Tractor traveling from Wisconsin to Illinois leaked ammonia
The 59-year-old man was traveling in a John Deere tractor that was towing two 1,000-gallon side-by-side anhydrous ammonia tanks from a farm in Pleasant Prairie early Thursday when the ammonia started leaking, Lake County Sheriff's spokesman Christopher Covelli said. The leak happened in Beach Park, about 40 miles (65 kilometers) north of downtown Chicago.
The man driving the tractor and its owner are cooperating with authorities, Covelli said. No explanation has been provided on the cause of the leak.
More than three dozen people ended up in hospitals, mainly with breathing problems. Seven of those remained in intensive care Friday, including a firefighter. The majority of the injured have been treated and released from hospitals. Eleven firefighters and three police officers were injured.
National Transportation Safety Board investigators inspected the ammonia tanks and tractor Friday. NTSB lead investigator Timothy DePaepe said the tanks and tractor would be sent to the manufacturer's facility in Illinois where parts would be taken as evidence and for further examination.
"We will also be interviewing all of the injured individuals and as many of the fire and police responders as we can," DePaepe said. "The EPA is out on site. They're testing to make sure the area is safe."
Toxic gas plumes formed and lingered for several hours after the anhydrous ammonia leaked .