An Airman assigned to the 48th Aerospace Medicine Squadron Bioenvironmental Engineering flight checks the acidity levels of the drinking water at Royal Air Force Lakenheath, England, June 19, 2018. The 48th AMDS, Bioenvironmental Engineering flight uses engineering principles to check for pollutants and radioactive materials, implementing environmental protections, monitoring OSHA and NRC work safety standards and permits, and other duties to reduce health risks and dangers to Airmen. (U.S. Air Force photo/ Airman 1st Class John A. Crawford)