# United States tariff line 2521.00.00.00: Limestone flux; limestone and other calcareous stone, of a kind used for the manufacture of lime or cement

> In the United States tariff, line 2521.00.00.00 covers limestone flux; limestone and other calcareous stone, of a kind used for the manufacture of lime or cement. Goods under this line enter free of general (MFN) duty. It falls under HS subheading 2521.00 in heading 25.21 (chapter 25).

Source: https://border.bot/countries/united-states/hs-codes/2521000000
Last updated: 9 October 2026

[Countries](https://border.bot/countries) / [United States](https://border.bot/countries/united-states) / [Chapter 25](https://border.bot/countries/united-states/hs-codes/25) / [2521.00](https://border.bot/countries/united-states/hs-codes/252100) / [2521.00.00.00](https://border.bot/countries/united-states/hs-codes/2521000000)

## Key facts

- Tariff line: 2521.00.00.00
- Covers: Limestone flux; limestone and other calcareous stone, of a kind used for the manufacture of lime or cement
- Duty (MFN): Free
- Additional duties: None recorded
- Restrictions: None recorded
- Tariff: [United States](https://border.bot/countries/united-states)
- HS subheading: [2521.00](https://border.bot/hs-codes/252100)

## What this line covers

In the United States tariff, line 2521.00.00.00 covers limestone flux; limestone and other calcareous stone, of a kind used for the manufacture of lime or cement.

Its legal text is “Limestone flux; limestone and other calcareous stone, of a kind used for the manufacture of lime or cement”.

## How it is structured

It falls under HS subheading 2521.00 in heading 25.21 (chapter 25). The first six digits are the Harmonized System code; the 4 digits after them are added by the United States tariff.

- Chapter 25: Salt; sulphur; earths and stone; plastering materials, lime and cement
- Heading 25.21: Limestone flux; limestone and other calcareous stone, of a kind used for the manufacture of lime or cement

## Duty

Goods under this line enter free of general (MFN) duty.

## In other countries

No other national tariff on border.bot has live lines under 2521.00 yet.

- [The Harmonized System text for 2521.00](https://border.bot/hs-codes/252100)

- Previous line: [2520.20.00.00](https://border.bot/countries/united-states/hs-codes/2520200000) Plasters
- Next line: [2522.10.00.00](https://border.bot/countries/united-states/hs-codes/2522100000) Quicklime

## Frequently asked questions

### What does tariff line 2521.00.00.00 cover in the United States tariff?

In the United States tariff, line 2521.00.00.00 covers limestone flux; limestone and other calcareous stone, of a kind used for the manufacture of lime or cement.

### What is the general (MFN) duty on 2521.00.00.00 in the United States?

Goods under this line enter free of general (MFN) duty.

## Sources and updates

The tariff lines for the United States come from border.bot release 1 (edition 2026HTSRev21), read from the publisher’s files, and have been live since 9 October 2026.

The duty rates for the United States come from border.bot release 1 (edition 2026HTSRev21), read from the publisher’s files, and have been live since 9 October 2026.

The trade programmes for the United States come from border.bot release 1 (edition 2026HTSRev21), read from the publisher’s files, and have been live since 9 October 2026.

This page was last updated on 9 October 2026.

Guidance from published tariff data, not a binding ruling. For a decision customs must follow, apply to the destination’s customs authority for a binding tariff ruling.

Official source files:

- https://hts.usitc.gov/reststop/exportList?from=0000000000&to=9999999999&format=CSV&styles=false

Machine-readable: https://border.bot/countries/united-states/hs-codes/2521000000.json