A workshop filled with explosives caught fire near Rochester, setting off multiple blasts and sending a man to the hospital suffering from burns and smoke inhalation, authorities said.

The blaze engulfed the structure about 8 p.m. Saturday on property in the 3600 block of Ranch Court SE., in Marion Township, just southeast of Rochester, according to a spokesman for the Rochester Fire Department.

The fire was visible to motorists on Hwy. 52, and "numerous calls came into the 911 center reporting explosions at the location," said Deputy Fire Chief Steve Belau.

Six mortars used for aerial fireworks ignited, three of them after firefighters arrived, Belau said.

"This was a very dangerous situation, more so than usual for firefighters," the deputy chief said. "We never know what we'll be confronted with. It's tough to scare a firefighter, but those mortars were closed and loud."

Also in the workshop but spared from the flames were compressed gas cylinders of acetylene, oxygen and liquid propane, Belau said.

One building that shared a roof line with the workshop was damaged. Two homes and other buildings on the property were not harmed. The workshop was considered a total loss.

The workshop's lone occupant, 37-year-old Jeremy Huey, was taken by ambulance to St. Marys Hospital in Rochester. The victim's condition was not immediately known, the chief said.

Shorty Caflisch, who shares a drive with the property where the fire occurred, said Huey "got too close trying to put out" the blaze with water. "He was kind of critical this morning, critical but stable," Caflisch said.