the present invention stands directed at apparatus and methods for the addition of selected amounts of alcohol dehydrogenase adh enzyme inhibitors to existing engine cooling systems to reduce or eliminate coolant toxicity as well as the use of such inhibitors for treatment and safe disposal of toxic coolants removed from engines reference to alcohol dehydrogenase adh enzyme inhibitors means any substance that when mixed with eg and ingested prevents or substantially diminishes the production of the various toxic metabolites that are related to eg poisoning such adh enzyme inhibitor may therefore preferably include polyhydric alcohols alcohols that have two hydroxyl or u2014 oh groups that combine and form blended mixtures with the eg reference to blend mixtures with eg should be understood as a mixture wherein the adh enzyme inhibitor and eg will not phase separate preferred adh enzyme inhibitors herein include propylene glycol pg and or glycerol in addition such adh enzyme inhibitors are also preferably those that have a boiling point above 150 u00b0 c 320 u00b0 f for a given and existing engine cooling system the amount of adh enzyme inhibitor that is preferably introduced may vary the goal however is to transform an existing aqueous based eg based engine cooling system which is toxic.