The union for striking Detroit Water and Sewerage Department workers says it will continue the walkout until the city gives amnesty to 34 workers threatened with firing.
The union struck Sunday to protest Detroit's plan to downsize the department and eliminate most of the jobs in the department over several years.
On Monday, department Director Sue McCormick wrote to 34 strikers that they're being suspended and face firing because they "engaged in gross misconduct that endangered public health and safety."
It's illegal in Michigan for municipal workers to strike.
American Federation of State County and Municipal Employees Local 207 said Wednesday that its executive board voted not to end the strike until the department agrees to amnesty for the 34, who work at a wastewater treatment plant in southwest Detroit.