NIOSH Finds Elevated PFAS Concentrations in Blood of Maui Firefighters
NIOSH has assessed exposures to per- and polyfluoroalkyl substances among firefighters and other Maui County employees involved in the first five days of response to the 2023 Maui wildfires. Higher concentrations of PFAS were found in blood samples submitted by firefighters compared to other first responders, according to a Morbidity and Mortality Weekly Report published by CDC on Feb. 6.
Thousands of structures were destroyed and 102 people lost their lives in the wildfires that burned throughout August 2023 in Maui, Hawaii, the MMWR states. Maui County firefighters, police officers, public works employees, and ocean safety officers—members of the island-wide public lifeguard service—participated in fire suppression, structure protection, water rescue, evacuation, and urban search and rescue. In September 2023, NIOSH medical and exposure assessment staff and a CDC logistician traveled to Maui County at the request of local officials. The NIOSH and CDC team analyzed blood samples provided by 258 Maui County employees who participated in the initial wildfire response, including 178 firefighters.
Agency staff evaluated the summed concentrations of seven PFAS, as well as concentrations of perfluorohexane sulfonic acid, or PFHxS, in first responders’ blood serum. PFHxS is one of the most biologically persistent PFAS, the report states. Among firefighters, the median summed concentration of seven PFAS was 7.0 μg/L, whereas the median summed concentration for other occupations ranged from 5.7 to 6.9 μg/L. The highest concentrations of PFHxS were also detected among firefighters, with a median concentration of 1.2 μg/L.
One firefighter was found with a PFHxS serum concentration of 9.3 μg/L, about twice the 95th percentile concentration for PFHxS in data collected by CDC’s National Health and Nutrition Examination Survey during the 2017 and 2018 survey years. This firefighter also had a summed PFAS concentration above 20 μg/L, the clinical threshold set by the National Academies of Sciences, Engineering, and Medicine. As NASEM recommends that clinicians screen individuals with PFAS concentrations above this threshold for cancer and other health effects, this firefighter was advised to consult a healthcare provider.
In general, firefighters with job tenures of 30 years or longer had higher summed PFAS concentrations, the MMWR states. A few outliers occurred among firefighters who had been on the job for less than five years. Firefighters were invited to enroll in the National Firefighter Registry for Cancer, which was created through the Firefighter Cancer Registry Act of 2018, for long-term surveillance.
According to CDC’s report, firefighters may be exposed to PFAS in fire effluents and dust, contaminated gear or equipment, protective clothing, and firefighting foams. Other studies have found that firefighters have higher blood serum concentrations of PFHxS and other PFAS compared to the general and other working populations. PFAS exposure is associated with cancer, changes in cholesterol levels, and other adverse outcomes.
The report notes that although firefighters in this assessment had higher concentrations of some PFAS in their blood than employees in other occupations, most firefighters’ PFAS concentrations were below relevant clinical thresholds. Although inconsistent use of personal protective equipment may increase firefighters’ risk of exposure to PFAS, it is unclear how much the 2023 Maui wildfires contributed to PFAS concentrations in firefighters’ blood. Samples were collected about one month after the initial response and no baseline samples were provided. However, the findings of this MMWR are “useful to advancing understanding of health implications and guiding public health decision-making for ongoing and future fires,” the report states.
More information is available in CDC’s MMWR.
Related: A NIOSH health hazard evaluation report published in July 2024 evaluated Maui first responders’ exposures to PFAS, heavy metals, and other hazardous chemicals. Previous Synergist articles discuss efforts to understand and reduce cancer in firefighters and how to protect wildland firefighters in extreme environments.
