Analysis
HTS 2519.90.20 covers caustic calcined magnesite under heading 2519 (natural magnesium carbonate (magnesite); fused magnesia; dead-burned (sintered) magnesia…).
The normal trade relations rate here is zero, shared by about 91% of the 78 tariff lines in chapter 25, a useful check when a neighbouring dutiable line is a candidate. Free here means free of the base duty only: origin-specific Chapter 99 duties such as Section 301 can still be owed.
The other lines in the same group are 2519.90.10 (fused magnesia and dead-burned (sintered) magnesia, duty-free) and 2519.90.50 (other: other, duty-free).
Census statistics map these goods to NAICS 327992 (Ground or Treated Mineral and Earth Manufacturing), an industry of 275 US establishments employing 10,279 people. That concordance is how imports of this line are compared with US output.
All 2 neighbouring lines carry the same duty-free rate, so a borderline choice between them changes the statistics reported, not the duty paid.
Every edition we compared, from Jan 2023 to Oct 2026 (Rev. 22), shows the same general rate of Free.
Neighbouring lines
| Line | Description | General rate |
|---|---|---|
| 2519.90.10 | Fused magnesia and dead-burned (sintered) magnesia | Free |
| 2519.90.50 | Other: other | Free |