Sentence:  In support of the emphasis placed by the Department of Defense on instruction in emergency medical care , the Medical Illustration Service developed casualty simulation kits and rescue breathing manikins which are being <WSD>field</WSD> tested ; and overhead projector transparency sets on the subjects of Military Sanitation : First Aid for Soldiers ; Bandaging and Splinting ; the Emergency Medical Treatment Unit , Phase 1 , ; and Emergency War Surgery in support of the North Atlantic Treaty Organization ( NATO ) Handbook . 
Meaning of the word marked with <WSD> tags:  test something under the conditions under which it will actually be used