Update, 12:20 p.m.:
Authorities said that the accident blocking Georgetown Pike in McLean involved an overturned tractor-trailer that was carrying sewage.
The driver sustained injuries that were not life-threatening in the accident, which happened near a construction site at Georgetown Pike and Langley Ridge Road. There were no other injuries, but some sewage spilled from the truck onto the roadway, officials said.
Georgetown Pike is expected to be closed in both directions between Spring Hill Road and Swinks Mill Road for most of Monday as crews work to clean up.
A stretch of Georgetown Pike in McLean will be closed for an extended period on Monday following a construction accident near Langley Ridge Road, not far from the Capital Beltway authorities said.
The section of the roadway between Spring Hill Road and Swinks Mill Road is expected to be closed all day in both directions, police said. Old Dominion Drive can be used as an alternate route.
No details about the accident and possible injuries were immediately available.