Measures to Cope with By-product Hexachlorobenzene under the Chemical Substances Control Law

March 17, 2006

Recently, it was revealed that Hexachlorobenzene (HCB) is generated as a by-product during the process of synthesizing Tetrachlorophtalic anhydride (TCPA, CAS No.117-08-8), and is contained not only in TCPA but also in its derivatives (e.g. Solvent Red 135, CAS No.20749-68-2). To cope with this unintentional contaminant HCB, the Ministry of Health, Labour and Welfare (MHLW), the Ministry of Economy, Trade and Industry (METI) and the Ministry of the Environment (MOE) decided to establish an "Assessment Committee on the BAT* Levels for Reduction of a Specified Chemical as a Contaminant By-product" to evaluate the technically and economically best feasible level (BAT level) for reduction of HCB. In addition, the three Ministries required manufactures and importers of TCPA and Solvent Red 135 to take their best measures to reduce the contaminant HCB in these products as well as to manage and report the status of their production, import, sales and storage.

HCB is to be eliminated globally based on the Stockholm Convention** and is designated in Japan as one of the Class 1 Specified Chemicals of which production, import and use are prohibited under the Chemical Substances Control Law. According to a survey conducted by the three Ministries concerning the usage of TCPA and Solvent Red 135, there would be no risk of affecting human health through the use of their final products (e.g. plastics colored by the Solvent Red 135), judging from the estimated level and condition of HCB contained in such products. However, since it is important to reduce the contaminant HCB, the Class 1 Specified Chemical, as a by-product in other chemical substances as much as possible, the Law requires its reduction by applying the BAT for preventing its generation.