EPA employees who signed the letter say they knew the Trump administration was unlikely to welcome constructive criticism, but news of their suspension still came as a shock.

Two employees in the EPA’s Region 8 headquarters in Denver and one who works at the EPA’s National Enforcement Investigations Center in Lakewood are under investigation for signing the letter, said Kate Tribbett, vice president of the American Federation of Government Employees Local 3607, which represents Region 8 employees.

The Environmental Protection Agency (EPA) placed 139 employees on administrative leave Thursday after they signed a public “declaration of dissent” against the agency. The affected employees, described by the agency as “career bureaucrats,