An autopsy late Thursday afternoon confirms a Keystone Steel and Wire maintenance worker died of a heart attack due to heart disease and not the heat.
John Decanter of Manito collapsed Wednesday after working at 12-hour shift at the Bartonville plant.
Co-workers say the 40-year-old complained of being over-heated before heading for the shower room at the plant. The main part of the steel mill does not have air conditioning.
But an autopsy Thursday found no evidence of heat stress or heat stroke. It did, however, find that Decanter had significant blockage in the coronary arteries.
A company spokesman says Keystone takes employee conditions seriously by providing an air conditioned space for breaks, water, and Gatorade.