NEWARK, N.J. » The Transportation Security Administration today proposed firing 25 employees at Newark Liberty International Airport and suspending 19 others as a result of an investigation into improper screening of checked luggage.

The alleged screening failures at one of the New York area’s three major airports were uncovered late last year after surveillance cameras were installed in one of its 25 screening rooms to check for possible thefts, the TSA said.

Eight employees were fired in June in the investigation. The latest action raises to 52 the number of TSA employees at Newark caught up in the investigation, making it the biggest single disciplinary action taken by the TSA at a U.S. airport.

The latest group cited includes screeners, as well as managers accused of failing to effectively supervise their employees.

All the screeners cited for failing to follow procedures were removed from their jobs in November and December and given non-screening duties pending completion of the investigation, the TSA said.

The TSA, which has more than 1,400 employees at Newark, said the screeners failed to ensure bags were properly screened before flights departed, but it did not provide more detail.

“The decision to take disciplinary actions today with the proposed removal of 25 individuals and suspension of 19 others reaffirms our strong commitment to ensure the safety of the traveling public and to hold all our employees to the highest standards of conduct and accountability,” said Lisa Farbstein, a TSA spokeswoman.

The theft investigation, which the TSA said was the reason the cameras were installed, did not lead to any charges. The TSA said an employee who was a suspect in that probe ended up resigning, though the cameras were left in place, turning up the screening lapses.

The previous biggest disciplinary action taken by the TSA was last year at Honolulu International Airport, where 48 employees were recommended for firing or suspension, also for failing to properly screen luggage.

All 44 employees cited today have the right to appeal. The proposed suspensions would for up to 14 days, and without pay.