The Minnesota Nurses Association on Tuesday called for nearly 5,000 Allina Health nurses to authorize an indefinite strike against five Allina hospitals. A vote is set for Aug. 18.

The move comes a day after contract talks between the union and hospital system broke down again. The nurses' health plan remains the main sticking point.

In June, Allina nurses went on strike for seven days at Abbott Northwestern Hospital in Minneapolis, Mercy Hospital in Coon Rapids, Unity Hospital in Fridley, United Hospital in St. Paul and Phillips Eye Institute in Minneapolis.

The decision this time to seek an open-ended strike is intended to put more pressure on Allina, said union spokesperson Rick Fuentes.

"The nurses are committed," Fuentes said. "When they take the vote, they know that this will be a very serious vote that, yes, will affect their life and livelihood. But this is a big decision that they are prepared to make."

Meetings to prepare the nurses for an extended walkout have already begun, Fuentes added.

The hospitals are preparing for another possible walk out but there remains time to negotiate an agreement, said Allina spokesperson David Kanihan.

"We don't want a strike. We don't believe a strike does any good to anyone's cause here," Kanihan said. "We want to reach a settlement. And we hope the union will reconsider and engage with us on this."

The nurses are insisting on keeping the insurance plan they have through the union. To cut expenses, the company wants them to switch to a corporate plan that 30,000 other employees use called Allina First. Nurses say they fear out-of-pocket expenses will skyrocket under Allina First.

A super-majority of nurses is needed to authorize union negotiators to call a strike. The union would have to give the hospital system 10 days' advance notice before striking.

The union's move is something of a gamble. The legal basis for the strike is the union's contention that Allina has engaged in an unfair labor practice. But so far, that's just an allegation.

If the National Labor Relations Board rejects that claim, and the nurses are on strike at the time, Allina could permanently replace them.

Allina is readying for an open-ended strike in much the same way it prepared for the one-week walk out in June, Kanihan said.

"We will be required again to bring in temporary nurses," he said. "Those nurses did an excellent job for us in our communities last time around. But let me say this: We don't want a strike."

A national mediator is involved in the dispute. While no new talks are currently scheduled, both sides say there's plenty of time to resume talks before a walkout.