The 155th Chemical Battalion Distinctive Unit Insignia was approved on 11 December 2006. It consists of two components: an equilateral and equiangular hexagon that serves as a shield, and a scroll at the bottom emblazoned with the unit motto, “The Fog Of War.” The hexagon is also called a benzene ring and is taken from the branch insignia of the Chemical Corps. The three-headed dragon is a representation of the mythical Hydra; dragons frequently appear in Chemical Corps insignia as symbols of the destruction a unit’s weaponry can wreak. Three stars stand for three campaigns the Battalion’s ancestor unit took part in during World War II.
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.
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For the first three-and-a-half decades of its service life, the 155th Chemical Battalion was assigned to the Infantry branch, originally organized and Federally recognized in the Ohio National Guard as Company B, 147th Infantry on 1 December 1924. It was designated as an element of the 37th Division, a relation that would last until it was redesignated as a non-Infantry unit (HQ and HQ Detachment, 112rh Transportation Battalion) on 1 September 1959. While assigned to the 37th Infantry Division during World War II, the organization took part in three campaigns in the Asiatic-Pacific Theater during World War II: Guadalcanal; Northern Solomons; and Air Offensive, Japan).
The organization would remain a Transportation unit for exactly thirty-seven years: Its consolidation with the 324th Military Police Company came on 1 September 1996, with the newly formed unit retaining the 324th MP Company designation. The 324th MP Company was called into Federal service from February 2003 to November 2004 and took part in two campaigns in the Iraqi Theater in the War on Terrorism, the Transition of Iraq and Iraqi Governance. In 2005—once again on the first day of September—it was expanded, reorganized, and redesignated to create both the Headquarters and Headquarters Detachment, 155th Chemical Battalion and 324th Military Police Company, with the latter beginning a separate lineage at that point.
As of Autumn 2023 the 155th Chemical Battalion was assigned to the 73rd Troop Command, Ohio Army National Guard. In addition to its HQ and HQ Detachment, the Battalion consists of the 173rd Chemical Detachment, 637th Chemical Company, and two Medical Companies (684th and 285th).