The military taxonomy of class indices for chemical and biological warfare agents considers halogenated tear agents (CS) to be incapacitating causing local pain and discomfort with associated reflexe. The removal yield of the organic substances present in the water depends on the environmental conditions, on the chemical composition of the water and on the chemical substance dissolved in the water, which constitutes the substrate of the metabolic activities of the microorganisms that use these substances in the biochemical reactions of the cellular enzyme complexes. The two -CN groups in the malonic nitrile molecule are strongly electron-attracting and activate the CH2 group to which they are linked, and because of this, malononitrile has the role of a methylene component in condensation reactions with aldehydes or ketones. The results obtained after analyzing the degree of hydrolysis in the samples that contained the biological suspension indicated that no CBM metabolites were detected in any biological sample, regardless of the test concentration, analyzed 24 h after incubation. In the parallel samples, the aqueous solutions of CBM without biological treatment had metabolites in the samples., at 30 minutes the degree of hydrolysis is 0.21%, at 60 minutes, the degree of hydrolysis is 5.42%, after 90 minutes, the degree of hydrolysis is 6.19%, and after 24 hours. the degree of hydrolysis is 23.41%. Chemical substances in contact with microorganisms are used by them in the biochemical processes in which they are involved, the retention time and biodegradation capacity have led to an increased effect of the metabolism of toxic substances, in metabolic reactions, organic substances are the source of carbon and energy for biochemical processes. The tests performed indicate that the suspension of Chlorella sp. consumed the entire amount of CBM and metabolites from the analyzed samples The tests prove that the biological material can be used for the decontamination of the affected areas.