Defining lethal chemicals in industrial facilities

Limited legislating attention has been given to the prevention of releases of small quantities of chemicals. It is known that even small leakages can cause severe consequences to the exposed persons. The different international chemical classification schemes show equivalent categorizations, but do not define nor explain lethal chemicals. The new Global Harmonized System (GHS), which is being implemented in various countries, also does not have a category for lethal chemicals. This article provides an overview of the existing classification schemes for the definition of the toxicity of substances. That overview is used to provide guidance in the identification of lethal chemicals for the design of industrial facilities.It is suggested to define lethal chemicals as those chemicals of which a low-dose, single exposure can have lethal effects. Lethality can be associated with acute toxicity and carcinogenity, whereas other human health hazards cannot cause death through a low-dose, single exposure. Therefore, lethal chemicals should include the strictest category of acute toxicity as described in GHS, and proven carcinogens that cause cancer through a low-dose, single exposure event. Utmost attention should be given to prevent the smallest leakage of these chemicals.