OMAHA, Neb. — Work at all of the Kellogg Company’s U.S. cereal plants came to a halt Tuesday as roughly 1,400 workers went on strike, but it wasn’t immediately clear how much the supply of Frosted Flakes or any of the company’s other iconic brands would be disrupted.

The strike includes plants in Omaha, Neb., Battle Creek, Mich.; Lancaster, Pa.; and Memphis, Tenn.

The union and the Battle Creek-based company have been at an impasse at the bargaining table for more than a year, said Daniel Osborn, president of the local union in Omaha. The dispute involves an assortment of pay and benefit issues such as the loss premium health care, holiday pay and reduced vacation time.