Seattle EMTs have voted to strike later this month, unless they can agree on a new contract with American Medical Response.

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The local Teamster’s union has approved the walkout by more than 400 EMTs and paramedics in the Seattle area.

Without a contract by noon on December 21, all union AMR employees plan to drop everything they’re doing, return their ambulances to their stations, and go home. The only exception, they say, would be if they were transporting a patient with life-threatening injuries.

The union says wages start around $15 an hour. In its latest offer, AMR offered to bump that to $17 an hour. The union argued that rate was barely over minimum wage and not enough to live on in Seattle.

“The wage demands made by the Union falsely led AMR employees to believe that patient charges could support up to a 67 percent wage increase,” AMR claimed in a news release.

According to AMR, Seattle EMTs are asking for a level of pay equal to that of their San Francisco counterparts, described by the company as “one of the nation’s largest 911 systems.”

The notable difference between San Francisco and Seattle’s EMT’s: The latter does not provide on-site medical care and largely is used to transport non-life-threatening patients to local hospitals. Seattle’s fire department is responsible for life-threatening emergency treatment and transport.

AMR also noted that its EMTs are not paramedics and “are not trained to provide advanced life support.”

Seattle Councilmember Teresa Mosqueda spoke out in favor of Seattle’s EMTs in a statement released Tuesday.

“Strikes happen for a reason. Strikes aren’t easy on workers, on their families or on their community. We stand with you,” she said.