European Chemicals Agency (ECHA) for information on the classification and labelling requirements for substances on the market in the European Union
The US National Institute for Occupational Safety and Health (NIOSH) have extensive information on hazardous substances including:
GESTIS – A series of very useful databases from the Institute for Occupational Safety and Health of the German Social Accident Insurance (IFA)
International Chemical Safety Cards (ICSCs) from the International Labour Organisation (ILO)
WISER – A database from the US National Library of Medicine designed to assist emergency responders in hazardous material incidents. WISER provides a wide range of information on hazardous substances, including substance identification support, physical characteristics, human health information, and containment and suppression advice.
US Agency for Toxic Substances and Disease Registry – Toxic Substances Portal Although the ATSDR are concerned primarily with environmental health, they have extensive information on the toxic effects of a large number of hazardous substances
IARC Monographs – comprehensive documents summarising the evidence and rationale for the classification of carcinogens by the International Agency for Research on cancer
Pubmed – a bibliographical database from the US National Library of Medicine that contains 30 million citations for biomedical literature from MEDLINE, life science journals, and online books.