U.S. Air Force Airman 1st Class Jeffrey Cruz, 60th Aerospace Medicine Squadron Bioenvironmental Engineering Flight technician, conducts a fit test on Airman 1st Class Sara Marinelli, 21st Airlift Squadron loadmaster, April 10, 2020, at Travis Air Force Base, California. The bioenvironmental engineering flights conducts respirator and gas mask fit tests to protect Airmen and maintain a healthy workforce. They also perform environmental, occupational and radiological surveillance. (U.S. Air Force photo by Heide Couch)