A carbon monoxide leak at sent 10 people to a hospital Monday from an office building in the Falls Church area, Fairfax County fire officials said.

Hazmat units responded to the 6200 block of Leesburg Pike, near Seven Corners, and evaluated 30 people for possible symptoms of carbon monoxide poisoning about 5 p.m., said Renee Stilwell , a fire department spokeswoman.

Authorities took 10 people to the hospital for further evaluation, Stilwell said.

The cause of the leak was not immediately released.

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