For the third time this year, a former Boeing South Carolina employee has filed suit against the aerospace company alleging retaliation for reporting racism in the North Charleston campus paint shop.

Boeing has denied the claims and is defending them in federal court.

According to the latest suit, Otis Cotton Sr. began working at Boeing in fall 2009 and soon faced racially hostile comments, including a co-worker “singing about putting a rope around the neck of a black person and hanging him from a tree.” Cotton claims he complained to management but “received no relief.”

“Instead, [Boeing] allowed and condoned unlawful retaliation against the Plaintiff,” the suit states. “This included [Cotton] being singled out to perform punitive and unsavory jobs such as sweeping the floor in the paint hangar daily, changing dirty filters and prohibiting him from painting, the job he was hired to do.”

According to the suit, Cotton “feared for his life and safety” and his mental health “suffered substantially.” He was “compelled” to quit in February 2010 and now lives in Georgia, according to his attorney, Ben Mabry.

“If these allegations are proven to be true, it would suggest that the Boeing Company needs to pay careful attention regarding the conduct of … a segment of its employees in the treatment of African-Americans,” Mabry said Wednesday.

The Columbia attorney is also representing Allen Adgerson of Orangeburg County, who sued Boeing in January, and Dorchester County resident Paulette Gilmore, who sued in April.

Both claim they were fired in retaliation for their reports of racist remarks, but Boeing claims they were terminated for legitimate reasons. Like Cotton, they seek back pay, punitive damages and attorney’s fees, among other damages.

“We believe the three lawsuits filed by Mr. Mabry lack legal merit,” Boeing South Carolina spokeswoman Candy Eslinger wrote in an email Wednesday. “Boeing does not discriminate nor tolerate employees who do, and will aggressively defend its position during every stage of the legal process.”

More than 6,000 people work at the local plane-making operation near the Charleston International Airport.

The first S.C.-built 787 Dreamliner rolled out of the final assembly building in late April and has now taken several test flights. But its customer, Air India, has been mired in financial and labor strife and has yet to take any of the 27 Dreamliners it has on order.

Boeing South Carolina officials had predicted a June delivery to the Indian national carrier but have yet to provide a date.