Abstract: On August 11, 2002, Employees #1, #2, and #3 were disassembling a mixer unit on the paper recycling process line, which was powered by both steam and electricity. They had removed the bolts on the mixer unit when the sole plate blew out and struck and killed Employee #1. Employees #2 and #3 sustained serious burns from the escaping jets of steam and were hospitalized. The sudden pressure release was apparently caused by an electric control valve on the steam line that did not fully close. This allowed steam pressure to build up in the process line between the mixer and an upstream medium consistency pump. Line pressure in the process line was approximately 150 psi, equivalent to the steam line pressure. While the electric energy sources were isolated and locked out, the steam line was not.