WASHINGTON, March 27 (Reuters) - The Federal Aviation Administration said traffic was resuming at the three primary Washington, DC-area airports late on Friday after a strong chemical smell forced the evacuation of an Virginia air traffic control facility.

The FAA said controllers had returned to the Potomac Consolidated ​Terminal RADAR Approach Control or TRACON, which controls airspace over numerous airports in ​the Washington region.

The FAA issued ground stops at Reagan Washington National Airport, Washington Dulles, Baltimore and smaller airports in Charlottesville and Richmond around 6:40 p.m. EDT before lifting them about 90 minutes later.

The FAA said there would be continuing delays as air traffic returns to normal. FlightAware said 30% of arriving flights at Baltimore and National were delayed and 13% at Dulles.

The incident was the second time in two weeks an odor at the air traffic facility in Warrenton, Virginia has snarled air traffic.

Another strong smell prompted the FAA on March 13 to halt air ‌traffic. The FAA said then it had halted traffic because of a strong chemical smell tied to a circuit board that overheated, which had prompted fire departments to respond.