NFPA 704

NFPA 704 exists because of a specific, documented disaster. In 1959, firefighters responding to a blaze at the Charlotte Chemical Company in North Carolina believed they were fighting an ordinary kerosene fire; the storage vat also contained metallic sodium, and their attempt to suppress the fire caused it to explode, critically injuring thirteen firefighters. Fire marshal J.F. Morris of the Charlotte Fire Department subsequently developed the color-coded hazard diamond system that became NFPA 704, aiming to give responders instant, standardized visual warning of a material's hazards before they commit to a firefighting tactic that could be fatal.

The National Fire Protection Association tentatively adopted the system as a guide in 1960 and formally adopted it shortly after, with revisions issued periodically in the decades since. Critically, NFPA 704 is designed for first responders making split-second decisions during an emergency, not for chemists or safety officers -- it deliberately trades the depth of a full Safety Data Sheet for a rating that can be read and understood in seconds from a distance.