Firefighter Occupational Exposures Project: Enhancing Biomonitoring

Introduction
Firefighters may be exposed to toxic chemicals by inhalation, ingestion, and dermal absorption. Workplace sampling quantifies external exposure, but internal concentrations of chemicals from fires and hazardous materials incidents can be measured only by biological monitoring. Such studies among firefighters are extremely rare. Biomonitoring California (Program), the nation’s first mandated biomonitoring program, and the University of California Irvine Center for Occupational and Environmental Health conducted the Firefighter Occupational Exposures Project (FOX) to document internal chemical doses in firefighters.

Methods
We analyzed chemicals in blood and urine from 101 firefighters recruited at the time of their wellness-fitness evaluations and obtained questionnaire data and firehouse walkthrough environmental assessments. Participants received their test results in compliance with Program requirements. We present data for the first chemical categories analyzed and associations with potential sources. Statistical analyses were conducted using SAS.

Results
With a few exceptions, concentrations of selected blood metals and serum perfluorinated chemicals were within reference ranges compared to the US National Health and Nutrition Examination Survey and available occupational standards. Associations of biomonitoring results with demographic and lifestyle factors, job duties, work history, personal protective equipment use, and firehouse characteristics will be presented.

Discussion
FOX demonstrates the feasibility and challenges of biomonitoring chemicals in firefighters. Biomonitoring may be reassuring if results are within occupational or population levels; results outside reference ranges may trigger concern about potential health effects and follow-up to identify sources and reduce exposure. Abnormal levels may be difficult to determine and interpret because exposure sources are diverse, reference levels have not been established, and causality is complex. Results interpretation may also be affected by differences in sampling designs and laboratory detection limits. Potential interventions such as changes in work practices to reduce chemical exposures should be based on supplemental worksite measurements, comparisons with other relevant populations, and potential health effects.