Abstract: At 4:30 p.m. on July 31, 1990, Employee #1, a fire captain, responded with his engine crew to a fire at a residential structure. They provided water to a crew already on the scene, then checked nearby structures for flying embers. The air temperature was approximately 105 degrees F. Employee #1 felt overheated and instructed his crew to shed their turn-out gear. While on a garage roof, he began to feel nauseated and weak. After returning to the station, he suffered severe shortness of breath. He was hospitalized 3 days for extensive tests, but no definitive diagnosis was made. No code violations were noted.