General Mills plant workers in Cedar Rapids, Iowa, voted down a contract, setting the stage for a strike.
The Retail, Wholesale, and Department Store Workers Union, which represents about 520 nonsalaried workers at the facility, said late Wednesday that 99% of them voted against the contract.
Union leaders cited management's unwillingness to offer real job protections and wage increases.
"I've worked at General Mills for over 38 years, I've stared them directly in the eyes through months of contract negotiations and I am stunned, to say the least, by their 'last, best and final' offer on our contract," employee Tim Sarver said in a statement.
The workers produce Cheerios, fruit snacks and Betty Crocker frosting at the plant.
Workers at Cedar Rapids voted to unionize in January, citing a gradual whittling of their benefits and job protections. At that time, plant workers spoke of a desire to work together with the plant's management and the intention for it to be a respectful campaign. The negotiation process recently turned sour. This is the first attempt at establishing the contract for the workers since unionizing.
RWDSU didn't disclose details of the company's offer, but characterized it as "an empty contract."
General Mills said it expanded its short-term disability program, parental leave and family caretaker policies last summer. As a result, the company said, it made changes to other leave programs at some locations.
"General Mills Cedar Rapids facility is a leading provider of competitive pay and our paid leave benefits are best in class," said Kelsey Roemhildt, a General Mills spokeswoman.
The union said it will initiate a strike unless the company moves on four key provisions left out of the last offer: wage increases that are more than marginal, overtime pay, protecting jobs against outsourcing and guaranteed benefits that can't be changed in the middle of the contract period.
The workers are members of RWDSU Local 110, which also represents about 700 plant workers at a Quaker Oats facility in Cedar Rapids. The Quaker Oats workers reached a tentative contract agreement with that company earlier this week.
"Cedar Rapids, Iowa, was built on cereal, and General Mills cereal needs to ensure our city continues to thrive," Roger Grobstich, vice president of RWDSU, said in a statement.