GRAND FORKS, N.D. (AP) — Union workers in North Dakota, Minnesota and Iowa who have been locked out of their jobs for 20 months at American Crystal Sugar Co. approved a new contract Saturday.

Leaders of the Bakery, Confectionery, Tobacco Workers and Grain Millers International union said in a news release that the workers voted 55 percent to accept company management's contract offer. It was the workers' fifth time voting on the contract. Employees last voted on it in December, when 55 percent voted to reject the offer.

"This means Crystal Sugar's skilled, experienced workers will be transitioning back to the factories to start repairing the damage that's been done over the past 20 plus months," John Riskey, the head of a union local that represents employees at three American Crystal Sugar factories, said in the news release.

"BCTGM members thank all who have supported our stand for justice and dignity and who have helped our families survive these hard times."

Brian Ingulsrud, vice president of administration with American Crystal, told The Associated Press: "We're just pleased that the employees will be returning to work."

The new contract will run until July 31, 2017, or just over four years, according to the company. Returning union employees will receive a total pay increase of 13 percent over the course of the contract, with 4 percent the first year, 3 percent the second and 2 percent the remaining years.

Nearly 1,300 employees were locked out on Aug. 1, 2011, after rejecting the cooperative's proposed contract. Company officials say many of those workers have retired or resigned.

The company has operated the plants using replacement workers.

The union originally focused its complaints on provisions in the contract regarding seniority and job security. The company says it's a good contract with substantial increases in wages and other benefits.

Moorhead, Minn.-based American Crystal is a cooperative owned by about 2,800 sugar beet growers. It is the nation's largest sugar beet processor, selling 90 percent of its production to industrial customers, including candy makers, bakeries and breakfast cereal makers.

The lockout began after 96 percent of the workers voting on the company's contract proposal rejected the offer on July 31, 2011.

In subsequent ballots, 90 percent of the voting workers turned down the proposal in November 2011, and 63 percent rejected it in June 2012.