Surveillance is an important activity that yields a body of information and provides data that can be used to make informed decisions and direct training, education and outreach. The New York State Hazardous Substances Emergency Events Surveillance (HSEES) program is one of 14 state-based programs funded by the US Centers for Disease Control and Prevention that collects data on acute releases of non-petroleum hazardous substances and their public health impacts. New York State HSEES data for 2000-2006 include 7735 hazardous substances releases and the resulting public health consequences. Through daily monitoring of hazardous substances incidents, staff identifies sentinel events and discerns atypical patterns. Staff also alerts public health officials and others, as necessary, to help ensure that the appropriate network of personnel is notified. The New York State HSEES data provide information for employee and responder training, emergency preparedness and public health response. Throughout these activities, staff works to support hazardous materials response, promote safety, protect public health, and work with communities and schools to achieve the HSEES goal of reducing the incidence of hazardous material releases and the associated morbidity and mortality. These outcomes exhibit the value of surveillance of hazardous substances releases. (C) 2008 Elsevier Ltd. All rights reserved.