchers have conducted follow-up investigations into firefighting hazards. Subsequent studies in 2021 examined the effects of PFAS exposure on thyroid hormone secretion and genetic health in embryos. In 2021, some researchers of the group continued research in the same sector and designed a study to understand the effects of overexposure to PFAS on the genome of an embryo. In 2022, the researchers conducted another study to examine how the AFFF would affect thyroid hormone secretion in female firefighters. The research was conducted in collaboration with the San Francisco Firefighter Cancer Prevention Foundation.

The research group stopped publishing the series in 2023, when the authors decided to focus on finding solutions to protect against PFAS overexposure. They shifted their focus because extensive research already exists on PFAS, but no significant changes had occurred. Trowbridge and colleagues argue that the firefighting industry must adjust and implement solutions to protect all firefighters from PFAS overexposure.

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