A hazmat suit (hazardous materials suit) is a piece of personal protective equipment that consists of an impermeable whole-body garment worn as protection against hazardous materials. Such suits are often combined with self-contained breathing apparatus (SCBA) to ensure a supply of breathable air. Hazmat suits are used by firefighters, emergency medical technicians, paramedics, researchers, personnel responding to toxic spills, specialists cleaning up contaminated facilities, and workers in toxic environments. History The hazmat suit is believed to originate from the Manchurian plague epidemic of 1910–1911, wherein Dr. Wu Lien-teh's promoted the use of various forms of personal protective equipment to prevent the spread of the pneumonic plague. Capabilities Overview The United States Department of Homeland Security defines a hazmat suit as "an overall garment worn to protect people from hazardous materials or substances, including chemicals, biological agents, or radioactive materials." More generally, hazmat suits may provide protection from: Chemical agents through the use of appropriate barrier materials like teflon, heavy PVC or rubber and Tyvek Nuclear agents possibly through radiation shielding in the lining, but more importantly by preventing direct contact with or inhalation of radioactive particles or gas Biological agents through fully sealed systems—often at overpressure to prevent contamination even if the suit is damaged or using powered air purifying respirators with full hoods and protective suits to prevent exposure (level C protection level) Fire/high temperatures usually by a combination of insulating and reflective materials which reduce the effects (see also Fire proximity suit) The hazmat suit generally includes breathing air supplies to provide clean, uncontaminated air for the wearer. In laboratory use, clean air may be supplied through attached hoses. This air is usually pumped into the suit at positive pressure with respect to the surroundings as an additional protective measure against the introduction of dangerous agents into a potentially ruptured or leaking suit. Working in a hazmat suit is very strenuous, as the suits tend to be less flexible than conventional work garments. With the exception of laboratory versions, hazmat suits can be hot and poorly ventilated (if at all). Therefore, use is usually limited to short durations of up to 2 hours, depending on the difficulty of the work. Level A (United States) suits, for example, are limited by their air supply to around 15–20 minutes of very strenuous work (such as a firefighting rescue in a building). However, OSHA/EPA protective level A suits/ensembles are not typically