The Trump administration notified eight employees of their termination on Friday following their decision to sign a letter dissenting from current policies at the Environmental Protection Agency (EPA), the Associated Press reports.

“The Environmental Protection Agency has a zero-tolerance policy for career officials using their agency position and title to unlawfully undermine, sabotage, and undercut the will of the American public that was clearly expressed at the ballot box last November,” the EPA said in a statement after the administrative leave notices were sent, according to The Washington Post, who first reported the firings.

The letter had hundreds of named and anonymous signers.

“Since the Agency’s founding in 1970, EPA has accomplished (its) mission by leveraging science, funding, and expert staff in service to the American people. Today, we stand together in dissent against the current administration’s focus on harmful deregulation, mischaracterization of previous EPA actions, and disregard for scientific expertise,” the letter read.

Agency spokesperson Carolyn Holran told the Post the letter contains misleading information and represents a “small fraction of the thousands of hard-working, dedicated EPA employees.” 

The Hill reached out to the EPA for comment.

The American Federation of Government Employees (AFGE), a labor union for federal workers, said the EPA firings were illegal.

“The Trump administration and EPA’s retaliatory actions against these workers was clearly an assault on labor and free speech rights,” Justin Chen, president of AFGE Council 238, said in a statement to the Post. 

“It is clear that the actions taken by management were baseless and meant to punish any modicum of dissent identifying potential harm to the American Public and violation of the Agency’s mission.”

Another AFGE president said the move was meant to intimidate fellow employees from speaking out against the current administration and agency heads.

“They are trying to intimidate employees into doing the agency’s bidding and making sure that they don’t go public when there is a time that the agency is not looking after human health and the environment,” Nicole Cantello, president of AFGE Local 704, which represents 1,000 EPA workers in Chicago, told the Post.

Six of the dismissed employees were on probationary status and two others were career employees, according to the AP.