Months after American Airlines flight attendants first started complaining that their new uniforms were causing some people to break out in hives and suffer itchy rashes, the union that represents the workers has filed a formal grievance with the airline.

The Association of Professional Flight Attendants sent a letter [PDF] to the airline’s general counsel on Wednesday, asking that the carrier either stop issuing the uniforms or let flight attendants stick with the old outfits. In addition, APFA wants American to reimburse any uniform-related health-care costs and earmark $2 million toward investigating the uniforms.

“As of today, nearly 2,200 Flight Attendants have reported reactions through our uniform reaction report form— with more coming each week. That represents nearly 8% of our workforce. This is a serious problem,” writes APFA’s director, Bob Ross.

Though American has agreed to conduct more tests and has allowed workers the option of returning to their “blues,” Ross says he filed the formal grievance because he doesn’t believe the carrier is taking the problem as seriously as it should.

“These uniforms continue to put our members at risk, forcing them to use sick leave and affecting their overall health, plus potentially the health of their colleagues with whom they com in contact at work,” Ross writes in the letter.

He goes on to formally protest the company’s actions with respect to the uniforms, citing the joint collective bargaining agreement between the airline and APFA.

One section of that agreement reads, “The Company will work with the Union Uniform Committee to expeditiously [emphasis APFA’s] resolve concerns over uniform designs/manufacturing defects.” Other sections recognize that the two sides should work together in a “cooperative manner regarding safety issues,” and that the company has an obligation to meet to “study and evaluate matters relating to the safety, health, and security of Flight Attendants.”

“Despite these contractual guarantees, and the Company’s knowledge that the new uniforms are adversely affecting the health and safety of many of our flight attendant in mass numbers daily, the Company has continued to issue the new uniforms.”

APFA’s goal is to give all flight attendants the permanent option of choosing for themselves which uniform they want to wear, and full reimbursement for replacements. If that proves “impractical,” the union wants American to recall all new uniforms.

American Airlines says it’s tested the uniforms three times and will conduct a fourth test with the union, a spokesman told Bloomberg. The company has also created a call center for complaints about the uniforms, and about 300 attendants have reported experiencing a reaction, he said.American will cover the cost of dermatological testing for employees who have experienced adverse reactions, and will respond to APFA’s letter within 20 days.

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