Class III biological safety cabinets, also known as gloveboxes or barrier isolators, are ideal for working with any biosafety level 4 agents, or other dangerous materials such as aerosols of pathogens or toxins. With two high-efficiency particulate air (HEPA) filters at the exhaust point, a class III biological safety cabinet protects the user and the environment from the specimen under study. A HEPA filter at the air supply also protects the specimen within the glovebox. Manipulations within the hermetically-sealed chamber of a class III biological safety cabinet are performed using built-in arm-length rubber gloves. Because the glovebox is airtight, the specimen must be introduced through a dunk tank, or through an adjacent double-door chamber that can be decontaminated. Class III biological safety cabinets with carbon filtration systems are also available for working with hazardous chemicals.