Understanding “or” and “nor” in OSHA standards (Flammable Liquids LOI)

Specifically, you asked for clarification on the use of the words “or” and “nor” in the paragraph Design, Construction, and Capacity of Storage Cabinets-Maximum Capacity, 29 CFR 1910.106(d)(3)(i), which states,

1910.106(d)(3)(i) Not more than 60 gallons of Class I or Class II liquids, nor more than 120 gallons of Class III liquids may be stored in a storage cabinet.