Abstract: On August 14, 1990, Employees #1 and #2 were activating a Grieve industrial rotary furnace that had been out of use for a period of time. The operating temperature of the furnace is 340 degrees F. Employee #1 had glanced into the box prior to starting it up and saw nothing. Having turned the furnace on, the two employees were waiting for it to come up to temperature while standing in front of the open light metal access flaps in the furnace doors, which were open. As the employees were about to leave, an explosion occurred in the box of the furnace. Employees #1 and #2 were burned by the flaming gases. An aerosol can containing an antistick compound, which had been absentmindedly left in the furnace, caused the explosion. The aerosol can had a bursting temperature of 122 degrees F and the contents had a flash temperature of 206 degrees F open cup.