HEAVENER, Okla. – The National Labor Relations Board (NLRB) set aside the results of a union vote at OK Foods Inc.'s Heavener, Okla. plant.

The United Food and Commercial Workers Union Local 1000 had been working with employees to unionize OK Foods since 2013. A vote to decide on unionization was held in May, but workers voted down the proposal. UFCW 1000 protested the vote on allegations of tampering by OK Foods executives.

The NLRB ruled that OK Foods "engaged in objectionable conduct" by making promises of higher wages and benefits to workers who voted against unionizing the plant.

"More specifically, credible evidence warrants the conclusion that the employer promised employees a wage increase in return for their support in the election, told an employee that it could not resolve his wage complaint because of the employees' union activity and solicited employees' grievances and promised to remedy them," the Board said in its ruling. The Board also called for a new union vote.

OK Foods is a subsidiary of Celaya, Mexico-based Industrias Bachoco, a leading poultry producer that employs more than 25,000 workers.