The Harmonized Tariff Schedule of the United States (HTS) was enacted by Congress and made effective on January 1, 1989, replacing the former Tariff Schedules of the United States.
The HTS comprises a hierarchical structure for describing all goods in trade for duty, quota, and statistical purposes. This structure is based upon the international Harmonized Commodity Description and Coding System (HS), administered by the World Customs Organization in Brussels ; the 4- and 6-digit HS product categories are subdivided into 8-digit unique U.S. rate lines and 10-digit non-legal statistical reporting categories. Classification of goods in this system must be done in accordance with the General and Additional U.S. Rules of Interpretation, starting at the 4-digit heading level to find the most specific provision and then moving to the subordinate categories.
The "general" rates of duty subcolumn contains U.S. normal trade relations duty rates; products of some NTR countries may be eligible for preferential tariff programs, as reflected in the "special" subcolumn. Column 2 (the so-called "statutory rates") applies to countries listed in general note 3(b); the general notes set forth the rules for applying the HTS. Embargoes, anti-dumping duties, countervailing duties, and other very specific matters administered by the Executive Branch are not contained in the HTS.
The USITC maintains and publishes the HTS (in print and on-line) pursuant to the Omnibus Trade and Competitiveness Act of 1988; see the preface to the HTS for additional explanatory material. However, the Bureau of Customs and Border Protection of the Department of Homeland Security is responsible for interpreting and enforcing the HTS.