Abstract: On July 13, 1997, Employee #1 suffered second-degree burns on his hands and head when an explosion took place as he lit the pilot light on a propane water heater in the basement of a hotel. On July 15, 1997, after an investigation that did not include air testing, Employee #2 entered the basement to get information on the water heater. He did not have an intrinsically safe flashlight, and chose to use a lighter for illumination. This set off another explosion, and Employee #2 suffered second-degree burns on his hands, arms, and head. It was later determined that propane gas had been leaking from a tank buried beneath the floor. Because the propane had migrated through the soil, its odorant had faded. When the gas subsequently pooled in the basement, it had no detectable odor.