Delta Airlines (DAL  ) employees are suing Lands End Inc. (LE  ) over health complications allegedly stemming from uniforms purchased from the company.

The lawsuit, filed by 500 current and former employees, including flight attendants, ticket agents, gate agents, and Sky Club workers, alleges that the uniforms are responsible for a litany of health problems now faced by the employees. Among the medical issues supposedly caused by the uniforms are rashes, hair loss, low white blood cell counts, migraines, breathing difficulties, and boils, among other issues. The pending litigation asserts that the chemicals used in the uniforms to make them waterproof, wrinkle and stain resistant, among other qualities, is the culprit behind the health problems faced by Delta employees. The lawsuit has pointed to a report by the National Institute of Occupational Safe and Health from June of last year to support their claim; the NIOSH concluded that chemicals used in the uniforms could be responsible for the health problems faced by employees.

The lawsuit against Lands End is only the second stemming from health concerns regarding the uniforms, with a previous lawsuit being filed in October. Lands End responded to the lawsuits stating that the symptoms "are not the result of any negligence, product defects, or breaches of any warranty attributable to Lands' End." Delta supports Lands End's conclusion, despite numerous complaints from its employees.

Health concerns stemming from uniforms are nothing new to the airline industry. In 2010, Alaska Airlines (ALK  ) issued new uniforms to its employees that supposedly caused similar problems with employees. A lawsuit was filed by employees against uniform manufacturer Twin Hill, a lawsuit that the company would later win. American Airlines (AAL  ) would issue new uniforms from Twin Hill to its employees in 2016; shortly thereafter, employees began to report similar health concerns. In 2017, American Airlines employees filed a lawsuit against Twin Hill.

While much of the current litigation has yet to reach any conclusions, research being conducted by a Harvard research group has found a correlation between the health problems faced by employees and the uniforms they wear, particularly flight attendants. The study showed a spike in health complaints after the issuing of the uniforms, and a sudden drop after their recall.