WASHINGTON — On-the-job naps should be considered as part of a plan to address fatigue by air traffic controllers, airline pilots and others who work overnight shifts, a National Transportation Safety Board member said Monday.

There is an abundance of scientific studies that show short naps of between 20 and 30 minutes refresh workers suffering fatigue and help them remain alert when they return to their duties, NTSB member Mark Rosekind said. Rosekind is an internationally recognized fatigue expert who formerly worked for NASA and directed a sleep research center at Stanford University in Palo Alto, Calif.

“It should be on the table for consideration,” Rosekind told reporters at briefing on prevalence of fatigue among transportation workers.

Since late March the Federal Aviation Administration has disclosed at least five cases of controllers falling asleep on the job. In two cases, the controllers were fired. Controllers have been suspended in the other cases.

The National Air Traffic Controllers Association, the union representing FAA’s 15,700 controllers, is pressing FAA to allow naps during overnight shifts and during the 20 to 30 minute breaks controllers typically receive every few hours during day shifts. The FAA’s long-standing practice has been to forbid any sleeping on the job, even while controllers are taking their break.

An FAA-union working group on fatigue among controllers recommended earlier this year that sleeping be allowed during daytime breaks and in prearranged conditions on overnight shift when there is another controller available to handle the duties of the napping controller.

FAA officials have said the recommendations are being reviewed.