The use of personal protective equipment (PPE) is inherent in the theory of universal precaution, which requires specialized clothing or equipment for the protection of individuals from hazard. The term is defined by the Occupational Safety and Health Administration (OSHA), which is responsible for PPE regulation, as the "equipment that protects employees from serious injury or illness resulting from contact with chemical, radiological, physical, electrical, mechanical, or other hazards." While there are common forms of PPEs such as gloves, eye shields, and respirators, the standard set in the OSHA definition indicates a wide coverage. This means that PPE involves a sizable range of equipment. There are several ways to classify them such as how gears could be physiological or environmental