Standard International Trade Classification
U.S. imports of Limestone Flux and Calcareous Stone for Lime or Cement Manufacture (SITC 27322) totaled $2.8M in August 2026, imported from 10 countries.
Importers of Limestone Flux and Calcareous Stone for Lime or Cement Manufacture paid $35K in duties in August 2026, an average duty rate of 1.26% — duty actually collected as a share of the imports that cleared customs, not the published tariff schedule. Limestone Flux and 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 calcareous stone destined for lime or cement production are bulk industrial minerals that serve as the foundational raw material for the construction materials supply chain. The heading captures material specifically characterized by its end-use suitability — high calcium carbonate content and appropriate reactivity for kiln processing — rather than by a particular physical form. Steel producers also use limestone flux as a slag-forming agent in blast furnace operations, making this heading relevant to both the construction and metals industries. Importers should be prepared to document the intended industrial use, as the same calcareous stone in a different form or end-use may be classified under a different heading.
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99 import shipments a month
Both uses — steelmaking flux and cement/lime production feedstock — are captured within this heading when the material is calcareous stone in a form suitable for those industrial processes. The heading does not restrict to a single end-use. However, if the limestone has been calcined (burned to produce quicklime or hydrated lime), it would be classified under a different heading covering processed lime products.
Cement-grade limestone is typically specified by CaCO₃ content (generally above 90%), silica and clay impurity levels, and particle size distribution after crushing. Importers supplying cement plants should obtain a full chemical analysis certificate from the quarry, as off-spec material can disrupt kiln chemistry and may be rejected at the plant even if it clears customs without issue.
Basic heading 104 of 239 in section 2
Basic heading 27322 · $2.8M of $3.8B
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Imports · August 2026
origin
Canada and Dominican Republic together supply 99% of it. Dominican Republic pays 12.5% duty; Canada 0.0%.
customs district
Census does not publish district detail for this classification system.
destination
Census does not publish state detail for this classification system.
entry
Census does not publish port detail for this classification system.
ImportsExports
Imports
$2.8MYoY · free account
Exports
$1.2MYoY · free account
12-mo low · imports
Low · free accountOver the twelve months to August 2026, the U.S. imported $18.5M of Limestone Flux and Calcareous Stone for Lime or Cement Manufacture and exported $16.6M.
Through August 2026. Source: U.S. Census Bureau.