A 55-year-old man from Itasca, IL, was killed May 22 in Arlington Heights and 17 others were injured when an explosion in a factory tore through a testing area. The blast also sent potassium hydroxide fumes into the air and launched rocks from the roof to the parking lot, where 20 cars were damaged.

Initial examinations by the Illinois State Fire Marshal’s office and the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives have called the blast “probably accidental.” The U.S. Occupational Safety and Health Administration (OSHA) has now taken over the investigation.

The worker who died in the Arlington Heights explosion was 10 feet away from a Thermotron test chamber he was operating at Arens Controls, a manufacturer of electronic devices for commercial and hybrid vehicles. The test that led to the fatality consisted of exposing parts to high and low temperatures.

Investigators believe a metal cage around the machinery helped contain shards and debris and prevent other fatalities. Those injured were examined at area hospitals for chemical exposure, concussions, smoke inhalation, chest pains and hearing loss, and released after treatment.

While potassium hydroxide can be corrosive or explosive under certain conditions, preliminary studies do not point to the chemical as the explosion’s cause. It was determined that the fumes posed no risk to nearby residents.

At the same time, in an article that appeared in The Daily Herald on May 23, Kristen Leckrone, an associate professor of chemistry at Roosevelt University, said the chemical “demands caution when working with it, even in laboratory conditions. People expecting to encounter the substance, potassium hydroxide, normally wear gloves, goggles, and sometimes even a respirator if there’s a possibility of it being released into the air.”

In a 2010 study of injury-related occupational fatalities in various industry sectors in Illinois, manufacturing was third, accounting for 10.8 percent of the 203 total recorded in 2010. (Transportation and warehousing were number one at 16.7 percent, and construction second at 12.8 percent.)