OSHA investigators are back today at Arens Controls in Arlington Heights to try to determine what caused the explosion Tuesday that killed one employee and injured 12 other people, including three police officers and two firefighters.
Neil Nicholson, 55, of Itasca, suffered serious injuries in the explosion and was pronounced dead at the scene, according to police. His family declined today to comment.
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None of the other injuries were life-threatening, Arlington Heights Fire Chief Glenn Ericksen said.
The blast happened around 8:30 a.m. in the company's electronics testing area inside the two-story building at 3602 N. Kennicott Ave., just north of Dundee Road and east of Route 53.
The Occupational Safety and Health Administration is the only agency still investigating, Arlington Heights Police Captain Kenneth Galinski said today. The police department turned all the evidence it had gathered over to OSHA, he said. Other agencies, including the Illinois State Fire Marshal and the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives are no longer involved.
"There was nothing criminal, so we turned it over to OSHA," Galinski said.
"There's a lot of damage inside, so it's hard to tell right now if it was the chemical itself or the machine," Galinski said Tuesday. "There's a lot of destruction and devastation in there from the equipment that exploded."
OSHA spokesman Scott Allen said agency investigators will be interviewing employees and witnesses, and their investigation could take up to six months.
"We'll try to figure out if there are any OSHA standards that may have been violated and try to figure out what caused this so we can help avoid having something like this happening again," Allen said.
One thing investigators are looking at is whether potassium hydroxide -- a potentially explosive and toxic chemical -- was a factor in the explosion.
"It was a very violent explosion. There's twisted metal, buckled fencing, things like that," Ericksen said. "The roof kind of buckled up where the explosion occurred."
The explosion also sparked a small fire, which was quickly extinguished, and released a diluted form of potassium hydroxide into the air, Ericksen said.
The chemical is a skin and respiratory irritant, and reacts with some common metals to produce potentially explosive hydrogen gas, according to the website of Northstar Chemical, a distributor of industrial chemicals.
"At this point in time, we don't know what role the chemical had in the accident, if it had any role at all," Ericksen said.
The company's CEO was quoted in a brief statement the company released Tuesday evening.
"Our heartfelt thoughts and prayers are with the Arens Control Company, LLC employees and their families in the aftermath of this morning's tragic accident at our factory in Arlington Heights," Kenneth C. Kunin said. "All our efforts will go into supporting them while simultaneously working and cooperating with public safety officials and investigators to ascertain exactly what happened and why."
Two police officers from Arlington Heights and one from Buffalo Grove were the first to arrive on the scene and didn't have protective gear to prepare them for the amount of smoke and chemicals from the explosion as they entered the building to search for victims. The officers were treated at the hospital for symptoms including coughing, chest pain and headaches.
"They're going to be fine. They were released from the hospital. They're taking a few days off, and hopefully they'll be back to work soon," Galinski said.
Northwest Community Hospital in Arlington Heights treated five Arens Controls employees for exposure to potassium hydroxide, according to a hospital spokesman. The hospital also treated two Arlington Heights firefighters for presumed inhalation-related injuries.
After the initial response, officials used fans to ventilate the building and waited several hours before going back inside due to the amount of smoke and possible chemicals in the air.
The early morning blast was a shock to both employees and neighbors who reported hearing a loud boom from the back of the business, which houses both offices and an assembly area where controls are made for heavy equipment such as trucks and planes.
Although most of the damage to the building was interior, the explosion damaged the roof and sent stones from atop the building flying, damaging 20 cars in the parking lot, officials said.
Employee Shawn Kelley, a welder who started his shift at 6 a.m., was sitting in his car eating his breakfast when he heard the explosion. Stones rained down, shattering the window of his Honda Accord LX, he said.
"It was loud. I heard the explosion from the roof and all the way down," Kelley said.
"I saw a lot of rock."
Resident Bob Lee, who lives nearby, was talking a walk when he heard the boom, which he likened to "a truck exhaust backfiring."
Then he watched as ambulances from five towns attended to people outside the building.
"There were women who were pretty shook up. They were holding on to each other," Lee said.
The 50 employees in the building at the time were evacuated, but officials said surrounding businesses in the mainly industrial area were never in any danger. Arens employees huddled in the parking lot and lawn until midmorning when they were sent home for the day.
Kunin called Tuesday's explosion "a horrible accident."
"Right now, our primary concern is with the employees and the family of the deceased," he said.
• Daily Herald staff writers Paul Biasco, Deborah Donovan and Kimberly Pohl contributed to this report.