An employee was carrying a chainsaw from his truck to his work location. The gas cap was not properly secured at the time. While he was walking, some of the gas spilled out onto his right pant leg. He set the saw down and was walking back to his truck to get more tools while smoking a cigar. As he was attempting to discard his cigar it struck his outer layer of clothing, igniting the fumes from his fuel-soaked pant leg. He suffered third degree burns to his right forearm, abdomen, and chest area.