CEDAR FALLS, Iowa  No injuries were reported after a power generating station exploded on the outskirts of Cedar Falls Monday morning.

Two Cedar Falls Utilities workers were inside the building at 2506 W. 27th St. when the blast damaged the facility, said Fire Chief John Schilling. He said the two were examined by paramedics and released at the scene.

The cause of the explosion hasn't been determined, but Shilling said the blast leveled about half of the building.

The explosion happened about 10 a.m. and was heard across the city. Schilling said he heard the noise from City Hall downtown.

He said the accident won't affect power to the city.

Schilling said there was no debris outside the site, and windows in neighboring buildings were intact.

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Betty Zeman, a Cedar Falls Utilities spokeswoman, said the site is a backup facility and used only during days with peak power demand or during emergencies. This morning, the two workers — Steve Balthazor and Kevin DeSerano — were undertaking a required annual "urge test" on the No. 2 gas combustion turbine when the explosion occurred.

They were at a control panel when the blast occurred in another part of the building, she said. She said they were wearing hearing protection because of normal noise in the facility.

She said there were no issues with gas leaks.

I'm the city editor at the Quad-City Times. You can reach me at dbowerman@qctimes.com or 563-383-2450.