In the U.S. Army, the Chemical Corps is a technical branch of service that now has the responsibility for defense against chemical weapons, including decontamination that could also be useful for biological weapons and some radioactive contamination. Other countries have technical specializations with similar names.
Prior to the ratification of the Chemical Weapons Convention, the Chemical Corps had responsibility for planning for offensive chemical warfare and developing chemical agents, equipment, munitions, and operational procedures. It also was responsible for offensive biological warfare.
The use of large-scale obscuring smoke generators is usually a Chemical Corps (or national equivalent) responsibility; while the output of smoke generators is usually nontoxic, some of the chemicals used to produce it require skilled handling.