The compound exists as a colorless dihydrate, but most commonly it is encountered as an aqueous solution.

It is one of the most widely used pesticides in the United States, with approximately 60 million pounds used in 2001.

[1] Upon exposure to the environment, metam sodium decomposes to methyl isothiocyanate and other sulfur compounds.

[4] Metam sodium is nonpersistent in the environment since it decomposes rather quickly to toxic methyl isothiocyanate and carbon disulfide.

[4] In 1991 a tank car with 19,000 gallons of a metam sodium based pesticide spilled into Sacramento River above Lake Shasta.