Analysis
Heading 3507 of the Harmonized Tariff Schedule covers enzymes; prepared enzymes not elsewhere specified or included. It divides into 2 six-digit subheadings and 3 eight-digit tariff lines, with 4 ten-digit statistical suffixes below them.
Every one of its 3 tariff lines is duty-free at the general rate, so classification within the heading affects statistics and Chapter 99 measures rather than the base duty.
Its median rate of duty-free sits at the 25th percentile of the headings in chapter 35.
The largest subheadings are 3507.90 (other, 2 lines) and 3507.10 (unnamed, 1 line).
By Census's concordance, most of its statistical lines are made by All Other Basic Organic Chemical Manufacturing (325199). Those are the NAICS industries a US producer of these goods would report under.
The heading text decides whether a product belongs here at all (General Rule of Interpretation 1); the subheadings and lines below it only apply once that is settled. Section and chapter notes can override the heading wording, so read them for borderline goods.
Tariff lines
| Line | Description | General rate |
|---|---|---|
| 3507.10.00 | Rennet and concentrates thereof | Free |
| 3507.90.20 | Pencillin G amidase | Free |
| 3507.90.70 | Other: other | Free |