ANCHORAGE (AP) — A union representing about 150 clerical and operations workers at one of Alaska’s largest utilities has served notice it could call a strike by the end of the week.

KTVA reports members of United Association Plumbers and Steamfitters Union Local 367 made the official notification to Enstar Natural Gas Co. on Monday.

The company says service wouldn’t be affected if employees strike since a contingency plan is in place.

Negotiations have been ongoing since January, but a deal hasn’t been reached.

Enstar would not detail sticking points, but the union says the company is attempting to cut health benefits and pensions.