UNION -- A federal labor agency filed a complaint this week against an Indian food company it says illegally discriminated against workers who tried to organize.

Deep Foods is the 38th largest private company by global revenue in New Jersey and the fifth largest in Union County, according to NJBIZ.

The National Labor Relations Board alleges the Union Township-based company fired four employees because they joined a workers' union. An in-house judge will hear the case in March.

The NLRB said in its complaint that company executives had promised its employees promotions if they did not join the union, told them to report all union activities to management and threatened them with job loss if they organized.

Representatives from the local chapter of the Retail, Wholesale and Department Store Union and from several advocacy groups met at the company's headquarters Thursday to deliver a letter, urging Deep Foods to reinstate the fired workers.

The company refused to address the organizers, who said they would keep pressuring Deep Foods to meet their demands.

Cesar Suarez, one of the employees named in the NLRB's complaint, said he moved to Newark from Ecuador 20 years ago and had been a maintenance worker at Deep Foods for five years before he was terminated.

Deep Foods workers sometimes were forced to work in 120-degree rooms or were given one 20-minute break in 10 or 11 hours on the job, according to Suarez.

"Things like that, we want to change," he said. "That's why we are here."

Local union president Tom Walsh said the company's ongoing failure to reinstate the workers was disheartening.

"We're dealing with a company that's one of the wealthiest private companies in the state of New Jersey, and they're doing whatever they can to affect these people's lives," he said.

In an email, Deep Foods labor counsel James E. Patterson said the company denies all allegations of illegal and wrongful conduct.

Marisa Iati may be reached at miati@njadvancemedia.com. Follow her on Twitter @Marisa_Iati. Find NJ.com on Facebook.