Industrial Hygiene is the science of environmental exposure assessment. Industrial Hygienists (IHs) are professionals dedicated to the health and well-being of people, keeping them safe from exposure to hazardous chemicals, biological microorganisms and radiation of all types. Certified Industrial Hygienists (CIH) are those that have reached the highest level of certification available in the field of industrial hygiene and environmental testing.  Originally industrial hygienists worked primarily in factories and other industrial settings but as our society has changed, so has the definition of industrial hygiene. Today, IHs can be found in almost every type of work or environmental setting. Some IHs, including EHSI, perform outside the workplace by consulting in residential situations and environmental (e.g., hazardous waste site) projects.