The physical state of the product at the time of importation — not the storage method — governs heading selection. Propane and butane transported under pressure in a liquefied state are classified under the liquefied headings (271112, 271113), while the same hydrocarbons transported in true gaseous form (e.g., in high-pressure cylinders without liquefaction) fall under 271129. In practice, most bulk commercial propane and butane is liquefied for transport, so gaseous-state classification is more common for small-cylinder or specialty industrial gas shipments.

The Dominican Republic's position likely reflects re-export or transshipment activity, where LPG or associated gas products are processed or repackaged before export to the US. Angola's presence reflects associated gas production from its offshore oil fields, where some gas streams are exported in gaseous form or as part of mixed hydrocarbon shipments. The diversity of the supplier list in this NESOI heading is characteristic of residual categories that capture a wide range of product types and trade flows not fitting neatly into the more specific headings.