GREENVILLE, Mich. (WOOD) — Fire investigators have determined the cause of an explosion at Dicastal manufacturing plant in Greenville last week.

The Greenville Department of Public Safety said the explosion and subsequent fire was caused by sparks from a tool. An employee was using a hand grinder on a maintenance project in the foundry area, where metals are melted. Some sparks accidentally ignited aluminum dust near the project and exploded, police said.

The explosion could be heard from miles around and caused a fire in the northeast corner of the building. Firefighters from three different departments were able to put it out. All employees who were working at the time managed to escape the building and one was taken to the hospital with burn injuries.

Dicastal North America has a history of fires and OSHA violations at the site. The Greenville Daily News reports this was the fourth fire call at the plant this year. It had a dust explosion in January, a roof fire in February and smoke in the plant a week before the explosion.

The Occupational Safety and Health Administration website lists eight violations at the Dicastal plant in Greenville. After working with the regulator, they were fined nearly $27,000.

The FBI executed a search warrant at the plant in July. The agency told News 8 it had no additional information to release Monday.