The Hazard Evaluations and Technical Assistance (HETA) Program responds to requests from employers, employees, employee representatives, other Federal agencies, and State and local agencies. Through a staff of industrial hygienists (IHs), engineers, occupational physicians, epidemiologists, other health professionals, and support personnel, the Hazard Evaluations and Technical Assistance Branch (HETAB) collaborates with appropriate personnel in other divisions of the National Institute for Occupational Safety and Health (NIOSH) to respond to approximately 450 requests for assistance each year. The typical HETA response to a request for assistance results in (l) an evaluation of whether chemical, physical, biological, or other agents are hazardous as used or found in the workplace and (2) the development of recommendations for control procedures, improved work practices, and medical programs to reduce exposure levels and prevent adverse health effects. Health Hazard Evaluation (HHE) site visits are conducted if warranted, and interim and final reports are developed and distributed to employees, unions, management, and relevant State and Federal agencies. When the HETA request is from a Federal, State, or local agency for assistance in investigating another workplace, NIOSH provides only the technical assistance (TA) requested and does not conduct a complete HHE. The results of individual evaluations may trigger wider studies of similar exposures in other settings or may stimulate recommendations for implementation or modification of health standards. Approximately 12,000 evaluations have been completed since the inception of the HETA Program in 1972. Requests received by the HETA program often reflect widespread occupational problems, such as the hazards of fire fighting. One-hundred and fifty-nine fire fighter-related HHEs were requested from 1990 to 2001; the majority of the requests came from city and county fire departments, the International Association of Fire Fighters (IAFF), and the U.S. National Park Service (NPS). This document contains a summary of 30 HHEs related to fire fighting that involved a site visit between 1990 and 2001, categorized by the focus. Of the 30 HHEs, 7 were related to respiratory health effects and safety and health programs and procedures, 8 to diesel exhaust, 5 to forest fire fighting, 6 to chemical fires, 2 to communicable diseases, 1 to arsenic poisoning, and 1 to inspecting fire scenes at buildings with chromated copper arsenic (CCA)-treated lumber. Unlike HHEs in the previous decade (1980-1989), not many fire-fighting HHEs were related to chemical fires (6 compared with 30), and none were related to noise exposure (0 compared with 9). In most cases, multiple exposures were investigated at the work site; generic as well as site-specific recommendations were always provided. The purpose of this document is to amass the past decade of fire fighting HHEs in a concise format for easy reference and examination by NIOSH researchers, customers, and partners. Any individual reports or letters of interest can easily be requested. The scope and presentation of the individual HHEs vary based on the requesters' needs and the project officers' professional judgment.