(NEW YORK) — More than 75,000 workers at Kaiser Permanente launched a strike Wednesday, with a coalition of unions alleging the health care system is engaging in unfair labor practices.

Employees in Virginia and Washington, D.C., walked off the job at 6 a.m. ET while those in California, Colorado, Washington and Oregon began striking at 9 a.m. ET, beginning the largest health care workers strike in U.S. history, the unions say.

Those in mid-Atlantic states will be striking for one day while those in western states will be striking for three days.

The strike includes hundreds of positions, including nurses, emergency department technicians, pharmacists, optometrists, home health aides, medical assistants, dental assistants and more.

The Coalition of Kaiser Permanente Unions, which represents more than 85,000 workers, said Kaiser is experiencing a short-staffing crisis and that unsafe levels of staffing can result in long wait times, patient neglect and missed diagnoses.

Additionally, the Coalition said it’s advocating for better medical plans for retirees as well as protections against work that is outsourced and subcontracted.

The Coalition and the nonprofit organization have been bargaining since April but were unable to reach an agreement before contracts expired on Sept. 30.

In a statement to ABC News on Wednesday, Kaiser said bargaining was ongoing and some agreements had been reached.

“Both Kaiser Permanente management and Coalition union representatives are still at the bargaining table, having worked through the night in an effort to reach an agreement,” the statement read. “There has been a lot of progress, with agreements reached on several specific proposals late Tuesday.”

The statement continued, “We remain committed to reaching a new agreement that continues to provide our employees with market-leading wages, excellent benefits, generous retirement income plans, and valuable professional development opportunities.”

Kaiser had said throughout the strike, all of its hospitals and emergency departments will remain open and contract workers have been hired to backfill striking employees.

The Kaiser strike comes amid several major labor actions in other sectors of the workforce. The United Auto Workers launched a strike on Sept. 15 against General Motors, Ford and Stellantis after failing to reach a contract agreement with the automakers.

Additionally, the Screen Actors Guild-American Federation of Television and Radio Artists (SAG-AFTRA) is continuing its strike against the Alliance of Motion Picture and Television Producers (AMPTP) which began on July 14.

The Writers Guild of America ended its strike against AMPTP last week after almost 150 days, securing better pay and regulations for the use of artificial intelligence in certain projects.

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