An outside audit has found serious security lapses at the Massachusetts Bay Transportation Authority’s cash-counting department in Charlestown, leaving the operation inadequately protected and at risk of theft and danger to its employees, according to the agency.

Doors to the building were often left open or without alarms, allowing unsecured access to an operation that counts nearly $200 million in cash a year, according to details released Tuesday from the review of the MBTA’s so-called “money room.’’

The audit found that a door to the vault room was duct-taped, cameras were removed or missing at guard stations, and keys to areas throughout the facility were not securely managed and inventoried, according to Brian Shortsleeve, the MBTA’s acting general manager.

Shortsleeve said in a statement that the review, completed by consultants at 4Demand, revealed “very serious and immediate security threats.’’ The agency has already changed some of its policies to address the problems, he said.

“I will continue to talk with the Fiscal and Management Control Board about whether handling cash is a business the T should even be in,’’ Shortsleeve said. “Other transit systems and public and private operations across the country have procured the services of cash management professionals.’’

The review found that security officials often did not check employee ID badges or licenses to carry firearms and workers didn’t have a proper inventory system that would keep track of keys to the building. Vendors and outside workers who regularly visited the building were often given the same access as cash-counting employees, according to the audit, which was first reported by the Boston Herald.

The agency has said it spends $10 million on the cash-counting operation to employ 78 workers, including the agents who move money between fare boxes and vaults.

The release of some of the audit’s findings comes after the agency has already said that the jobs in the department could be given to outside companies, as part of a plan that would also outsource warehouse and marketing jobs. Last week, the agency released its first request for proposals for outsourcing its warehouse operations.

Officials in June said that they must move quickly with privatizing the cash-counting department because of “variances’’ between how much the fare boxes and vending machines say they are collecting and how much cash is actually being deposited. A 2012 review by the state auditor found that the T failed to properly keep track of $100 million in five years, though the audit found no evidence of theft or lost money.

The “variances’’ led the agency to hire another outside auditor to investigate the accuracy of the agency’s fare boxes. Asked about the results of the audit, Joe Pesaturo, a T spokesman, said the review found that the fare boxes largely did not correctly report how much money is deposited.

T officials on Tuesday said that four top managers who oversaw the operation are no longer in those positions anymore and that executive managers had replaced union supervisors.

Officials said they also reinstituted employee and visitor security policies, which required bags to be checked, and instituted a rule prohibiting more than one door between the vault and the street being open at a time.

In addition, the T last month quietly hired an outside security firm, G4S, to guard the cash-counting operation, in place of the T’s police. The T pointed out that it paid Transit Police about $750,000 a year for security at the facility, while G4S security officers will cost about $400,000 a year. The building is now guarded by G4S and one transit officer.

The Boston Carmen’s Union, which represents many of the workers employed in the money room, blasted the audit. The labor group has been sending several workers to testify before the T’s Fiscal and Management Control Board, asking its members to vote against outsourcing jobs.

James O’Brien, president of the union, said that the problems at the money room stem from bad management practices, not the workers in his union.

“It’s disappointing that MBTA management is attempting to disparage money room workers so they can embolden an effort to privatize the operation,’’ he said.

Nicole Dungca can be reached at nicole.dungca@globe.com. Follow her on Twitter @ndungca.