Abstract: At approximately 9:00 a.m., on April 17, 2009, Employee #1 was servicing tractor discs at a jobsite location in Maxwell CA. To service a disc, he needed to remove a metal pin, which he did so with an oxygen and acetylene cutting torch. During his work, he switched from the cutting tip to the heating tip and the torch flashed back, catching the acetylene lead and his shirt sleeve on fire. He sustained burns to his arm and the right side of his ribcage. Employee #1 was transported to a medical center, where he underwent treatment and was hospitalized. From the investigation, it was found that the hose lines were new and in good condition but the torch did not have a spark arrestor (ie backflow device).