Abstract: On January 29, 2006, Employee #1 was working on top of an asphalt storage tank to determine the amount of oxidized asphalt in the tank, when the vapors in the tank caused it to explode. The Cook County Office of the Medical examiner determined the employee died of multiple injuries due to the explosion. The tank was 20 ft in diameter and the top of the tank was about 35 ft above ground level. Three open flame kerosene heaters were being used to heat the tank and they were directed at the outside of the steel tank. The primary language spoken at the jobsite, including Employee #1, was Spanish.