2nd Chemical Battalion

The 2nd Chemical Battalion was first constituted on 15 August 1917 in the Regular Army as the 30th Engineer Regiment (Gas and Flame) and organized on 30 August-28 November 1917 at Camp American University, Washington, DC. The unit was converted and redesignated on 13 July 1918 as the 1st Gas Regiment. 3rd and 4th Battalions, 1st Gas Regiment were organized on 24 October 1918 at Camp Sherman, Ohio. The 1st Gas Regiment was sent to Europe and participated in 6 campaigns during the Great War: Lys, Aisne-Marne, St. Mihiel, Meuse-Argonne, Flanders 1918, and Lorraine 1918. After the end of the Great War, the 3rd and 4th Battalions, 1st Gas Regiment were demobilized between 15-20 December 1918 at Camp Sherman, Ohio. The rest of the 1st Gas Regiment was demobilized on 28 February 1919 at Camp Kendrick, Lakehurst, New Jersey.

The unit was reconstituted on 24 February 1920 in the Regular Army as the 1st Gas Regiment and organized at Edgewood Arsenal, Maryland. It was redesignated on 5 February 1929 as the 1st Chemical Regiment and inactivated on 15 April 1935 at Edgewood Arsenal, Maryland. The unit was entirely disbanded on 12 March 1942.

The unit was reconstituted again on 7 November 1951 in the Regular Army. It was concurrently consolidated with the active 2nd Chemical Mortar Battalion. That unit had been first constituted on 25 March 1935 in the Regular Army as the 2nd Separate Chemical Battalion and activated on 16 April 1935 (less Companies B, C, and D and Medical Detachment) at Edgewood Arsenal, Maryland. Companies B, C, and D and Medical Detachment were activated on 1 April 1942 at Fort Bragg, North Carolina. The 2nd Separate Chemical Battalion was reorganized and redesignated on 7 September 1943 as the 2nd Chemical Battalion, Motorized and again on 31 December 1944 as the 2nd Chemical Mortar Battalion. Deployed to Europe, the Battalion 7 campaigns: Sicily (awarded streamer with arrowhead for participation in the initial assault), Naples-Foggia (streamer with arrowhead), Rome-Arno, Southern France (streamer with arrowhead), Rhineland, Ardennes-Alsace, and Central Europe. After the Second World War, the unit was inactivated on 26 July 1946 in Germany. It was reaactivated on 1 February 1949 at the Army Chemical Center, Edgewood, Maryland before being consolidated with the 1st Chemical Regiment. The consolidated unit was designated as the 2nd Chemical Mortar Battalion.

The unit was subsequently deployed to Korea where it participated in 8 campaigns of the Korean War: UN Offensive, CCF Intervention, First UN Counteroffensive, CCF Spring Offensive, UN Summer-Fall Offensive, Second Korean Winter, Korea Summer-Fall 1952, and Third Korean Winter. The unit was then reorganized and redesignated on 23 January 1953 as the 2nd Chemical Weapons Battalion.

The Headquarters Company, 2nd Chemical Weapons Battalion was disbanded on 16 January 1955 at Dugway Proving Ground, Utah. Headquarters, 2nd Chemical Weapons Battalion was reorganized and redesignated on 7 January 1958 as Headquarters and Headquarters Detachment, 2nd Chemical Battalion. Companies A, B, and C were concurrently disbanded at Dugway Proving Ground, Utah. Headquarters and Headquarters Detachment, 2nd Chemical Battalion was later inactivated on 19 December 1973, having moved to Fort McClellan, Alabama.

The Headquarters and Headquarters Detachment, 2nd Chemical Battalion was reactivated on 1 September 1981 at Fort Hood, Texas as part of III Corps. The Battalion deployed elements in support of Operations Desert Shield and Desert Storm in 1990-1991. It participated in 3 campaigns in Southwest Asia: Defense of Saudi Arabia, Liberation and Defense of Kuwait, and Cease-Fire.

By the early 2000s, the 2nd Chemical Battalion consisted of a Headquarters and Headquarters Detachment, the 44th Chemical Company, the 46th Chemical Company, and the 181st Chemical Company. Its mission was to, on order, deploy designated theater of operations and provides command and control over chemical units conducting NBC operations in support of US Forces.

In 2007, the 48th Chemical Brigade was activated at Fort Hood, Texas and the 2nd Chemical Battalion subsequently became assigned to the new brigade.