The risk of mass exposure to toxic substances has increased steadily during the twentieth century due to the expansion of industry and the deliberate development and use of agents of chemical warfare. Although Hong Kong is considered a relatively safe place, hoax anthrax attacks have occurred since 17 October 2001. People who have been seriously injured by hazardous materials have a greater chance of recovery without complications when appropriate emergency treatments are provided. Recognition and identification of hazardous materials, assessment of the conditions, decontamination, and protection of staff and facilities are important elements in the formulation of a contingency plan. The objective of this article is to outline the efforts of the Hong Kong Hospital Authority in formulating a hospital response to incidents involving hazardous materials.