Eliminating the use of powdered latex gloves was the most effective strategy in preventing latex allergen exposure in healthcare workers sensitive to the substance, a new study reports.

Researchers followed 800 healthcare workers in two hospitals over a 4.5-year period, both before and after the hospitals switched to powder-free latex gloves. The powder used in these gloves is made of cornstarch, which previous studies have shown is an allergen carrier.

The Medical College of Wisconsin investigators also tested the levels of latex allergen in the air ducts of the employees’ primary work areas before and after the test sites implemented the switch to powder-free gloves. They were able to identify a substantial link between high levels of airborne allergen and healthcare workers with a latex allergy or sensitivity.

“This study provides the strongest evidence that allergic sensitivity to latex in healthcare workers is linked to airborne allergen exposure through powdered gloves,” said lead author Kevin Kelly, M.D. in a statement. “I believe these findings provide a roadmap for health care institutions that will help minimize the risks of latex sensitization to health care workers.”

About 25% of the workers studied are no longer considered sensitized to latex. But researchers are not certain how long this effect will last.

The study was published in the Journal of Occupational and Environmental Medicine.