Allina Health hospital nurses will vote Thursday on whether to approve a three-year contract that would begin to phase out their union-protected health benefits, or potentially authorize a second strike — this time an open-ended walkout that would continue until the contract standoff was resolved.

The Minnesota Nurses Association, which represents roughly 4,800 nurses at five Allina metro hospitals, is recommending a vote to strike, arguing that the health system hasn’t made enough concessions in areas of staffing and nurse safety and has failed to meet the union’s health insurance demands.

An open-ended strike would be the first in the Twin Cities since Fairview nurses walked off the job for three weeks in 2001.

“It’s scary for a lot of nurses,” said Angela Becchetti, a nurse at Abbott Northwestern Hospital in Minneapolis who serves on the union bargaining committee, “but we’re more scared about what they can do and how they can take our voice away.”

The first strike was limited to seven days in June; Allina’s financial report for the first half of 2016 shows it cost the health system $20.4 million to weather the walkout by hiring replacement nurses recruited from around the country.

A longer strike could be exponentially more expensive, but health system leaders said they are prepared for that contingency in order to hold firm on their demand that the nurses transition to Allina’s corporate health plans with financially sustainable benefit designs.

Allina executive Dr. Penny Wheeler

“To accept a health plan that is arcane and unsustainable? That doesn’t make sense to us as an organization for the long haul,” said Dr. Penny Wheeler, Allina’s chief executive officer and president, who met with nurses this week to outline the benefits being offered in the contract proposal up for a vote.

Allina believes switching nurses to its corporate plans would save $10 million per year. The corporate plans have lower premiums than the union plans, but also higher copays and deductibles that encourage efficient spending on health care — such as buying generic drugs instead of expensive brand names.

Wheeler said the contract offer represents a compromise from Allina’s initial stance to eliminate all four union plans.

Instead, it would retain the two union plans that are the most popular, but cap Allina’s responsibility for any cost increases to those plans at 2 percent per year. In addition, new nurses would not be able to enroll in the remaining union plans.

Wheeler acknowledged that the union plans would fall out of favor over time as costs to the nurses grew and veteran nurses retired.

“We knew a transition off the pricey Cadillac health plans was going to be necessary,” she said, “but we made a compromise that was really going to preserve choice.”

Nurses argued that the union plans and their low deductible benefits are uniquely important, given the high rate of workplace illnesses and injuries that come with their profession. But they also sought changes to improve workplace safety and increase nurse-to-patient staffing, and Becchetti said the current offer doesn’t address those demands.

Allina normally negotiates with nurses in lockstep with the Fairview, HealthEast, North Memorial and Children’s hospital systems, but opted to take on the health benefits issue this time while the others agreed quickly on contracts that only changed wages.

Vote results could vary by the hospitals: United in St. Paul, Mercy in Coon Rapids, Unity in Fridley, and Abbott and the Phillips Eye Institute in Minneapolis.

As a result, nurses at some hospitals could elect to strike while others could accept Allina’s offer. A two-thirds majority vote to reject the contract is needed to authorize strike planning at any hospital.

The union has filed more than two dozen claims with the National Labor Relations Board this year, claiming unfair negotiating tactics by Allina during contract talks — a move that among other things protects nurses from being replaced outright during any strike.

The board in late July rejected some of the claims, which alleged that Allina had not been forthcoming with information that the union needed to analyze its contract proposals. Others are pending.

A second strike in a single contract negotiation cycle is unusual. One of the most high-profile examples involves junior physicians with the British National Health Service, who have gone on strike six times.

Twin Cities hospital nurses from many systems voted to pursue a permanent strike in 2010 after a one-day walkout. However, the hospitals and nurses reached a deal before a second strike occurred.