Cancer among firefighters

A firefighter exits a burning building

Firefighter using a water hose on fire truck to extinguish a portion of a forest fire

A firefighter moving through a bush fire

Cancer risk in the U.S. fire service is a topic of growing concern. Firefighters regularly encounter carcinogenic materials and hazardous contaminants on the fireground.^[1][5] Several studies have documented airborne and/or dermal exposures to carcinogenic compounds during firefighting, as well as contamination on turnout gear and other equipment worn by firefighters.^{[6][7][8][9][10]}  Some of these compounds have been shown to absorb into firefighters’ bodies.^[11][12] Some firefighters also work with hazardous materials and are trained to control and clean up dangerous materials such as oil spills and chemical accidents.^[13] In addition to chemical exposures, night shift work has been classified by IARC as a probable human carcinogen.^[14]

Unlike structural firefighters, wildland firefighters typically do not wear respiratory protection, and may inhale particulate and other compounds emitted by the wildfires.^[15] A risk assessment conducted using an exposure–response analysis concluded that wildland firefighters could have an increased risk of lung cancer mortality.^[16]

Recent studies suggest that exposure on the fireground may increase risk to firefighters of certain types of cancer and other chronic diseases.^{[17][18][19][20][21][22][23][24][25][26]} In addition to epidemiological studies, several mechanistic studies using biomarkers have found evidence of DNA damage, oxidative stress, and epigenetic changes related to firefighters' exposures.^{[27][28][29][30][31][32][33]}

In 2022, IARC completed an evaluation on the carcinogenicity of the occupation of firefighting and reached a consensus classifying it as a known human carcinogen. This classification was based on sufficient evidence for increased risk of mesothelioma and bladder cancer among firefighters. Limited evidence of increasing risk among firefighters was also found for five other cancers: colon, prostate, testicular, melanoma of the skin, and non-Hodgkin lymphoma.^[34]

Data sources

While U.S. state cancer registries provide rich data for studying cancer in the U.S., they often do not provide comprehensive information on cancer patients’ work history^[35][36][37] and workplace practices, making it challenging to use this data source alone for studying cancer in firefighters. It is also important to collect information on personal and lifestyle risk factors (e.g. tobacco and alcohol use, sleep deprivation, diet, and physical activity) in the U.S. fire service to better understand how they may affect the relationship between firefighting and cancer.^[38][39][40]

Due to the lack of central and comprehensive sources of data, research on cancer rates amongst firefighters has been challenging. Although some evidence suggests the risk for specific cancer types could vary for male, female, and non-white firefighters,^{[41][42][43][44]} the strength of the evidence related to cancer in demographic subgroups is limited because many previous studies have mainly comprised white male samples of firefighters. Larger samples of female firefighters and minority groups are needed before the conclusions can be drawn about cancer risk across the nation’s diverse fire service.^[45][46] Additionally, the research on cancer for some subspecialty groups of firefighters, such as firefighter trainers, is limited.^[47]

Firefighter enrollment

All members can enroll through a web portal. NIOSH states that any information gathered through the program will only be accessible to NIOSH researchers and will be protected with multi-factor authentication and "multiple layers of encryption."^[62] Firefighters may access the web portal through the dedicated NFR website (https://www.cdc.gov/niosh/firefighters/registry.html or https://www.cdc.gov/NFR) or by directly accessing the web portal. To complete enrollment in the NFR, participants will need to set up an account, complete an informed consent document, user profile, and enrollment questionnaire.^[60][62]

The user profile will serve to collect basic information from the firefighter that could change over time and hence can be accessed and updated by the user. The enrollment questionnaire will collect information on employment/workplace characteristics, exposure, demographics, lifestyle factors, comorbidities, and other confounders. Most questions are optional. The enrollment process, including the questionnaire, is designed to take 30–45 minutes to complete if all questions are answered.^[60][62] Following enrollment, NIOSH will send NFR participants notifications for periodic voluntary follow-up questionnaires (e.g., one per year) to be filled out through the web portal.^[60][62]

Other sources of information

In addition to roster information, NIOSH plans to request fire incident records dating back to January 1, 2010, or earlier when available, from fire departments for some participants. Fire departments are required to collect some basic information about fire incidents under the National Fire Incident Reporting System (NFIRS) established by the U.S. Fire Administration. (The U.S. Fire Administration is in the process of replacing NFIRS with a new system called the National Emergency Response Information System (NERIS).) Department incident records will provide NIOSH investigators with apparatus and incident-specific information to be used as surrogates of exposure for exposure-response analyses. Specific variables of interest requested from department incident records may include: incident number, fire station, apparatus, incident type (structure fire, car fire, etc.), on scene time, off scene time, job assignments, number of fire runs, and duration at fires. NIOSH will explore the most efficient and least burdensome way of obtaining incident records from participating fire departments.^[60][62]