NORTHERN STATES POWER - SHERCO 1 AND 2

BURN - COAL DUST EXPLOSION CAUSED BY DEFECTIVE LIGHT

A lead worker and four other employees were assigned the task of changing dust f ilter bags on a coal dust collector at an electric power generation plant. Using their employer's energy control procedures, they isolated the system and set up the job. The lead worker was then called to the supervisors' office. The other four employees continued the job. Two of them were working at the floor level. T he other two were at an upper level on a work platform. The area was classified as a Class 2, Division 1 hazardous location throughout the entire room. The empl oyees were using two portable 500-watt quartz lights--one on the work platform a nd one at floor level. The light at floor level had a broken lens. While this li ght was on, one of the two employees on the floor level turned to adjust his dus t mask. When he turned back, he noticed coal dust falling on the light and reali zed that that was an explosion hazard. He reached for the light, and it exploded , burning him and his coworker on the arms, face, and neck. The two employees we re hospitalized for their injuries.