HTSUS Chapter 31 on the customs broker exam

Chapter 31 of the Harmonized Tariff Schedule covers Fertilizers. Across the released customs broker exams, 3 questions turn on classifying goods in this chapter. Drawn from 3 released sittings, April 2023 through October 2025. Below: every heading CBP has tested, the official heading text, and each exam question that used it.

3105 — Mineral or chemical fertilizers containing two or three of the fertilizing elements nitrogen, phosphorus and potassium; other fertilizers; goods of this chapter in tablets or similar forms or in packages of a gross weight not exceeding 10 kg

What is the CLASSIFICATION of a vegetable-based fertilizer, composed of 8% potassium and 92% other substances, imported in 10-kilogram containers in granular form?
April 2023 exam, question 23 · tests 3105.10.0000. Full question, answer and citation →
What is the CLASSIFICATION of a chemical-based fertilizer, containing nitrogen, phosphorus, and potassium, imported in twenty (20)-kilogram containers in powder form?
October 2023 exam, question 46 · tests 3105.20.0000. Full question, answer and citation →
Of the four choices below, which is the best CLASSIFICATION of diammonium hydrogenorthophosphate?
October 2025 exam, question 31 · tests 3105.30.0000. Full question, answer and citation →

Practise classifying Chapter 31 the way the exam asks it.

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