The Delaware-based Tri-State Bird Rescue is working to clean birds oiled by a spill in the Potomac River.
The U.S. Coast Guard says a dye test will be conducted in the Potomac River and Roaches Run Waterfowl Sanctuary near Arlington, Virginia, to find the source of oil sheens spotted on the river.
The Coast Guard announced in a news release that it will work with state and local officials to conduct a dye test Monday morning in the storm water system for the Roaches Run watershed. Cmdr. Michael Keane, the incident commander, says the non-toxic dye appears bright yellow or green.
The Coast Guard believed that the sheens spotted last week were mostly gone, but reported Sunday that investigators found a possible new source.
The Coast Guard says some recovered oil is awaiting analysis at a lab.