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Nearly 8,000 workers at 78 King Soopers and City Market grocery stores in Colorado will return to work starting Friday, after union leaders and management reached a tentative three-year work agreement.

The strike, which began January 12, was the nation’s second-largest in the last two years — behind only a five-week work stoppage by 10,000 auto workers at John Deere that ended in November.

The Kroger (KR)-owned stores remained open during the strike, using management, temporary workers and employees brought in from stores outside of the Denver area. It started after union leadership rejected the company’s offer to replace a recently expired contract.

“After months of negotiations and after our members walked out on strike, we have reached a tentative agreement with King Soopers/City Market that addresses the company’s unfair labor practices and ensures that our members will receive the respect, pay, and protection they warrant,” Kim Cordova, the president of United Food and Commercial Workers union Local 7, said in a statement.

Joe Kelley, president of King Soopers and City Market, added: “We are pleased that this agreement allows us to put more money in our associates’ paychecks and secures healthcare and pension plans. We look forward to welcoming back our associates and customers.”

Now, Cordova says, union “members have the contracts they deserve and can be proud of.” Union members will vote on the agreement Monday.

Clash over previous offer

Kroger had previously criticized the union for not allowing members to vote on the company’s final pre-strike offer, which the company said would have raised starting pay to $16 an hour. Checkers who are currently paid $19.51 an hour would have gotten raises totaling $3.10 an hour, or nearly 16%, over the three-year contract. Employees with 10 or more years of service also were due to get a $4,000 signing bonus, with less senior workers receiving $2,000, according to the company.

Neither the union nor management released terms of the tentative agreement reached this week.

But the union said the company’s previous offer included provisions that were worse than the recently expired contract, including creating a new subclass of gig workers, which it claimed would be used to reduce work hours and drain the company’s health fund for long-term employees. It also did not address worker concerns about Covid safety measures to protect both employees and customers, the union said at the time the strike started.

The number of strikes across the nation has increased in recent months. With a tight labor market, a record numbers of unfilled job openings and many employers reporting difficulty finding the workers they need, employees are flexing their muscle in collective bargaining talks, demanding deals better than what they may have been offered, or accepted, in past years.

Workers are flexing their muscle in other ways, too. In several instances union leaders have worked out tentative agreements with management, only to have rank-and-file union members reject them.

That’s what happened at John Deere (DE) last year when 10,000 employees rejected a tentative agreement, a move that initiated their strike. They then voted against a second tentative agreement before finally ratifying a third deal and returning to work in late November. There were also multiple no votes by 1,400 workers at Kellogg (K) before they voted to end an 11-week strike just after Christmas.

And even where tentative agreements are reached, they are approved by the narrowest of margins. In November, members of a union representing 63,000 film and television production workers voted by only 50.3% in favor of a deal that narrowly averted a massive strike at major studios.

The retail sector has very little in the way of union representation. US Labor Department statistics from 2021 show that only 740,000 retail employees — or 5% — are represented by a union, even less than the 7% of private sector workers who are unionized. Grocery stores are far more likely than other retailers to have union representation.

— CNN Business’ Chris Isidore contributed to this report.