ALLENTOWN, Pa. (KYW/CNN) - A house explosion caused several homes to catch fire.
Fire crews in Allentown responded to 911 calls about the blast early Sunday.
The house and a neighboring home were engulfed by fire, but the flames were quickly spread to nearby homes on the block.
Officials said 10 homes were impacted, all of them occupied.
Twenty-one people were evacuated. One person remains unaccounted for.
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One firefighter suffered a shoulder injury while working to contain the blaze.
The explosion is under investigation, but firefighters reported a heavy smell of gas.
The fire chief said it was hard to reach the area.
“The location of it, being that really tight streets in there. Getting some of the trucks in there was a challenge,” Allentown Fire Chief Jim Wehr said.