TOMAHAWK, WI (WSAU) -  An injured worker from the Packaging Corporation of America mill in Tomahawk is still in critical condition. 53-year-old Mike Slesicki was flown to the University of Wisconsin Hospital’s Burn Center late Tuesday morning.

PCA spokesman Dave Blank says Slesicki is an experienced worker who’s been with them nine years. He was reigniting a coal and bark fired boiler that was down for maintenance. Blank says Slesicki was using standard operating procedures when the boiler flared back at him.

Federal officials are also investigating the incident. Occupational Safety and Health Administration spokesman Scott Allen says the investigation could take up to six months.

The PCA Tomahawk plant has a history of injuries and death. Two Michigan contractors suffered fatal burns at the plant last July. An explosion from a a storage tank killed three people in 2008.

Packaging Corporation of America produces containerboard and corrugated packaging materials.