Aqueous solutions of sodium and calcium polysulfides convert labeled simazine, 2-chloro-4,6-bis(ethylamino)-s-triazine-2,4,6-C14, to a chloroform insoluble, charcoal adsorbable derivative which is thought to be hydroxysimazine, 2-hydroxy-4,6-bis(ethylamino)-s-triazine-2,4,6-C14. In soil, calcium polysulfide accelerates the breakdown of simazine as shown by oat bioassay. These results suggest the possibility of using polysulfides to remove unwanted residues of chlorotriazine herbicides from crop lands.