CS₂, a compound used to manufacture products such as rayon and cellophane. Carbon disulfide is produced naturally by microbial activity in marshes and in volcanic ash. Since carbon disulfide does not adhere well to sediments, if it comes into contact with soil, it could percolate into groundwater, where it is very soluble. CS₂ can also add to photochemical smog development when it reacts with other organic substances in the atmosphere, such as methane or oxides of nitrogen.