Harmonized System
U.S. imports of limestone flux & other calcareous stone for lime or cement manufacture (HS 252100) totaled $2.8M in August 2026, imported from 10 countries.
Importers of Limestone Flux & Other Calcareous Stone for Lime or Cement Manufacture paid $35K in duties in August 2026, an effective tariff rate of 1.26% of the $2.8M imported — duty actually collected as a share of that value, not the published tariff schedule. Limestone Flux & Other Calcareous Stone for Lime or Cement Manufacture imports of $2.8M in August 2026 ran 102% above the year-to-date monthly average of $1.4M.
Last updated: August 2026 dataLimestone flux and other calcareous stones used in the manufacture of lime and cement are bulk industrial minerals classified under tariff line 2521000000, serving as essential inputs for steelmaking, water treatment, and construction materials production. Canada is the primary US supplier, with Dominican Republic and Jamaica also significant sources — the Caribbean origins reflecting the region's abundant high-purity limestone deposits and cost-effective bulk maritime shipping to US Gulf and East Coast ports. The calcium carbonate content and physical form (lump versus crushed) are the principal specifications that determine suitability for metallurgical flux versus cement kiln feed applications.
AI-written summary of the official U.S. Census Bureau trade figures on this page — verify before relying on it.
99 shipments/mo
The classification of limestone under 2521000000 is specifically for material used or intended for use in the manufacture of lime or cement, or as a metallurgical flux. Crushed limestone used as road aggregate or fill material is classified under heading 2517. The declared end use and the physical and chemical specifications of the material — particularly CaCO₃ purity and particle size — are the key factors customs authorities examine to determine the correct heading.
Both Jamaica and the Dominican Republic have large, high-purity limestone deposits that are geologically well-suited for flux and cement applications. Their island locations enable cost-effective bulk vessel loading directly to US Gulf and East Coast ports, often at lower freight costs than overland shipment from inland North American quarries. This maritime logistics advantage makes them competitive despite the absence of a land border with the US.
HSChapter 25
Subheading 1 of 1 in heading 2521
Subheading 252100 · $2.8M of $2.8M
Trade Directory
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ImportsExports
Imports
$2.8MYoY · free account
Exports
$1.2MYoY · free account
12-mo low · imports
YoY · free accountOver the twelve months to August 2026, the U.S. imported $18.5M of Limestone Flux & Other Calcareous Stone for Lime or Cement Manufacture.
Through August 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 |
|---|---|---|---|---|---|
| 2521000000 | Limestone Flux; Limestone & Other Calcareous Stone | $2.8M | 1.26% | 10.10% | $35K |
HS10 export codes under this HS6 parent, each with its own page. Source: U.S. Schedule B export classification.
| Code | Description | Export Value |
|---|---|---|
| 2521000000 | Limestone Flux; Limestone & Other Calcareous Stone | $1.2M |
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 · August 2026
origin
Canada and Dominican Republic together supply 99% of it. Dominican Republic pays 12.5% duty; Canada 0.0%.
customs district
destination
entry
rate provision · imports
89.9% enters free of duty; duty collected equals 1.26% of total import value.