The Grinnell hospital has been fined $4,000 in the death of a worker last month. A rooftop helicopter landing pad had been covered with snow after a storm in the middle of January. Forty-two-year-old Randy Criswell was clearing it away with a garden tractor when it rolled backward and went over the edge of the roof, falling past a safety net to the ground below.

Criswell died of head injuries and on Friday the Occupational Safety and Health Administration notified the hospital that the John Deere tractor’s operating manual says it shouldn’t be used around dropoffs. The hospital’s changed its operations since then, and now will have at least two workers together clearing snow up there, none using motorized riding equipment.

Audio: Radio Iowa’s Stella Shaffer report. :39 MP3