Abstract Because of the exothermicity of reaction and the necessity of using active initiators for the vinyl chloride monomer (VCM) suspension polymerization reaction, a study was undertaken in order to choose the best polymerization inhibitor for emergency situations such as temperature runaway, power failures, and agitation system problems. The effect of triethylene glycol‐bis3(3 terc‐butyl‐4‐hydroxy‐5‐methyl phenyl) propionate (1) and N‐nitrosophenylhydroxylamine ammonium salt (2) cited in the literature as free radical polymerization inhibitors on VCM suspension polymerization reactions is shown.