This method of restricting methane production in methanogenic bacteria, by the use of the enzyme and coenzyme inhibitors, works during anaerobic reductive dechlorination. Various compounds such as, but not limited to, red yeast rice, vitamin B10 derivatives, and ethanesulfonates are utilized to disrupt these different enzyme and coenzyme systems responsible for the production of methane. This method affects the competition of the methanogen and halo bacteria for the organic hydrogen donors that are injected in the soil and groundwater system during the remediation process.