(NewsNation) — A severe air traffic controller shortage is pushing those who remain to the brink, mentally and physically. But as working conditions continue to deteriorate, a new report by the New York Times revealed an increase in controllers asleep or under the influence of alcohol or drugs on duty.

The president of the National Air Traffic Controllers Association recently complained to Congress about understaffing and frequent overtime leading to fatigue.

The union and the Federal Aviation Administration revealed that 99% of the nation’s air traffic control sites are understaffed, the report said.

The New York Times reported that over the past two years, hundreds of complaints were submitted to the FAA hotline describing these issues related to the staffing shortage, mental health problems and physical issues with the work environments, including offices infested by bugs and black mold.

Among the complaints, there were at least seven reports of controllers asleep on the job and five reports detailing employees working while under the influence of alcohol or drugs, the New York Times reported.

Plus, air traffic controllers are forced to spend hours in dark spaces without opportunities for appropriate breaks, scanning monitors for airplanes that carry thousands of passengers across the sky, the report said. Many of the controllers have been subjected to six-day weeks and 10-hour days, according to the report.

As a result, air traffic controllers said they are fatigued, distracted and feel demoralized working in this field. Plus, these conditions have increased chances of making mistakes while on the job, leading to potential close calls, the report said.

The FAA has about 1,000 fewer fully certified controllers than it had 11 years ago, according to an investigative report by the National Airspace System Safety Review Team. Hiring fell by nearly half during the pandemic, and the agency’s training center in Oklahoma City is a “bottleneck,” the group concluded.

Now, the FAA estimates that more than 1,400 controllers will depart this fiscal year due to these conditions.

The NAS Safety Review Team report comes on the heels of the FAA‘s investigation into near-miss accidents with a nearly 25% increase over the past decade. About 300 of these accidents were reported in the last 12 months of the report.

Over the past year, the New York Times reported there were 503 “significant” air traffic control lapses, which was 65% more than the year prior.

After several of these close calls, including one in February in which a FedEx cargo plane cleared to land flew about 100 feet over a Southwest Airlines jet that was cleared to take off from the same runway in Austin, Texas, the FAA announced the NAS Safety Review Team investigative panel.

The aviation experts who examined the FAA’s safety record said the agency needs better staffing, equipment and technology to cope with a surge in the most serious close calls between planes.

“The FAA has made limited efforts to ensure adequate air traffic controller staffing at critical air traffic control facilities,” the experts said. The worst shortages are at key facilities in New York and Florida, which led the FAA to pressure airlines to reduce flights in the New York City area this summer and fall.

Controllers have also worked more overtime, which “introduces risk” into the nation’s airspace and leads to more absenteeism, lower productivity and fatigue, the panel said. Sometimes supervisors fill in when they should be supervising instead, the group wrote.

The government recently stepped up operations, hiring more air traffic controllers and opening new air routes along the East Coast ahead of the holiday travel season, U.S. Transportation Secretary Pete Buttigieg said last week.

However, the FAA recently blamed Congress for the long overdue changes needed for the country’s aviation system due to continuous political gridlock that led to “inadequate and inconsistent” funding for air traffic control.