PITTSBURGH A bomb squad responded to a report of heavy smoke at Pittsburgh International Airport on Thursday and found a singed bag concealed in a men's bathroom.
An airport concourse nearest the bathroom was shut down at 7:30 a.m. (1230 GMT) after smoke was seen coming from the restroom, according to JoAnn Jenny, a spokeswoman for the Allegheny County Airport Authority.
The bomb squad was called to the scene and found a charred bag, which contained a sleeping mat, inside a plumbing access panel, Jenny said.
She said investigators determined the smoke was caused by a lit cigarette that was flicked behind the panel, setting fire to paper towels and other trash trapped there and charring the bag.
Fire marshals were investigating the incident.
The concourse was reopened to the public at 11 a.m. (1600 GMT). While it was closed, flights for Delta, American and United Airlines were redirected to another concourse.
(Reporting by Drew Singer; Editing by Barbara Goldberg and Stacey Joyce)