Abstract: At approximately 10:30 a.m. on October 22, 2002, Employee #1, a plumber, and Employee #2, a plumber's helper, were working at 5221 California Street, in Irvine soldering a vertical section of 0.75-in. copper pipe. The copper pipe was approximately 18 in. above the floor set up on a horizontal stem to a sink. Employee #1 was doing the soldering and Employee #2 was standing to the right of him approximately 10 ft away observing the procedure. Employee #1 was using a hand-held MAPP (Methyl Acetylene Propadiene) cylinder torch. During the procedure, the flame flared out. Since the flare could have been caused by blockage in the torch tip, Employee #1 struck the tip on something while shaking the bottle to try to clear the tip. Employee #1 then dropped the cylinder to the floor to the right and it ruptured below the metal cylinder/torch base interface releasing the burning MAPP gas. Employees #1 and #2 sustained first- and second-degree burns and were hospitalized for two weeks.