MBTA officials say the agency will enjoy the "longest period of labor stability since the 1980s" now that collective bargaining agreements are in place with every single affiliated labor union at the T.

The agency's higher-ups and union bosses took a victory lap Wednesday after striking a deal with MBTA Plumbers, which they said represented the final collective bargaining agreement of 16 to be ratified.

Officials said it's the first time since 2009 that all 28 MBTA worker unions have agreements in place at once, and that the four-year term for each contract will offer the longest stretch without any gaps in the last four decades.

"The success of the MBTA depends on a well-trained, motivated and empowered workforce," Gov. Maura Healey said in a statement. "That's why, from day one, our administration has been committed to partnering with labor to efficiently secure agreements that ensure workers receive competitive wages and benefits and strengthen our efforts to recruit and retain the best talent."

T leaders said the contracts were modeled on an agreement reached in August 2023 with Boston Carmen's Union ATU Local 589, the largest workers' union at the MBTA. That deal included pay raises, retention bonuses and more benefits, and officials have credited it as a linchpin of a hiring campaign that has increased the MBTA's headcount by more than 1,100.

MBTA officials rolled out the news Wednesday with statements of support from T and Healey administration officials as well as a trio of top union leaders, including Massachusetts AFL-CIO President Chrissy Lynch.