Environmental research professionals, occupational health professionals, and safety engineers rely on fast access to data on chemical substances known to be hazardous to human health and the environment. Such factual substance data can be found in Material Safety Data Sheets (MSDS) provided by manufacturers of chemicals, traditional databases such as the Registry of Toxic Effects of Chemical Substances (RTECS) or the Hazardous Chemicals Data Base (HSDB), and with the help of search engines or portals on the free Internet. The questions investigated in this paper are: can the WWW be used as a source for reliable data on chemical compounds? And can particular search services be recommended for particular questions? Recommendations for searching information about chemicals on the Internet are given.