Abstract: At approximately 6:15 a.m. on September 29, 2003, Employee #1 was working as a route driver for and regular employee of Evergreen Environmental Services, Inc. Evergreen, which operated an oil treatment, storage, and disposal facility, had a service contract with Faggart Buick, of Porterville, CA, to pump out and transport waste automotive oil to their facility. Employee #1 was unscrewing the metal cap from an above ground waste oil storage tank that was not supposed to contain any flammable liquids, when he felt a slight pressure on the cap. Also, he detected an uncharacteristic smell coming from the cap as it reached the final threads. He disregarded these precautionary signs and continued to unscrew the cap. Suddenly, the cap was violently blown off the tank, along with the loosely attached secondary containment lid. The explosion threw Employee #1 back about 14 feet and caused second- and third-degree burns on his head, chest, hands, and arms. He was hospitalized. An employee of Faggart Buick was inside the maintenance shop when he heard the explosion and saw the windows blown out, but he did not see how it happened.