More than 60,000 health-care workers on Thursday voted to authorize a strike against Kaiser Permanente if an agreement is not reached when their current contract expires Sept. 30.

Members of SEIU-United Healthcare Workers West voted 98% in favor of a strike over complaints that pay has not kept pace with inflation and understaffing has led to long wait times and the neglect of patients.

The California union’s more than 57,000 members include medical assistants, surgical technicians and social workers among other health-care professionals.

Some 4,000 health-care workers in Oregon and Washington state voted to authorize strikes against Kaiser later Thursday. In Colorado, 3,000 workers authorized strikes against Kaiser last week.

The labor groups are part of an umbrella organization called the Coalition of Kaiser Permanente Unions that represents 85,000 health-care workers in total. The coalition says the strikes, should they take place, would be the largest by health-care workers in U.S. history.

Kaiser Permanente is one of the largest nonprofit health plans in the U.S. with nearly 13 million members. It operates 39 hospitals and more than 600 medical offices across eight states and Washington, D.C.

The coalition entered contract negotiations with Kaiser Permanente in April. The unions’ last contract was negotiated in 2019 before the Covid-19 pandemic pushed the nation’s health-care system to the brink. There is a final national bargaining session scheduled for Sept. 21-22.

Dave Regan, president of SEIU-United Healthcare Workers West, said Kaiser has failed to negotiate in good faith and its proposals would make staffing problems worse.

“Nearly 60,000 frontline workers at Kaiser facilities have overwhelmingly voted to authorize a strike because we will simply not stand by as Kaiser violates the law and puts patients at risk,” Regan said in a statement Thursday.

Kaiser Permanente, in a statement Thursday, called the unions’ claims misleading and urged employees to resist any call for an actual strike. Kaiser said it has a comprehensive plan in place to ensure continued access to health care should a strike take place.

In late August, Kaiser called the strike threats “disappointing” and said union claims that it has not acted in good faith are “unfounded and counterproductive.”