Three men collapsed while cleaning out a large tank from a truck Tuesday afternoon and one of the men later died. It happened at a truck wash facility in the central Iowa town of Sully.

Jasper County Sheriff John Halferty says it’s suspected the men were exposed to a hazardous chemical. “We were notified that there were three individuals inside of a semi tank trailer,” Sheriff Halferty says. “The business cleans trailers there and these individuals had passed out and it was believed to be caused by some type of material inside the trailer.”

The man who died was a work release inmate at the Newton Correctional Center. One of the other men was an inmate as well. The third man worked for the truck wash. Paramedics pulled the three men out of the tank. The two survivors are being treated at area hospitals.

Halferty says the Sully Fire Department is conducting the investigation into the incident. “It would be similar to if there was a house fire or something,” Halferty says. “It’s mainly a fire department investigation. I’m sure there may be some other state agencies that may need to investigate as well.”

He says two other work release center inmates were working at the truck wash at the time of the incident and neither of them was injured. “The truck wash does employ inmates and has for several years,” Halferty says. “It works out really well for, obviously, both sides.”

Reporting by Randy Van, KCOB, Newton