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HSChapter 25
U.S. imports of fused magnesia, dead-burned magnesia & other magnesium oxides (HS 251990) totaled $32.9M in July 2026, traded with 21 countries.
Importers of Fused Magnesia, Dead-Burned Magnesia & Other Magnesium Oxides paid $134K in duties in July 2026 — an effective duty rate of 10% on $1.3M in dutiable value, based on actual customs collections rather than the published tariff schedule. Fused Magnesia, Dead-Burned Magnesia & Other Magnesium Oxides imports of $32.9M in July 2026 ran 50% above the year-to-date monthly average of $21.9M.
Last updated: July 2026 dataThermally processed magnesium oxides — including fused magnesia (2519901000), caustic-calcined magnesite (2519902000), and other magnesium oxides (2519905000) — serve distinct industrial roles ranging from high-temperature refractory bricks to agricultural and environmental applications. China is the dominant supplier across all three product types, and imports from China are subject to Section 301 tariffs, a significant landed-cost consideration for US buyers. Canada, Brazil, Israel, and Mexico supply the balance, with Israel notable for high-purity caustic-calcined grades used in environmental and chemical applications. The processing route — fusion temperature, sintering degree, and resulting crystal density — determines which 10-digit line applies and which end-use markets the product serves.
AI-written summary of the official U.S. Census Bureau trade figures on this page — verify before relying on it.
384 shipments/mo
Fused magnesia (2519901000) is produced by melting magnesite in an electric arc furnace, yielding very high density and purity — used in premium refractory applications. Dead-burned (sintered) magnesia is fired at extremely high temperatures (above 1500°C) to produce a dense, low-reactivity product for furnace linings. Caustic-calcined magnesite (2519902000) is fired at lower temperatures, retaining reactivity for agricultural, environmental, and chemical uses. The supplier's certificate of analysis specifying bulk density, LOI, and production method is essential for correct classification.
Imports of magnesium oxide products from China are subject to Section 301 tariffs. Because rates and product coverage under Section 301 can change, importers should verify the current applicable rate for the specific 10-digit HTS line at the time of entry and factor this into total landed cost calculations. Working with a licensed customs broker is advisable given the complexity of Section 301 exclusion requests and modifications.
Subheading 1 of 2 in heading 2519
Subheading 251990 · $32.9M of $33.0M
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ImportsExports
Imports
$32.9MYoY · Pro
Exports
$3.4MYoY · Pro
12-mo low · imports
YoY · ProThrough July 2026. Source: U.S. Census Bureau.
HS10 import codes under this HS6 parent, each with its own page. Source: U.S. Harmonized Tariff Schedule.
| Code | Description | Import Value | Effective Tariff % | Dutiable Share | Duty Collected |
|---|---|---|---|---|---|
| 2519901000 | Magnesia, Fused and Dead-Burned (Sintered) | $23.5M | 0.00% | 0.00% | -- |
| 2519902000 | Magnesite, Caustic Calcined | $7.5M | 0.00% | 0.00% | -- |
| 2519905000 | Magnesium Oxides, NESOI | $1.9M | 7.13% | 69.88% | $134K |
HS10 export codes under this HS6 parent, each with its own page. Source: U.S. Schedule B export classification.
| Code | Description | Export Value |
|---|---|---|
| 2519901000 | Magnesia, Fused and Dead-Burned (Sintered) | $1.6M |
| 2519905000 | Magnesium Oxides, NESOI | $1.3M |
| 2519902000 | Magnesite, Caustic Calcined | $499K |
Import lines come from the U.S. Harmonized Tariff Schedule and export lines from Schedule B. The two are numbered by different agencies, so the same 10-digit code can appear in both tables describing a different product.
Imports · July 2026
origin
China and Canada together supply 81% of it.
customs district
destination
entry
rate provision · imports
96.0% enters free of duty; the effective duty rate is 0.41%.