UPDATED 11/01/11 3:58 p.m.

CHICAGO (CBS) — A hazardous materials scare at O’Hare International Airport on Tuesday sent crews scrambling, after a United Airlines employee was injured when a battery apparently exploded in a bag.

But, as CBS 2’s Mai Martinez reports, authorities said there was no criminal activity associated with the incident.

It was a scary scene that greeted passengers arriving at O’Hare Tuesday morning. Hazmat crews and emergency vehicles were out on the tarmac.

“As we were pulling in, we could see all the emergency vehicles out by the terminals,” said United passenger Christina Procita.

“I didn’t see anything severe or drastic; didn’t see a fire.” Passenger Ron Smith said. “All I could see is trucks, nothing else.”

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Emergency crews responded after a United Airlines employee was burned while unloading a container from a plane around 10:30 a.m. Initial reports cited a small explosion, but airport officials would not confirm that.

“There was an accidental discharge of a battery, that was (on a) connecting flight coming through Chicago,” Aviation Commissioner Rosemarie Andolino said. “That piece of equipment … erupted, there was one injury by a United employee. He’s been taken to the hospital, but they’re not life-threatening. … It was just a, I believe, a burn.”

An ambulance transported the worker with non-life-threatening injuries to Resurrection Hospital. The injured employee has since been released from the hospital.

The incident caused minor disruptions for arriving United flights, including several gate changes.

“We sat on the tarmac for about 35 minutes,” Procita said.

Baggage processing was also delayed.

“I haven’t seen any of the flight tags come out for our flight at all. I dont’ think anyone’s gotten their bags,” Procita said.

Airport officials said that was because the incident happened on the baggage conveyor belt, but operations were back to normal by 1 p.m.

“There was nothing criminal in nature here. It is an accident. The public is not is harm’s way,” Andolino said.

A United spokesperson said the incident caused some minor flight delays, but couldn’t say exactly how many flights were affected.

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