Abstract: On April 11, 2024, an employee working as a fire fighter for a city fire department had been participating in fire fighter training from approximately from 7:30 a.m. to 4:00 p.m. The employee spent the majority of the day performing firefighting search drills while wearing full structural firefighting turnout gear with an SCBA. The employee had participated in a morning session and an afternoon session of the drills. The drills consisted of the employee maneuvering through a single-family training house and a training motel filled with theatrical smoke while searching for mannequin props and real-life "victims". The employee would then carry or drag the "victims" out of the structure to safety. The employee performed between 3 to 5 drills at each training facility with each drill lasting approximately 10 to 15 minutes. The duration of the drill varied depending on the scenario. The employee took breaks in between drills to rest and swap SCBA cylinders and allow other employees to perform the drill. The employee performed drills at the motel in the morning and finished up the afternoon at the single-family house. The employee trained for approximately 2.5 to 3 hours at each facility. The employee also participated in a physical training warmup just prior to the start of the training day which consisted of a 3-mile run. At 4:00 p.m. on April 11, 2024, the employee ended his day and went home. At 7:30 a.m. on April 12, 2024, a family member found the employee unresponsive in his bed and contacted emergency services who notified the employer. The employee had died from cardiac arrest. As of June 11, 2024, the county coroner's autopsy report and results were not completed.