Chemical Mortar Battalions

A crew of the 83rd Chemical Mortar Battalion fires their M2 4.2" mortar in support of advancing Seventh Army units in the Vosges Mountains, late autumn 1944. (US Army Military History Institute)

At various times, the 100th Infantry Division was supported by elements of three different chemical mortar battalions.

Although originally designed primarily to deliver dense sheafs of poison gas and other chemicals, these units nevertheless possessed tremendous conventional firepower as well. Firing primarily white phosphorus (WP) projectiles to create smoke screens and high explosive (HE) shells for the usual tactical purposes, with 36 4.2” (107mm) mortars to a battalion, chemical mortar battalions packed a punch essentially equal to an entire division artillery brigade’s three 105mm howitzers, albeit at shorter range.

Even a single company of “four deuce” mortars (12 pieces) firing “Willie Peter” or HE could match the firepower of a full battalion of 105s.

The crew of a 2nd Chemical Mortar Battalion M2 4.2" mortar fires in support of advancing elements of the 100th Infantry Division, 6 December 1944. (US Army Military History Institute)

Lieutenant Colonel Bruce Elliott, US Army (Retired), a rare two-war (WWII and Korean War) Chemical Mortar Battalion veteran, has created a world-class website dedicated to the history of these unique units.

Below you will find several links to not only the sections of this superb site that cover, in detail, the chemical mortar battalions that supported the 100th Infantry Division in combat, but to the front page of his section overall.

There is also a nested organization chart depicting the generic organization of a WWII chemical mortar battalion, which was common to all three battalions that supported the 100th. Finally, the M2 4.2" mortar itself is described at the final section.

2d Chemical Mortar Battalion (Supported the 100th Infantry Division 3 - 23 December 1944 and 15 - 22 March 1945)

83rd Chemical Mortar Battalion (Supported the 100th Infantry Division 7 - 26 November 1944 and 31 March - 24 April 1945)

99th Chemical Mortar Battalion (Supported the 100th Infantry Division 2 - 3 December 1944 and 21 - 25 March 1945)

United States Army Chemical Mortar Battalions, by LTC Bruce Elliott, USA (Ret.)

Organization Chart for a Chemical Mortar Battalion, September 1944.

The M2 4.2" (107mm) Mortar