UN 3291 (Regulated Medical Waste)
The shipping classification trauma scene waste travels under, Division 6.2. It is not UN 3373, which covers biological substances shipped for diagnosis. A company using the wrong number is worth questioning.
What kind of thing this is
UN 3291 (Regulated Medical Waste) is a rule with legal force in this field. This definition comes from a primary government source. Where the wording matters we quote the standard rather than paraphrase it, because paraphrase is where precision leaks out.
Where you will meet it
This one shows up when you ask a company how it operates — in an exposure control plan, on a waste manifest, or in the paragraph of a state statute somebody quotes at you. It binds businesses rather than households, which is the distinction most often blurred when it is cited at a homeowner.
Why the wording matters
This site defines terms in under forty words wherever it can, and attaches the practical consequence rather than leaving it implied. A definition that tells you what something is, without telling you what follows from it, is trivia at a moment when nobody has room for trivia.