used in firefighting rescue, especially during a building/structure fire. National Fire Protection Association (NFPA) compliant "turnout gear", and NIOSH-certified SCBA, or CBRN SCBA, are the primary protection technologies for structure firefighting in the US. Ratings In the United States Hazmat protective clothing is classified as any of Level A, B, C, or D, based upon the degree of protection they provide. Level A The highest level of protection against vapors, gases, mists, and particles is Level A, which consists of a fully encapsulating chemical entry suit with a full-facepiece self-contained breathing apparatus (SCBA). A person must also wear boots with steel toes and shanks on the outside of the suit and specially selected chemical-resistant gloves for this level of protection. The breathing apparatus is worn inside (encapsulated within) the suit. To qualify as Level A protection, an intrinsically safe two-way radio is also worn inside the suit, often incorporating voice-operated microphones and an earpiece speaker for monitoring the operations channel. Level B Level B protection requires a garment (including SCBA) that provides protection against splashes from a hazardous chemical. Since the breathing apparatus is sometimes worn on the outside of the garment, Level B protection is not vapor-protective. Level B suits can also be fully encapsulating, which helps prevent the SCBA from becoming contaminated. It is worn when vapor-protective clothing (Level A) is not required. Wrists, ankles, facepiece and hood, and waist are secured to prevent any entry of splashed liquid. Depending on the chemical being handled, specific types of gloves and boots are donned. These may or may not be attached to the garment. The garment itself may be one piece or a two-piece hooded suit. Level B protection also requires the wearing of chemical-resistant boots with steel toes and shanks on the outside of the garment. As with Level A, chemical-resistant gloves and two-way radio communications are also required. Level C Level C protection differs from Level B in the area of equipment needed for respiratory protection. The same type of garment used for Level B protection is worn for Level C. Level C protection allows for the use of respiratory protection equipment other than SCBA. This protection includes any of the various types of air-purifying respirators. People should not use this level of protection unless the specific hazardous material is known and its concentration can be measured. Level C equipment does not offer the protection needed in