A drum's shipping description reads: 'UN2922, Corrosive liquids, toxic, n.o.s., 8 (6.1), PG I.' Based on this description, which labels should be affixed to the drum?

49 CFR 172.402 (subsidiary hazard labels); 49 CFR 172.101 Hazardous Materials Table (UN2922 entry, label codes '8, 6.1')

Subsidiary labels exist because many real-world chemicals are dangerous in more than one way at once — corrosive and toxic, flammable and toxic, and so on. A first responder who sees only one label may approach with the wrong protective equipment, so recognizing the full 'class (subsidiary)' notation is a frequently tested, real-world safety skill.