The Federal Aviation Administration is getting an earful from U.S. officials and lawmakers, after reports Wednesday of another incident involving a sleeping air traffic controller -- the fifth such case this year, this time occurring during an emergency plane landing.

In response to the lapses, the FAA announced it was immediately putting a second controller on the midnight shift at 26 airports and a radar facility around the country that currently have only one overnight person.

"I am totally outraged by these incidents. This is absolutely unacceptable," Transportation Secretary Ray LaHood said in a statement. "The American public trusts us to run a safe system. Safety is our No. 1 priority and I am committed to working 24/7 until these problems are corrected."

FAA Administrator Randy Babbitt said in a statement, "Air traffic controllers are responsible for making sure aircraft safely reach their destinations. We absolutely cannot and will not tolerate sleeping on the job," 

Senate Majority Leader Harry Reid said on the Senate floor that he shares LaHood's and FAA Administrator Randy Babbitt's outrage.

"This shouldn't happen in Nevada. It shouldn't happen anywhere in the country," he said. "It shouldn't happen to any airplane. And it certainly shouldn't happen to an air ambulance."

Sen. John Rockefeller, chairman of the Senate Committee on Commerce, Science and Transportation, said he told the Babbitt in a phone call that he's "sick of this."

"I have the utmost respect for air traffic controllers, the vast majority of whom work hard and are outstanding professionals," the West Virginia Democrat said in a statement. "But we can't have an aviation system where some of the people responsible for safety are literally asleep at the switch. This has to stop. The agency needs to do whatever it takes to keep air traffic controllers from sleeping on the job or not treating their responsibilities with the highest level of seriousness and attention."

Rep. John Mica, chairman of the House Transportation and Infrastructure Committee, said he wasn't happy with FAA's decision to double staffing levels in response to the lapses.

"Only in the federal government would you double up on workers, averaging $161,000 per year in salary and benefits, that aren't doing their job," he said in a statement. "This increase in staffing, when there is little to no traffic, also misdirects our resources and focus away from congested air traffic control facilities."

The latest incident occurred early Wednesday in Nevada when an air traffic controller was asleep and out of communications for about 16 minutes while a medical plan was landing.

No one was injured when the flight carrying at least three people landed at Reno-Tahoe International Airport. The controller has been suspended while the FAA investigates his lack of response to repeated contacts from the plane and airport staff around 2 a.m. Wednesday.

An investigation by the FAA uncovered a second incident of an air traffic controller sleeping on the job in February during the midnight shift at McGhee Tyson Airport in Knoxville, Tennessee.

The agency also said a controller in Seattle had been suspended for falling asleep during a morning shift on Monday. The controller already faced punishment for falling asleep on two other occasions during an evening shift in January, the FAA said.

In addition, two controllers in Lubbock, Texas, were suspended after two failed handoffs two weeks ago.

LaHood previously ordered an examination of controller staffing at airports across the nation and directed that two controllers staff the midnight shift in Washington.

A separate investigation was ordered by the House Transportation and Infrastructure Committee.

Reid said the Reno incident was unacceptable and his office was asking the FAA that a minimum of two air traffic control personnel work in the tower at all times.

Airport chief Krys Bart said the pilot of the medical flight -- a Piper Cheyenne with seating for five -- and airport staff had tried to contact the controller multiple times without success. The FAA said the pilot was in contact with regional radar controllers in northern California during the landing.

"The pilot evaluated the airfield. The weather was clear. The aircraft did land without incident," Bart said.

It was not immediately clear where the flight was coming from.

Bart said the airport, which serves the Reno, Carson City and Lake Tahoe areas, opened a new air traffic control tower in October 2010.

She said the airport has three runways, including two with modern instrument landing and lighting systems.

The incidents come nearly five years after a fatal crash in Kentucky in which a controller was working alone. Investigators said the controller in Kentucky was most likely suffering from fatigue, although they placed responsibility for the crash that took 49 lives on the pilots.

The National Air Traffic Controllers Association has warned against putting controllers alone on shifts and assigning tiring work schedules.

At most airport towers, there's no bathroom in the cab -- the room on the top of the tower. With only one controller on duty, the position has to go unattended at times if the controller needs to use a bathroom. It's common for the nearest bathroom to be located down a flight of stairs from the cab.

The Associated Press contributed to this report.