A toxicology database of over 168,000 chemicals compiled, maintained, and updated by the U.S. National Institute of Occupational Safety and Health (NIOSH). Its goal is to include "all known toxic substances... and the concentrations at which... toxicity is known to occur". The acronym also stands for "Residential Transportation Energy Consumption Survey" by the US Department of Energy, which was discontinued in 1994. It is unlikely that RTECS ever appeared on a Material Safety Data Sheet in this context. Additional Info: RTECS was mandated by the same act that created the U.S. Occupational Health and Safety Administration (OSHA). It was originally called the Toxic Substances List. RTECS data is obtained from the open scientific literature and maintained by NIOSH. Unlike many other government databases, RTECS is only available from vendors (if you dislike this, which you should, consult your congressional representatives). NIOSH has additional info and a vendor list if you would like access to the database. That page is a bit out of date, with several of the vendors having undergone consolidation. We were unable to find any firm that publicly posts its current pricing. MSDS Relevance: RTECS data can be used to help you construct an MSDS. Six types of toxicity data are included in the file. (1) primary irritation; (2) mutagenic effects; (3) reproductive effects; (4) tumorgenic effects; (5) acute toxicity; (6) other multiple dose toxicity, including LD₅₀ and LC₅₀ values. See also: EPCRA