Also known as a unit crest or DUI, a Distinctive Unit Insignia is worn by all Soldiers (except General Officers) in units that have been authorized to be issued the device. It is worn centered on the shoulder loops of the Army Green Service Uniform (AGSU) and the blue Army Service Uniform (ASU, Enlisted only) with the base of the insignia toward the outside shoulder seam. DUIs are not worn on the Dress variations of either uniform, however.
More guidance on wear of the DUI is found in DA Pamphlet 670-1, Section 21-22, "Distinctive unit insignia" and 21–3(d) and (e), "Beret" and "Garrison Cap," respectively.
♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦
Brigadier General Carl Roger Darnall was a driving force behind the chlorination of drinking water to kill bacteria, viruses, and other pathogens, a process that has saved innumerable lives since its widespread adoption in the early 20th century. To commemorate his contribution to public health and also honor his military service, which included a two-year stint as Commanding General of the Army Medical Center, the Army decided in 1963 to rename the medical center at Fort Hood, Texas the Darnall Army Community Hospital.
On 9 September 1969, the Distinctive Unit Insignia for the U.S. Darnall Army Hospital was approved, but it was redesignated for the U.S. Army Medical Department Activity, Fort Hood on 30 August 1973. It was redesignated for the Carl R. Darnall Army Medical Center with an effective date 1 May 2006, the date the facility was given that new name.
A white star in the center of the insignia is a reference to the “Lone Star” state of Texas, where the facility is located. The green symbol superimposed over the star is a water bouget, a heraldic rendering of a device used by armies in the Middle Ages to carry drinking water; here the emblem symbolizes the historical importance of Darnall’s contribution to medical science. Green represents chlorine, while the blue bands below it symbolize water. Two serpents at the top are symbols of the healing arts; at the bottom of the insignia is the red, blue, and yellow triangle associated with Armored units, a reference to medical support provided at the largest permanent Armored Post in the United States. “Care And Concern” is the organization’s motto.