Abstract: A high efficiency process for removal and detoxification of olefin oxides from gas compositions is described. The process consists of olefin oxide absorption at ambient pressure in an absorber using an aqueous liquid as the absorbing medium and subsequent hydrolysis of the olefin oxide to products including an alkylene glycol in a chemical reactor operating at a controlled temperature and pH in the presence of an acid catalyst. The absorption stage is favored by low temperature and high liquid to gas ratios. More than 99% of an olefin oxide contained in a gas stream can be effectively removed in the absorption stage. The hydrolysis stage is favored by low pH conditions. More than 99% of the incoming olefin oxide to the reactor can be converted to alkylene glycols. The process has a capability of removing and detoxifying olefin oxide from gas streams with an overall effectiveness exceeding 98%. The process also provides for recovering inert diluent contained in the gas compositions.