On October 11, 1998, a 51-year-old male volunteer Fire Fighter responded to a commercial structure fire with smoke showing. The victim, responding in his personal vehicle, was one of the first fire fighters to arrive at the fire scene and was notified by plant employees that the fourth-floor fire was out but that smoke was still present. The victim, accompanied by his Fire Chief and a two-man entry team, climbed up four flights of stairs to a fourth-floor landing area. While the entry team was wearing full turnout gear and SCBA, the Chief and the victim were in street clothing and no SCBA. Upon entering the interior of the fourth floor, fire fighters encountered no active fire, light smoke, and a few remaining plant employees. The victim, along with another officer, entered the fire area soon afterward and toured the area. After a total of approximately 15 minutes on the fourth floor, the victim descended the stairs, exited the plant, and was organizing a debriefing for fire fighters when he collapsed. Prior to his collapse, the victim did not display any signs or symptoms of discomfort. Immediate assessment found him to be unresponsive, with a carotid pulse but no respirations. An oral airway was inserted and assisted respirations were initiated with a bag-valve-mask. Approximately 9 minutes later, the victimís pulse was no longer present, and an automatic external defibrillator (AED) was attached to the victimís chest. A heart rhythm consistent with ventricular fibrillation was present and a shock (electrical cardioversion) was delivered but resulted in asystole (no heart beat). Cardiopulmonary resuscitation (CPR) was administered by Emergency Medical Technicians (EMTs) for a total of 21 minutes, followed by advanced life support (ALS), which was administered by Paramedics, for 25 minutes en route to the hospital. Once in the hospitalís emergency department, the endotracheal tube was checked for proper placement and ALS was continued for 2 minutes before the victim was pronounced dead, and resuscitation measures were discontinued. The death certificate listed the immediate cause of death as "a: probably myocardial infarction" [heart attack], due to "b: coronary artery disease," due to "c: diabetes." No autopsy was performed and no carboxyhemoglobin levels were measured. The following recommendations address preventive measures that have been recommended by other agencies to reduce, among other things, the risk of on-duty heart attacks and cardiac arrests among fire fighters. These recommendations have not been evaluated by NIOSH but represent research presented in the literature, regulations passed by enforcement agencies such as the Occupational Safety and Health Administration (OSHA), consensus votes of technical committees of the National Fire Protection Association (NFPA), or products of labor/management technical committees within the fire service. This preventive strategy consists of (1) minimizing physical stress on fire fighters, (2) screening to identify and subsequently rehabilitate high-risk individuals, and (3) encouraging increased individual physical capacity (fitness). Steps that could be taken to accomplish these ends include: 1. Fire fighters should have annual medical evaluations to determine their medical ability to perform duties without presenting a significant risk to the safety and health of themselves or others; 2. Provide fire fighters with medical evaluations to wear self-contained breathing apparatus (SCBA); 3. All personnel entering a potentially hazardous atmosphere must wear a SCBA; 4. Carboxyhemoglobin levels should be tested on symptomatic or unresponsive fire fighters exposed to smoke; 5. Perform an autopsy on all fire fighters who were fatally injured while on duty; 6. Collaborate with the affected plant to develop a fire safety program, including an employee evacuation protocol; 7. Attach automatic external defibrillator (AED) leads immediately to all unconscious victims; and, 8. Reduce risk factors for cardiovascular disease and improve cardiovascular capacity by offering a wellness/fitness program for fire fighters.