The OECD Guidelines for the Testing of Chemicals, key tools for governments and industry worldwide to assess the safety of chemical products, are now available free of charge on the OECD public website at http://www.oecd.org/env/testguidelines. The Test Guidelines are central to the Mutual Acceptance of Data (MAD), OECD’s long established system for protecting human health and the environment from hazardous chemicals. 116 Test Guidelines have been adopted by OECD since 1981 and are used worldwide. In English and French.