Using a blowtorch, Sgt. William W. Patnode, Headquarters Battalion, Chemical Biological Radiological Nuclear chief, activates o-Chlorobenzylidene Malononitrile gas, more commonly known as CS gas, during a Field Protective Mask Confidence Exercise using the newly issued M50 Joint Service General Purpose gas masks at the base gas chamber Dec. 2. - Using a blowtorch, Sgt. William W. Patnode, Headquarters Battalion, Chemical Biological Radiological Nuclear chief, activates o-Chlorobenzylidene Malononitrile gas, more commonly known as CS gas, during a Field Protective Mask Confidence Exercise using the newly issued M50 Joint Service General Purpose gas masks at the base gas chamber Dec. 2.