Thousands of evacuated residents returned home after a major chemical fire at Advanced Magnesium Alloys Corp., Anderson, Ind., lost its intensity and an unlikely culprit was revealed.
Fire officials said water from the magnesium recycling plant's sprinkler system on Friday turned a small fire into a roaring one that burned in spectacular fashion overnight.
The metal caught fire Jan. 14th, in a scrap bin at the Advanced Magnesium Alloys Corp. plant.
Workers at the plant immediately tried to put it out with dry material because water causes burning magnesium to flare up, said Anderson Deputy Fire Chief Mike McKinley.
"Before they could put it out, the sprinkler went off," McKinley said.
The water helped to fuel the burning magnesium, which by that evening forced the evacuation of about 5,000 residents in the vicinity because of hazardous smoke.
City officials did not know why the company kept a working sprinkler near the materials.
Connie Smith, a spokesman for Anderson Mayor Kevin Smith, said fire officials making an inspection 18 months ago told plant officials to cap the sprinklers.
The sprinkler system was installed when the building was the General Motors Delphi Engine and Energy Facility.
Capping the sprinkler would have been easier than removing it, which would have required a zoning variance, Smith said.
"It's a complicated procedure because there is nothing on the books for taking out a sprinkler system," Smith said. "Usually, you want them put in."
Three hours after the fire started, it was fueled again, this time by snow on a roof that collapsed.
The burning magnesium reached 3,000 degrees, nearly three times the temperature of a typical house fire.
Flames shot 300 feet into the air, and thick plumes of gray smoke slowly enveloped a large part of the city.
Ken Rhame, an on-site coordinator for the U.S. Environmental Protection Agency, said broken water pipes in the building caused some flare-ups.
He said officials might choose to smother the fire with sand, salt or lime.
The Environmental Protection Agency and the Indiana Department of Environmental Management were monitoring air quality and consulting with city officials.
McKinley said that before officials do anything else, they will remove 800,000 pounds of already recycled magnesium slabs from the burned building.
"They're not very flammable. I don't know if you can light them with a blowtorch," he said. "But we don't want to take any chances that they catch on fire next."