Unionized nurses delivered a formal strike notice to New York City’s three largest hospital systems Monday, a sign that another big organized labor force is prepared to follow the nation’s teachers and walk off the job if their demands are not met.

If hospital management and the New York State Nurses Association cannot reach a deal by April 2, 10,000 nurses will stop showing up for work and start picketing. A near-unanimous 97 percent of members voted to authorize a strike at Montefiore, Mount Sinai, and NewYork-Presbyterian Hospitals.

In 2018, education and health-care professionals were the two most likely groups of American workers to go on strike, according to the Bureau of Labor Statistics, in a big spike over the previous year.

The big issue of contention for nurses is understaffing, which nurses say endangers patients. “After nearly 30 negotiation sessions, we still do not have a single item agreed upon,” the union said in a statement announcing the strike date. “But it is management’s continued refusal to even engage in a conversation about minimum nurse-to-patient ratios that has led to this moment.”

The union says that nurses are sometimes working with 9 or 10 patients at once, which creates safety issues for both health-care workers and the people who receive care. NYSNA, which has endorsed the Medicare for All policy in New York hospitals, said that its bargaining committee will be available to negotiate “every day and night” until the deadline. Members at the Brooklyn Hospital Center are voting this week on whether to join the strike, according to the union.

Michelle Gonzalez, a 29-year-old nurse at Montefiore Medical Center who serves on the union’s bargaining committee, told VICE News that the hospitals are more than wealthy enough “to staff the floors correctly.”

“The employers are getting away with understaffing and then blaming us when things go wrong,” Gonzalez said.

She also noted that hospitals are treating more patients who are getting sicker and living with chronic diseases like hypertension and heart disease as the years pass. The number of seniors with four or more chronic diseases will double by 2035, according to a recent study.

The New York Hospital Alliance, which represents hospital managers at the three systems, told VICE News in a statement that nurses were trying to “advance their political agenda” of staffing ratios.

"Our first priority is providing patients with uninterrupted health care,” the statement said. “We respect our NYSNA nurses and will continue to work to reach an agreement that is fair, reasonable, and responsible for all parties.

Workers and supporters held a rally at Mount Sinai Hospital on Monday to “demand safe staffing.” For years, nurses have lobbied for safer working environments. A 2014 survey found that 76 percent of nurses had experienced violence in the workplace.

Insufficient staffing is driving some nurses to leave the profession and causing high levels of turnover and retirement, according to the American Association of Colleges of Nursing. The American Nurses Association estimates that there will be more registered nurse jobs available through 2022 than any other American profession.

Hospital workers caused major work stoppages — strikes affecting 1,000 or more workers — at least four times in 2018, according to BLS, but the number of workers participating in the New York City strike outnumbers other recent nurse work stoppages by thousands.

In 2018, health-care and social assistance workers — about 75,000 of them — made up a big chunk of labor strikes, according to the Bureau of Labor Statistics.

Health-care and social-assistance workers (75,000) were second only to teachers, 375,000 of whom were the driving force of labor strikes last year, the first year the amount of striking workers went up in more than three decades. Together, the two workforces accounted for 90 percent of all major strikes in the U.S. in 2018.

To put it another way: In 2017, just 25,000 workers were involved in major work stoppages, according to BLS; in 2018, that number jumped to 485,000.