A blanket of smoke around Wellstar Kennestone Hospital in Marietta on Thursday morning was the result of a fire in a parking deck that caused “major structural damage” despite being quickly brought under control, officials said.

The hospital’s blue parking deck, located at the corner of Tower Road and Church Street, became shrouded in gray smoke due to a fire that began just before 10:15 a.m., Marietta fire Capt. Steve Dau said in a statement. Crews contained the flames about 20 minutes later, but the column of smoke began raising eyebrows and eliciting questions on social media.

Six cars were damaged in the incident, Dau said, and the parking deck sustained serious damage and has been closed. Dau did not say when the structure might reopen. One person was treated on-site by hospital staff, but no other injuries were reported, Dau said.

Tower Road and Kennestone Hospital Boulevard were closed immediately after the fire, but police said Tower Road reopened about 12:15 p.m. The main entrance to the hospital was also blocked for hours.

The cause of the fire remains under investigation, Dau said.

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