Registry of Toxic Effects of Chemical Substances, published by NIOSH.

A chemical database available through the National Library of Medicine, Bethesda, Maryland.

RTECS, also known as Registry of Toxic Effects of Chemical Substances, is a database of toxicity information compiled from the open scientific literature that is available for charge. Until 2001 it was maintained by US National Institute for Occupational Safety and Health (NIOSH) and is now maintained by the private company Elsevier MDL.