Classification · CBLE study guide
Classification: chemicals & plastics (Ch. 25-40)
- 27past questions in CBLE Pass
- ≈1questions on a typical 80-question exam
- HTSUS Sections V-VIIwhere the rules live
Common traps
Wrong answers on past exams cluster around a few beliefs. Here is each one, and what the rule actually says.
Chemicals named in Ch. 31
“Pure DAP is an inorganic chemical or a single-nutrient fertilizer.”
The rule: Ch. 31 Note 5 places diammonium hydrogenorthophosphate in heading 3105 even when pure.
Remember: DAP → 3105.30.
HTSUS Ch. 31 Note 5 · HTSUS 3105.30
Pesticides put up for retail sale
“A pesticide chemical stays in Ch. 29 even when packaged for retail.”
The rule: Fungicides and similar products put up in forms or packings for retail sale, or as preparations, go in 3808 (fungicides 3808.92), not in the chemical's Ch. 29 heading.
Remember: Retail or mixed pesticide → 3808.
HTSUS 3808.92 · HTSUS Ch. 29, Note 2
Reclosable plastic bags
“Food bags are insulated bags or paper bags.”
The rule: Polyethylene sacks and bags go in 3923.21; reclosable bags split by size and slider.
Remember: PE bag → 3923.21.
HTSUS 3923.21
Fertilizers in small packages
“Fertilizer goes by content regardless of packaging.”
The rule: Goods of Ch. 31 in tablets or packages of 10 kg gross or less go in 3105.10; larger NPK fertilizers → 3105.20.
Remember: ≤10 kg package → 3105.10.
HTSUS 3105.10 · HTSUS 3105.20
Medicaments with toxins
“Botulinum toxin injections are cosmetics or albumins.”
The rule: Toxins are covered by heading 3002; a therapeutic injection of botulinum toxin classifies in 3002, not 3304 (cosmetics) or 3502 (albumins).
Remember: Toxins → 3002.
HTSUS 3002 · Ch. 35 Note 1
Salt
“Iodized salt is a seasoning or an iodine compound.”
The rule: Heading 2501 covers salt, including table salt, whether or not containing added anti-caking or iodizing agents.
Remember: Salt stays salt.
HTSUS 2501
Try a past question
October 2026 CBLE, question 34
Of the four choices below, which heading should be used to classify diammonium hydrogenorthophosphate, which contains 18% nitrogen and 46% phosphorus?
Show the answer and why
A. Incorrect. 2805 covers alkali metals; diammonium phosphate is placed in 3105 by Ch. 31 Note 5.
B. Incorrect. 3102 is nitrogenous fertilizers.
C. Incorrect. 3104 is potassic fertilizers.
D. Correct. Ch. 31 Note 5 places diammonium phosphate in 3105.
HTSUS Ch. 31 Note 5 · law as of 2026-11-09
Practice this topic
CBLE Pass has all 27 past questions on classification: chemicals & plastics (ch. 25-40) with an explanation for every option, plus timed mock exams and drills on your weakest topics.
Open the app