An internal investigation has shown that hydrogen gas, which had not been fully purged from the generator during unit maintenance at the coal-fired L.V. Sutton Steam Electric Plant in New Hanover County, N.C., ignited and caused an explosion that killed one worker on March 15, Progress Energy said in a statement.

Progress Energy spokesman Mike Hughes told POWERnews that the employee, Cory Rogers, 24, was killed while one of the plant’s three coal-fired steam units was shut down for maintenance. Rogers was working on a generator. Hydrogen gas, which is used as a coolant in the generator, was being purged using a process that includes the insertion of carbon dioxide.

“The investigation revealed that the hydrogen gas was not fully purged from the generator, and was ignited by a fan or work light that Rogers was using as part of performing maintenance,” Hughes said.

The company said that Progress is committed to ensuring that it fully understands what happened and implement lessons learned to further minimize hazards. Progress Energy is reviewing its procedures and will revise them at the Sutton plant and other company facilities as the assessment warrants, Hughes said.

The North Carolina Department of Labor is conducting an independent investigation. A spokesperson from the state body told POWERnews that if it finds violations of the Occupational Safety and Health Act, it can issue citations to the company. Most fatality investigations are completed within three to four months.

Sources: POWERnews, Progress Energy, N.C. Department of Labor