Detroit's Water and Sewerage Department took steps to fire more than 30 employees who started Sunday's strike at the wastewater treatment plant.

Department officials confirmed to the Detroit News that Director Sue McCormick sent letters to 34 employees notifying them of their immediate suspension and pending termination for illegally walking off the job.

"The letters, sent via certified mail, informed the employees that … they engaged in gross misconduct that endangered public health and safety by unlawfully abandoning their jobs at the plant," the department said in a statement.

"The 34 employees are suspended without pay and their employment will be terminated effective October 10. The individuals were ordered not to enter on to any (department) property and directed not to misrepresent themselves as department employees in good standing during the suspension period."

Read more: Detroit News