GRAND FORKS, N.D. (AP) — Locked-out workers at American Crystal Sugar Co. factories in North Dakota, Minnesota and Iowa will vote for a third time on the company’s contract offer.

The vote is scheduled for June 23, union spokesman John Riskey said. Union members overwhelmingly rejected the contract offer last July 31 and Nov. 1, saying it takes away too much job security and that wage increases would be offset by health insurance costs.

The decision to hold another vote came after representatives of the two sides met last week for a fourth time with a federal mediator but were unable to end the impasse. The company — the largest sugar beet processor in the country — is standing by its final offer, saying it is fair.