system that alerts people at a glance that there are hazardous chemicals present. The symbols help identify whether the chemicals that are going to be in use may potentially cause physical harm, or harm to the environment. The symbols are distinctive, as they are shaped like diamonds with red borders. These signs can be divided into: Explosive (exploding bomb) Flammable (flame) Oxidizing (flame above a circle) Corrosive (corrosion of table and hand) Acute toxicity (skull and crossbones) Hazardous to environment (dead tree and fish) Health hazard/hazardous to the ozone layer (exclamation mark) Serious health hazard (cross on a human silhouette) Gas under pressure (gas cylinder) These pictographs are also subdivided into class and categories for each classification. The assignments for each chemical depends on their type and their severity. Controlling chemical Exposure Elimination and Substitution Chemical exposure is estimated to have caused approximately 190,000 illnesses and 50,000 deaths of workers annually. There exists an unknown link between chemical exposure and subsequent illness and/or death. Therefore, the majority of these illnesses and deaths are thought to be caused by a lack of knowledge and/or awareness concerning the dangers of chemicals. The best method of controlling chemical exposure within the workplace is through the elimination or the substitution of all chemicals that are thought or known to cause illness and/or death. Engineering Controls Although the elimination and the substitution of the harmful chemicals is the best known method for controlling chemical exposure, there are other methods that can be implemented to diminish exposure. The implementation of engineering controls is an example of another method for controlling chemical exposures. When engineer controls are implemented, there is a physical change made to the work environment that will eliminate or reduce the risk to chemical exposure. An example of engineer controls is the enclosure or isolation of the process that creates the chemical hazard. Administrative and Work Practices Controls If the process that creates the chemical hazard cannot be enclosed or isolated, the next best method is the implementation of administrative and work practices controls. This is the establishment of administrate and work practices that will reduce the amount of time and how often the workers will be exposed to the chemical hazard. An example of administrative and work practices controls is the establishment of work schedules in which workers have rotating job assignments. This will ensure that all workers have limited exposure to chemical