The charge was one of two that Starbucks has filed against Workers United since the union began organizing late last year. More than 200 Starbucks locations have unionized since December.
The PRO Act would affect Starbucks employees’ struggles with the company’s alleged union-busting efforts.
Employees at the Starbucks locations on Seventh Street and Bell Road in Phoenix and 107th Avenue and Indian School Road in Avondale voted in favor of unionizing.
Federal labor officials have asked a judge to force Starbucks Corp. to reinstate three union activists at its Phoenix location.
Laila Dalton, a shift supervisor who was working to unionize the location at Scottsdale Road and Mayo Boulevard, was fired the day before union election ballots were sent out.
The site provides a place for Spanish-speaking workers to file unfair practice charges and petitions for union elections in their native language.
Arizona’s Sinema and Kelly are two of just three Democrat senators who haven’t cosponsored the labor rights legislation.
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