Mustard gas was first invented in 1822 by César-Mansuète Despretz. However, it was not until 1860 that the compound was properly synthesized and studied through the experiments of British scientist Frederick Guthrie. His experiments yielded a proper characterization of the compound as well as notes regarding its irritating properties.
In 1886, Viktor Meyer of Germany created a mustard gas compound that had a higher purity. This compound was made using a combination of aqueous potassium sulfide and 2-chloroethanol. The resulting compound was further treated using phosphorus trichloride and thiodiglycol. This amplified the effects of the compound, causing the irritation to appear hours after exposure. The effects of Meyer's higher purity compound also took longer to recover form compared to earlier forms of mustard gas.