An overheated circuit board at a Washington, D.C., area radar facility grounded four airports Friday while the source of the chemical odor was investigated, officials said.
Ground stops were issued for the four area airports around 6:30 p.m., and were lifted by around 8 p.m., according to authorities.
Flights were halted at Ronald Reagan Washington National Airport; Washington Dulles International Airport; Baltimore-Washington International Airport; and Richmond International Airport.
The odor, a “strong chemical smell,” was affecting air traffic controllers at the Potomac TRACON, which stands for Terminal Radar Approach Control, the Federal Aviation Administration said.
“There is no danger to air traffic controllers,” Transportation Secretary Sean Duffy said on X after the ground stops were lifted. “The source of the strong odor was traced to a circuit board that overheated, and it was replaced,” he said.

Airports warned there could be residual delays Friday evening even though the ground stops had been lifted.
“Airlines are once again resuming regular operations and preparing departures. Expect residual delays this evening,” Baltimore-Washington International Airport announced on X at 8 p.m.
The Potomac TRACON building that experienced the trouble is in Northern Virginia, it said.