A Battery, 231st Armored Field Artillery Battalion, 6th Armored Division, US Army - France, Normandy, August 1944.

The PWD 9.75 inch Chemical Mortar was "marketed" to the U.S. 7th Army in trials at Benny, France in February 1945. The weapon was developed by the Petroleum Warfare Department and fired incendiary shells of White Phosphorus hence the word 'chemical' in the name. It was earlier trialled on a Valentine chassis. It was mounted on three different M7B1 HMC chassis for testing (not M7 chassis). It was not accepted by the Army as it was deemed unsuitable for service (tank-afv.com).