Inside the rural Ohio labs run by Battelle, a nonprofit research and development firm, scientists have tested explosives, experimented with atomic energy and worked with chemical nerve agents. But some of the group’s most critical work is now happening outside, in a parking lot.

Under a sprawling tent near the small town of West Jefferson, employees have spent the recent weeks decontaminating over 30,000 used face masks for doctors and nurses on the front lines of the coronavirus pandemic.

Each day, N95 masks collected from more than 100 hospitals, clinics, fire departments and nursing homes are treated for hours with a hydrogen peroxide vapor. Once cleaned, the masks are sent back to the same facilities to be reused.