Racial discrimination complaints against Southwest Airlines are piling up in St. Louis.

The local chapter of the NAACP sent a letter to the FAA and airport director, demanding a response to the claims made by African American employees.

Adolphus Pruitt, president of the St. Louis City NAACP, said Southwest Airlines failed to address what they’re calling a discriminatory and hostile work environment. He said former and current black employees have made at least 40 complaints that include allegations of being unfairly disciplined which have, in some cases, led to their termination. He said there have also been complaints of a racial slur being spray-painted or posted at the work facilities.

Pruitt said he hopes Southwest can resolve the alleged issues and said legal action has not been taken.

Southwest Airlines responded to the allegations with the following statement:

Southwest neither condones nor tolerates discrimination of any kind. We take these accusations seriously, and as with any complaint we are conducting our own internal investigation.

We are aware of the additional communication from the NAACP chapter and we have advised the airport that we are conducting an internal investigation.

Southwest Airlines is an Equal Opportunity Employer, and prides itself on an open and inclusive work environment that consistently ranks among the world's best places to work. We employ more than 54,000 People across the United States who provide the world's best hospitality to our more than 110 million annual Customers as they travel throughout the Southwest network. Our People are our greatest asset, and it is our goal to support our Employees and our Customers who come from all walks of life.