Fire officials: Minneapolis explosion was accidental

Minneapolis fire officials said Thursday the cause of an explosion which injured two people at a metal tube manufacturer was accidental. A department spokesman said a welding torch ignited an aluminum dust and water mixture Wednesday at Metal-Matic, not far from the Stone Arch Bridge.

A similar-sounding incident happened there before.

According to the Minnesota Occupational Safety and Health Administration, or OSHA, a 2005 explosion injured one employee. A summary of the company's OSHA compliance history includes the following description, "Employee started up a tube mill, which produces aluminum dust as part of the process and a fire started in the almunizing box. The mill was shut down, the fire put out and when the system was restarted, the mill exploded, resulting in burns to an employee's face."

OSHA fined the company $12,400 after the incident. Part of the fine was for "not installing and maintaining the arc spray system and associated dust collection system on the tube mills to control the dust and prevent an explosion."

Minneapolis fire officials say Wednesday's explosion "took place when a pipe welding torch ignited an aluminum dust and water mixture."

OSHA spokesman James Honerman did not draw any comparison between this week's explosion and the one in 2005. Right now, Minnesota OSHA is conducting an investigation into what happened in the most recent incident.

"We're going to inspect the work areas for safety and health hazards and try to determine what caused or contributed to the accident. And then review whether existing OSHA standards were violated."

OSHA inspectors have visited the plant seven times over a 13-year period and issued citations in all but one instance. One inspection involved a serious injury in 2015.

An official with Metal-Matic has not returned a call for comment.