Sen. Ed Markey’s (D-Mass.) office is set to become the first in the Senate to unionize, after the Massachusetts Democrat was asked for formal recognition on Wednesday.

“Today we are unionizing the United States Senate,” the Congressional Workers Union said in a tweet. “100% of @SenMarkey staffers have come forward and requested voluntary recognition. Once recognized, this Office will be the first ever unionized United States Senate office!”

Markey voiced his support for the staffers’ effort in a Twitter post on Wednesday.

“I applaud these workers who are exercising their right to organize, a fundamental exercise in democracy,” the senator said. “I’m proud of their commitment not to agonize, but to organize. I recognize their effort to unionize and look forward to engaging with them.”

While the House passed a resolution in May allowing its staffers to unionize, a similar effort never cleared the Senate, which means Senate staffers are not subject to federal labor laws that protect workers from retaliation for organizing.

By formally recognizing the union, Markey would essentially pledge to follow federal labor laws, according to Roll Call. However, his staffers would not be able to seek redress with the Office of Congressional Workplace Rights or the National Labor Relations Board, Roll Call noted.