Lawmakers and union officials on Thursday voiced concerns about the MBTA’s plans to cut nearly 30 percent of its janitorial workforce.

Contracts awarded by the MBTA Board to SJ Services and American Building Maintenance call for a cut of 29 percent, or 90 workers, of the cleaning staff starting on Sept. 1, 2014, according to SEIU 32BJ, a union backing the workers.

Members of the remaining workforce, which currently numbers 300, could also have their hours cut.

“I want to say shame on [the state Department of Transportation] and shame on the administration that would balance the budget on the backs” of the lowest paid workers in the state, said Sen. Ken Donnelly (D-Arlington).

Transportation Secretary Rich Davey told the News Service in April that the contracts have performance-based standards, instead of staffing-based standards, for cleanliness, and he expected the companies to use more advanced cleaning techniques to meet the standards. Staff reductions are allowed in the contracts.

The MBTA’s board, struggling with a massive debt load and an aging infrastructure, voted in May to hike fares by an average of 5 percent.

Donnelly and other legislators participated in a legislative briefing on the cuts that appeared to double as a rally for the workers.

“I have 17 MBTA stations affected with this cutback in workforce and it’s very concerning to me,” Sen. Anthony Petruccelli (D-East Boston) said. “We’re very concerned about the quality of life effect, the public safety effect and obviously the burden this would place on displaced workers.”

Union officials said the cuts will result in dirtier MBTA stations. Roxana Rivera, district leader for SEIU 32BJ, said the MBTA has the ability to terminate the current contract and make bid for new contract. One janitor described having to clean coffee spilled onto platforms, blood on the floor and spit on the walls.

“Those of you who use it can imagine what we have to clean up,” said Jose Vasquez, a 33-year-old Roxbury resident, through a translator.

Reps. Dan Ryan of Charlestown and Tackey Chan of Quincy joined Donnelly and Petruccelli.