Damage Controlman 3rd Class Daniel Reveles instructs sailors on the proper wear of gas masks during chemical, biological, radiological training aboard the amphibious transport dock ship USS Green Bay (LPD 20). Green Bay is part of the Peleliu Amphibious Ready Group and, with embarked 15th Marine Expeditionary Unit, is deployed in support of maritime security operations and theater security cooperation efforts in the U.S. 5th Fleet area of responsibility. (U.S. Navy photo by Mass Communication Specialist 1st Class Elizabeth Merriam/Released)