An emergency procedure that involves taking immediate shelter in a readily accessible location, such as a small room, and sealing it from the outside. The term was originally used for hazardous materials situations such as chemical spills, but has been expanded in use to include active shooter situations. In an NBC situation, people are expected to immediately go indoors, bring all children and animals with them, and to close and lock windows and doors. HVAC should be shut off. (SAME code: SPW)
