From the outside, the Arens Controls plant where a huge explosion Tuesday killed Neil Nicholson, 55, of Itasca looks undamaged.
But given the way a testing machine was torn apart by the blast, it's lucky more people weren't seriously hurt, officials said Wednesday.
"It was tragic to lose that one man," said Arlington Heights Fire Chief Glenn Ericksen, "but with the number of people in the building, we were very fortunate."
While 17 people were treated at local hospitals or the scene for smoke inhalation and chemical exposure, no one was hospitalized, he said. Fifty people were in the factory at 3602 N. Kennicott Ave. at the time of the explosion. The company manufactures components for vehicles.
When the blast occurred, Mr. Nicholson was checking something at a Thermotron test chamber, which is capable of exposing products to very hot and very frigid temperatures, said Capt. Kenneth Galinski of the Arlington Heights Police Department.
"The machine was in pieces, chunks of steel, totally destroyed," he said. Mr. Nicholson was thrown about 30 feet. However the area where the equipment was located was inside a cage of about 20 feet by 40 feet that stopped a lot of the flying debris, thus preventing other employees from suffering serious injury, he said.
The explosion went toward a wall, up the wall and caused the roof to bubble, he said,
"It was nasty in there; the explosion was huge," said Galinski.
Mr. Nicholson was declared dead at the scene Tuesday. An autopsy conducted Wednesday determined he died of multiple severe injuries suffered in the explosion. The death was ruled an accident, a spokesman for the Cook County medical examiner's office said.
While initial investigators included local police and fire officials, the Illinois State Fire Marshal and the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives, the Occupational Safety and Health Administration is the only one still investigating, Galinski said.
"There was nothing criminal, so we turned it over to OSHA," he said.
Ericksen said he assumed the cage, which divided off a small part of a large warehouse area, was there so that section could be locked off if needed.
"As I understand it, the part that was being tested in this test chamber may have had something to do with fuel; as its end product it releases hydrogen gas," said Ericksen. "It's something the OSHA investigators are going to look at."
OSHA will also investigate potassium hydroxide. It is Ericksen's understanding that potassium hydroxide is used in the chemical process to make the part work while it is being tested.
Ericksen said he was told that two one-gallon containers of a very dilute solution of potassium hydroxide were in the area
"I was told it is similar to a concentration of drain cleaner like you would find in the hardware store," said the fire chief.
"That's the question we all want answered: What caused this testing box to go off. We have a number of theories, but we are going to have to wait for OSHA and their engineers to get the answer," said Ericksen.
That's not likely anytime soon. No information will be released until the OSHA investigation is completed and the agency has six months to finish its report according to the law, said Scott Allen, regional director of public affairs and media relations for OSHA in Chicago.
Ken Kunin, president of Arens Controls, said Tuesday that company officials' "primary concern is with the employees and the family of the deceased" and that the company would work with investigators to find "what happened and why."
Company officials could not be reached Wednesday, but village officials speculated factory operations will not resume this week.
Members of Mr. Nicholson's family said they did not want to talk with the news media.