As many as 15,000 Twin Cities and Duluth hospital nurses could strike for three days, starting Sept. 12, if an agreement isn't reached on overdue three-year contracts.

Thursday's 10-day advance notice of a strike follows weeks of unsuccessful negotiations — with the two sides far apart on wage increases, staffing levels, and compensation and support after two and a half years of pandemic.

A "crisis of retention" motivated the strike decision, said Mary Turner, president of the Minnesota Nurses Association (MNA) and an intensive care nurse at North Memorial Health in Robbinsdale. Unless pay and benefits are substantially improved, the continued loss of nurses will leave hospitals dangerously understaffed.

"They need to see it as the crisis that it is," Turner said. "We've said over and over that this isn't something we do lightly, but we're not going to just sit back and do nothing. We can't."

The announcement will set off a scramble to hire replacement help at Allina, Children's and Fairview hospitals in the Twin Cities along with HealthPartners' Methodist Hospital in St. Louis Park and North Memorial. Nurses also would be striking at St. Luke's Hospital in Duluth and Essentia Health hospitals in Duluth, Moose Lake and Superior, Wisc.

Both sides agree on the need to improve recruitment and retention, but the hospitals contend the nurses' proposals are too costly. The nurses are seeking more than 30% increases in compensation by the end of the three-year contract while the hospitals have offered 10% to 12%.

"It just isn't a realistic number," said Paul Omodt, a spokesperson for several of the negotiating Twin Cities hospitals. Allina and Fairview hospitals are posting operating losses so far this year.

North Memorial nurse Brianna Hnath argued that the hospitals can't afford to wait to improve benefits and retention. Staffing shortfalls already resulted in a 14-hour wait at North Memorial's emergency department recently.

"If things continue as they are, this will become the new normal," she said.

Methodist nurse Victoria Zeehandelaar said an inpatient observation unit was closed Wednesday and patients moved out. Only two nurses were scheduled and they would have been required to care for eight to 10 patients each.

"We want to make sure our patients get the best care with the best possible outcomes," she said.

The MNA union justified the strikes in claims over the past week to the National Labor Relations Board (NLRB), arguing that the hospitals had engaged in unfair labor practices through their lack of serious negotiations this year. A strike based on unfair labor practices guarantees that nurses can return to work and receive back pay.

The hospitals filed counterclaims Thursday with the NLRB, arguing that the strike is not based on unfair labor practices and that the union as a result failed to submit a required 30-day notice to the state Bureau of Mediation Services. The hospitals hoped to delay the strike and buy time for negotiations.

Statements by the Twin Cities hospitals called the strikes "rushed" and urged the nurses to consider a federal mediator to bridge the gap in proposals. Turner said mediation is premature and usually brought in when a deal is close but the sides are stuck on final terms.

In addition to wage increases, the nurses are seeking recognition bonuses and mental health benefits to compensate for the hardships they endured during the pandemic. They also want increased security measures to deal with the increase in incidents involving agitated patients or relatives. Assaults have caused 31 disabling injuries to patients or workers of Minnesota hospitals since 2010, and 14 have been reported in the last two years, according to the state's hospital adverse event data.

While the nurses bargain individually with their own hospitals, they agreed collectively on the strike action to increase negotiating pressure on their employers. They chose a time-limited protest strike rather than an open-ended strike to create incentives for negotiating while limiting disruption to patient care. Turner said it would be the largest private sector nursing strike in U.S. history.

The action follows two strikes totaling 44 days by Allina nurses in 2016 in a dispute over health benefits. Twin Cities' hospital nurses also went on strike for one day in 2010.

A 2010 study by the National Bureau of Economic Research found about a 19% increase in patient mortality and a nearly 7% increase in re-admissions during nursing strikes.

Allina declined to provide details of the impact of the 2016 strike on patient outcomes but said the health system will be in stronger position to maintain patient care if a strike occurs in 2022. The pandemic forced hospitals to become adept at recruiting and training temporary help.

"As a system we are much more accustomed to working with travel nurses than we were in 2016," Allina said in a statement. "We are confident in our planning and our ability to provide safe care for the duration of a work stoppage."