A national chemical distribution company has been hit with five federal lawsuits since last year by current and former employees, alleging wage-and-hour theft and racial discrimination against its black workers.

The latest lawsuit against Univar USA, filed this week in a federal court in Houston, claims that two drivers, Elton Wilson and Michael Roberts, were regularly passed up for promotions,  compared to their white and Hispanic co-workers, and were treated aggressively by white supervisors throughout their tenure.

The Houston lawsuit follows four filed against the company by Valli Kane & Vagnini since last September.

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The complaints allege supervisors and co-workers used racial slurs to refer to former and current employees. They say staff displayed threatening behavior in the office, including hanging a stuffed monkey from a noose over a black worker's desk, and writing offensive graffiti on bathroom walls.

The lawsuits claim these actions were part of a corporate culture in which black employees were consistently overlooked for advancement opportunities, and retaliated against when they complained. A class action suit in Georgia claims the company did not pay a group of 10 former and current workers for overtime pay they should have received.

Jeff Carr, senior vice president and general counsel and secretary for Univar, called the cases meritless. A team from Ogletree, Deakins, Nash, Smoak & Stewart, led by shareholder Eva Turner, represents the company.

“Most of the allegations are vague and amorphous, and although they may be enough to satisfy the liberal pleading requirements, they do not form the basis for a successful lawsuit,” Carr said in a statement. “Univar has and will vigorously defend itself against these cases.”

Similar claims—about the use of nooses, racial slurs by supervisors and fellow workers, and other hostile behavior—have been the subject of federal lawsuits in the last year by the U.S. Equal Employment Opportunity Commission and other private attorneys on behalf of black workers. However, while gender discrimination charges filed by the EEOC soared this year, racial charges sunk, according to the latest data from the agency.

“It seems the issues of racial discrimination are not isolated, but rather it is apparent there is a pattern all the way up the chain,” Vagnini said of the lawsuits against Univar. He said he has many cases pending around the country for similar hostile work environments against black workers, where he said employers feel disinterested in solving racial discrimination issues.

The first lawsuit, filed in Dallas federal court, on behalf of workers Kethenus Gill and Raymond Forman, received some attention from local news stations. This prompted other workers in Univar operations around the country to reach out to the plaintiffs firm, Valli Kane & Vagnini partner James Vagnini said in an interview Friday.

Vagnini said he received calls from Georgia about a similar racial discrimination case and another that alleged an overtime violation for a group of workers, and then the Houston workers followed.

“These cases show that Univar's response toward these issues lacked any serious approach to resolve the problems,” said Vagnini, who has not ruled out a class action against Univar for the discrimination claims.

Kim Dickens, Univar's senior vice president and chief human resources officer, said that the company is “built on a foundation of respect,” reinforced every day at the company.