MONTGOMERY CO., Md. (WPVI) —
Authorities remain on the scene of a serious, multi-vehicle pileup outside Washington, D.C.
It happened at 5:20 a.m. Monday on I-270 South in Montgomery County, Maryland.
Officials say a tractor-trailer carrying large stones and gravel crashed, losing its load and triggering a pileup involving at least 20 vehicles.
The Montgomery Co. Fire Department said medics are evaluating more than two dozen people.
Some have been taken to area hospitals as trauma alert cases.
The crash has been declared a mass casualty incident.
I-270 South was shut down for more than two hours as police, firefighters and medics responded to the scene and crews worked to clear the wreckage.
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