Positive pressure personnel suits (PPPS)—or positive pressure protective suits, informally known as "space suits", "moon suits", "blue suits", etc.—are highly specialized, totally encapsulating, industrial protection garments worn only within special biocontainment or maximum containment (BSL-4) laboratory facilities. These facilities research dangerous pathogens which are highly infectious and may have no treatments or vaccines available. These facilities also feature other special equipment and procedures such as airlock entry, quick-drench disinfectant showers, special waste disposal systems, and shower exits.

A biological hazard, or biohazard, is a biological substance that poses a threat to the health of living organisms, primarily humans. This could include a sample of a microorganism, virus or toxin that can adversely affect human health. A biohazard could also be a substance harmful to other living beings.