The union representing New York City’s sanitation workers said on Wednesday it would sue the Adams administration to demand backpay for workers who failed to comply with the city’s COVID-19 vaccine mandate.

Harry Nespoli, president of the Uniformed Sanitationmen’s Association, said the union planned to sue “as soon as possible” on behalf of members who lost their jobs over the vaccination requirement.

On Monday, Mayor Eric Adams said he would lift the mandate for municipal workers — amid sprawling litigation from workers at various city agencies who have challenged the policy since it took effect in October 2021.

“Now they want to turn around and drop the mandate, but what about all that revenue that was lost by families?” Nespoli said in an interview.

The directive making the vaccine optional for city workers will take effect on Friday.

The lifting of the city’s mandate for its own workforce came after most policies designed to combat the spread of the virus had been relaxed by Adams in the past year. The mandate for private-sector workers ended last November, months after Adams ended a similar requirement for performers and athletes in local venues.

“I didn’t understand why they turned around and lifted it for the elite, for the ball players. I don’t know why they lifted that — but they did — and not city workers,” Nespoli said. “It’s something that should have been done together.”

“All municipal employees had to comply with the city’s Covid-19 public sector vaccine mandate because it was a condition of employment, which courts have upheld,” said a spokesperson for the city’s law department, adding that the mandate "was an overwhelming success."

“Employees who were terminated for failure to show proof of vaccination, will have the opportunity to apply for reinstatement or rehire. We will review the case," the spokesperson said.

Adams has made the city’s economic recovery from COVID-19 central to his agenda — but municipal workers and their unions have bristled at the city’s enforcement of a mandate few were still subjected to.

The administrations of Adams and his predecessor, former Mayor Bill de Blasio, have faced a barrage of litigation from members of the municipal workforce challenging the now-retired mandate.

In October, a Staten Island judge ordered that 16 sanitation workers be reinstated to their posts at the department and given backpay, which the city promptly appealed.

A Manhattan judge ordered the reinstatement of NYPD employees in a similar legal challenge one month earlier.

Nespoli said his union’s lawsuit would demand backpay for workers who lost their jobs at the sanitation department after refusing the vaccine. He said the union would also seek to get those workers reinstated.

This story has been updated with comment from the city's law department.