The union that represents the MBTA’s contracted janitors Wednesday praised the new agreement between the MBTA and S.J. Services as “a step in the right direction.’’

“We commend the MBTA board’s attempts to right a wrong and agree to increase janitorial staffing at the T,’’ Roxana Rivera, the vice president of the union, 32BJ SEIU, said in a statement. “We have always stated that laying off janitors who provide essential services to the T could only result in poorer service, overburdened workers, and unhappy riders.’’

Union representatives learned about the new agreement March 17 during a meeting with S.J. Services, Rivera said.

The MBTA announced Tuesday it had reached a new agreement with S.J. Services, its main janitorial company, to make 30 employees full time, making them eligible to receive health insurance.

The new agreement calls for S.J. Services to add two supervisors and provide 70 more hours of cleaning services a week.

S.J. Services and a second janitorial firm contracted by the MBTA have drawn controversy by cutting the hours for dozens of their employees, making them ineligible for health insurance.

In 2013, nearly 300 janitors were employed by the MBTA, Rivera said.

That number has since dropped off sharply, she said.

“We do not want a repeat of the crisis that was felt by so many,’’ Rivera said. “We don’t want to go backwards on good jobs.’’

Maddie Kilgannon can be reached at maddie.kilgannon @globe.com. Follow her on Twitter @MaddieKilgannon.