Harmonized Tariff Classification is based upon the guidance from the World Customs Organization

(WCO) for 180 countries representing more than 98 per cent of all international trade. Goods are

classified using a 6-digit portion that is harmonized across all members plus a variable number of

additional digits that are country-specific. Chemicals are classified in a variety of chapter headings,

but are found primarily in Chapters 28 and 29.