The plane, which was flying from Baltimore to San Francisco, made an emergency landing at Dulles International Airport after a fuel odor was reported.
United said in a statement to WJZ 13 News that there was a “strong odor” in the cabin of the Boeing 737 after takeoff.
According to the outlet, four passengers were taken to a Reston, Va., emergency room but were not admitted to the hospital. WJZ 13 also reported that one person was discharged and another three were pending discharge.
Passengers on the flight took to social media to describe the smell of fuel, which reportedly triggered chest pains, headaches and nausea.
There has been no impact on airport operations, officials said in the statement.