More than a dozen janitors and custodians walked off their jobs at the Constitution Center offices in downtown D.C. on Wednesday afternoon.

The strike came after federal labor charges were filed earlier this month against Quality Building Maintenance Inc. – a cleaning company based in the District. Workers allege that they were harassed and illegally fired over their immigration status after trying to unionize with 32BJ SEIU, one of the largest property service workers unions in the U.S.

“They want to have a better life, a better job treatment, and that’s their right.” said Mauricio Lopez, the 32BJ Capital Area District Leader. “But this company is intervening with that. Instead of supporting them, or letting their worker do the right thing, they fire them and are doing other stuff.”

Workers gathered at the steps of Constitution Center – which houses tenants like the Federal Trade Commission – to protest the actions of their employer, as well as their current working conditions. Along with the federal labor charge, a complaint was also filed with the Occupational Safety and Health Administration (OSHA) alleging that QBM discourages workers from taking water or bathroom breaks. The complaint is asking OSHA to conduct an on-site inspection.

Alicia Cortez says working conditions have been difficult throughout her four years of employment with QBM. When she was pregnant and working, she says her employer would get upset whenever she requested time off for health appointments. Like others, she says it is difficult to take a bathroom break.

“They treat us like slaves, and there are other people who were fired just because we’re demanding our rights,” said Cortez, who was born in Guatemala.

Ana Hernandez, who is a U.S. citizen, says she’s among the workers who were fired for trying to unionize. Hernandez says she had been working for QBM for about two weeks when she and others handed a union petition over to their supervisor. According to Hernandez, the group of about five workers, all of whom are noncitizens except for her, were fired.

“These are reprisals that the company is taking against us, so we’re asking for justice,” says Hernandez.

Quality Building Maintenance Inc. did not respond to requests for comment.

According to 32BJ SEIU, over 85% of commercial office cleaners in D.C. are unionized and bargaining for a new contract that expires on October 15. Lopez says QBM is an outlier, and as a result workers don’t have access to protection that being part of a union brings, or access to company facilitated health insurance.

“It’s really a shame that QBM is doing this for the workers,” said Lopez.