A truck driver was fatally struck in the head by one of the large plastic pipes he was delivering Tuesday morning to a construction equipment business in Blaine, police said.

The incident occurred shortly before 9 a.m. at Gary Carlson Equipment in the 10700 block of Mankato Street, just west of Radisson Road NE., said police Lt. Dan Pelkey.

The semitrailer truck driver, in his 20s and from Missouri, was unloading the 12-foot-long pipes from his trailer when “one came off the trailer and struck him,” Pelkey said.

The man was taken by emergency responders to Mercy Hospital in Coon Rapids with critical injuries and later died, the lieutenant said. The driver’s name has not been released.

Emergency scanner traffic indicated that the pipe hit the man in the head and left him unconscious but still breathing as he was taken from the loading area.

The man’s death is being investigated by the state’s Occupational Safety and Health Administration.

For the five years ending in 2015, workplace deaths in Minnesota involving “contact with object/equipment” averaged nearly eight per year, according to state statistics. That category includes contact with vehicles such as trucks, forklifts and front-end loaders, said agency spokesman James Honerman.

That category also accounts for the most common instances of workplace fatalities, making up 42 percent of the 92 deaths overall from 2011-15.