Sometimes referred to as mustard gas, the term is technically incorrect: bis(2-chloroethyl)sulfide is a liquid at room temperature.

In the Depretz method, sulfur dichloride is treated with ethylene: In the Levinstein process, disulfur dichloride is used instead:[6][failed verification][7] In the Meyer method, thiodiglycol is produced from chloroethanol and potassium sulfide, and the resulting diol is then treated with phosphorus trichloride:[8][9] In the Meyer–Clarke method, concentrated hydrochloric acid (HCl) is used instead of PCl3: Thionyl chloride and phosgene, the latter of which is also a choking agent, have also been used as chlorinating agents.

These compounds have the added advantage in that if they are used in excess, they remain as impurities in the finished product and can therefore produce additional mechanisms of toxicity.

The idealized combustion of mustard gas in oxygen produces hydrochloric acid and sulfuric acid, in addition to carbon dioxide and water: Bis(2-chloroethyl)sulfide reacts with sodium hydroxide, giving divinyl sulfide: Sodium ethoxide acts similarly.

Upon skin contact or inhalation, bis(2-chloroethyl)sulfide is a nonspecific toxin.