South Korea’s Ministry of Environment (MoE) officially publishes the first priority existing chemicals (PEC) list totaling 510 substances on 1 July 2015. Hydrates existing in the 510 substances shall be classified as PEC substances. For manufacturers/importers of substances in the list, they shall perform the registration obligation within three years if manufacturing/importing amount exceeds 1 tonne/year, otherwise such manufacturing and importing will be deemed as illegal and relevant parties will be punished under the Act on the Registration and Evaluation of Chemicals (K-REACH). Enterprises may still manufacture or import such products within the three-year transitional period. After the transitional period, all substances in PEC list shall make registration before their manufacture/import and use.