The maker of the uniforms worn by flight attendants for American Airlines claims its garments are safe to wear, despite worker complaints that they cause allergic reactions.

American first rolled out the new uniforms in September to 70,000 staff, and quickly received complaints about the gray wool garments. The reactions reported have ranged from hives and itching to eye irritation and respiratory problems.

The uniform maker, Twin Hill, called the claims by the union that represents American's flight attendants "inaccurate and damaging" to the company's reputation in a letter to the Association of Professional Flight Attendants.

It's the first time that Twin Hill has publicly addressed the controversy surrounding the new uniforms since complaints first emerged in the fall.

American (AAL) has consistently asserted the uniforms are safe to wear. The airline has received official complaints from around 450 staff, who have been permitted to wear the older uniform or receive reimbursement for purchasing their own off-the-rack replacements.

American Airlines flight attendants want new uniforms recalled

Testing done by the manufacturer and the airline, found "there are no restricted chemicals in the garments and that the chemicals that are present are well within acceptable standards for the clothing industry," Twin Hill said in its letter to the union.

American and Twin Hill have completed three rounds of testing, an airline spokesman said. But the union wants to have them tested by an independent organization.

The union did not respond to a request for comment.

An American Airlines spokesman declined to comment on the letter.

The flight attendants' union, which represents 26,000 staff at American, asked in December for the the new uniforms to be recalled.

Alaska Air Group (ALK), parent of Alaska Airlines, dropped Twin Hill as a uniform vendor after its own flight attendants complained about similar reactions after they were fielded in 2011. A 2012 lawsuit filed by 164 flight attendants claimed the uniforms caused their reactions. In October, Twin Hill won a court verdict that rejected those claims.

Twin Hill is a unit of Tailored Brands (TLRD), which also owns retailer Men's Wearhouse.