A Cook County Forest Preserve spokesman says the diver is expected to recover.
It was an "equipment malfunction," according to the Cook County Forest Preserve spokesman:
The Cook County sheriff's office says a diver for the Park Ridge fire department was pulled unconscious out of Belleau Lake in Park Ridge, about 10:15 a.m., after a diver training exercise that went wrong.
Sheriff's office spokeswoman Sally Daly says the diver was revived at the scene.
Daly says the training exercise involved divers from five suburban fire departments at Belleau Lake, which is part of the county forest preserve.
The injured diver was taken to Lutheran General Hospital.
A Forest Preserve spokesman says the diver's injuries are not believed to be life threatening.
Daly says the five fire departments taking part in the training dive were Park Ridge, Wilmette, Deerfield, North Maine Township, and Northbrook.
