AUBURN, Maine (NEWS CENTER) -- Firefighters and workers at an airport business in Auburn had a huge mess on their hands Monday morning, after a fire suppression system went off, and filled the business with foam.

Auburn-Lewiston Airport manager Rick Lamman has told NEWS CENTER it was an accident, caused when a contractor was performing a regular six-month check of the system, and accidentally triggered the foam discharge. Lawman said the system worked , as far as making foam is concerned., but the contractor wasn't able to shut it off.

"It's enough to fill the building 20 feet deep," the manager said.

About 100 people work in the Hangar for Lufthansa Technik, a subsidiary of the German airline. Their work is focused on restoring an old Lockheed Constellation airplane, reportedly bought new by the airline many years ago.

The airport manager said the foam filled the Hangar quickly and workers had to run out through it. Some had their feet and hands washed down by firefighters when they arrived. Lamman said the foam is water soluble and posed no serious health risk.

Firefighters said four workers were stranded on a second level of the building, and had to wait until the doors could open and the foam pour out of the building so they could leave. There were no serious injuries were reported.

The foam had dispersed and evaporated outdoors by about 12:30 p.m. Airport manager Lamman said there was considerable cleanup needed inside the Hangar.

"All the electronics, all the paper, all the tools will have to be washed down wiped down. And the airplane being restored in there, we aren't sure at this point what will have to be done to that yet," he said.

Lamman said the airport also has work to do to recertify the building's electrical system after it was inundated by foam.All that will all take time, he said, and cost money.

"Somebody will have to pay," said the manager.

Lufthansa managers and workers declined to comment.