BROOKLINE — About 150 members of a municipal employees union circled Brookline Town Hall in the cold drizzle Tuesday night protesting what they say is the town’s unfair bargaining process.

Employees say the town backed out of an agreement reached Feb. 3 after a 10-hour negotiating session that ended with a formal memorandum of agreement and handshakes.

“We left town hall that night with a good-faith belief and the word of the town’s representatives that the agreement would be brought to selectmen for vote,’’ said Bruce Genest, local president of the American Federation of State, County, and Municipal Employees.

Instead, Genest said, after waiting a month for a response, the union was told the agreement was never brought to the Board of Selectmen for a vote, and that new terms were being put on the table.

“They reneged,’’ Genest said.

But Town Administrator Melvin Kleckner called the situation an “unfortunate misunderstanding.’’

“The town’s negotiating team and the union did not reach an agreement,’’ he said. “I’m not saying the union didn’t think there was an agreement, but the town’s negotiators weren’t authorized to sign anything.’’

Kleckner said the town’s negotiators were authorized only to bring the agreed-upon terms back to the Board of Selectmen, which they did.

The Board of Selectmen then sent their negotiators back to the bargaining table with slight changes, according to Kleckner, which Genest said “took some money off the table.’’

“We’re now at an impasse,’’ Kleckner said.

He said the town has filed papers with the state Division of Labor Relations requesting a third-party mediator work with the two sides to try and come up with an agreement.

The union has also filed papers with the state formally charging the town with “bad faith bargaining.’’

AFSCME represents more than 420 employees in several town departments, including public works, the library, health inspectors, clerical employees, crossing guards, and others, according to Genest.

“In my 27 years working in town, I’ve never seen the morale of its workers as low as it is today,’’ he said.

That sentiment was expressed at the hourlong rally outside Town Hall, and then at the selectmen’s meeting where union members wearing their green AFSCME T-shirts packed the hearing room holding signs that read, “It’s Time To Pay Up,’’ “It’s About Respect,’’ and “Keep Your Word.’’

When Genest went to the podium to read his prepared statement, union members all stood and turned their back to the board.

“For all of the workers you see here tonight, there are scores more not in attendance who expressed fears that their mere presence at this meeting would result in retaliatory discipline,’’ he told selectmen.

Ellen Ishkanian can be reached at eishkanian@gmail.com.