The aqueous ozonation of atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] at pH 6 afforded four primary products: 6-amino-2-chloro-4-(isopropylamino)-s-triazine, 6-amino-2-chloro-4(ethylamino)-s-triazine, 4-acetamido-2-chloro-6-(ethylamino)-s-triazine, and 4-acetamido-2-chloro-6(isopropylamino)-s-triazine. These compounds were subsequently degraded to 2-chloro-4,6-diacetamido-s-triazine, 4-acetamido-6-amino-2-chloro-s-triazine, and 2-chloro-4,6-diamino-s-triazine. The amino alkyl groups are the first site of attack and are either removed or converted to the acetamide but not to the aldehyde. The s-triazine ring remains intact, and the chlorine is not removed. Studies also demonstrated that the alkyl group is far more reactive than the amide moiety, which in turn is oxidized more rapidly than the amino group.