The U.S. Occupational Safety and Health Administration is investigating after a worker fell out of a moving van and died in northeast Missouri.

WGEM-TV reports that 51-year-old Richard Geiler of LaBelle died Saturday at Heartland Dairy in rural LaBelle.

Lewis County Sheriff David Parrish says Geiler was riding in a transport van on the way to a feed lot when the driver accelerated, causing Geiler to fall out of the vehicle, suffering severe head trauma. He died Monday at a hospital.

An official at Heartland Dairy said Wednesday that the company is saddened by Geiler's death, but declined comment on the OSHA investigation.

The Department of Labor says OSHA has investigated three worker deaths at the farm.