Senior Airman Gregory Rackley, 56th Bioenvironmental Engineer technician, pours sensitivity solution into a nebulizer before a protective mask fitting test April 1, 2020, at Luke Air Force Base, Ariz. Sensitivity and fit test solutions are bitter liquids the bioenvironmental section sprays on N95 respirator masks to test their seal. Individual wearing the cover will taste the solution if the seal is faulty. Bioenvironmental personnel are fitting masks to minimize possible exposure to COVID-19 for medical personnel to continue care for patients. (U.S. Air Force photo by Senior Airman Leala Marquez)