metam sodium metam sodium metam sodium is an organosulfur compound with the formula ch3nhcs2na. the compound is a sodium salt of a dithiocarbamate. the compound exists as a colorless dihydrate, but most commonly it is encountered as an aqueous solution. it is used as a soil fumigant, pesticide, herbicide, and fungicide. it is one of the most widely used pesticides in the united states, with approximately 60 million pounds used in 2001. metam sodium names preferred iupac name sodium methylcarbamodithioate other names metham sodiumcarbathioncarbathionecarbothionmetamsodiummetam-sodium identifiers cas number 137-42-8 y 3d model (jsmol) interactive image chemspider 2273119 y echa infocard 100.004.812 pubchem cid 5366415 unii 3cd7ukn224 y comptox dashboard (epa) dtxsid2029167 inchi inchi=1s/c2h5ns2.na/c1-3-2(4)5;/h1h3,(h2,3,4,5);/q;+1/p-1 ykey: afccddwkhlhpdf-uhfffaoysa-m y smiles .c(=s)nc properties chemical formula c2h4nnas2 molar mass 129.18 g/mol except where otherwise noted, data are given for materials in their standard state (at 25 °c , 100 kpa). y verify (what is yn ?) infobox references preparation and properties metam sodium is prepared by combining methylamine, carbon disulfide, and sodium hydroxide: ch3nh2 + cs2 + naoh → ch3nhcs2na + h2o it also arises from the reaction of methyl isothiocyanate and sodium thiolate. upon exposure to the environment, metam sodium decomposes to methyl isothiocyanate. safety and environmental considerations metam sodium is nonpersistent in the environment since it is prone to hydrolysis. the degradation products, carbon disulfide and methyl amine are however toxic. in 1991 a tank car with 19,000 gallons of metam sodium spilled into sacramento river above lake shasta. this killed all fish in a 41-mile stretch of the river. by 20 years later the rainbow trout population had recovered.