# HS code 3824.91: Mixtures and preparations consisting mainly of (5-ethyl-2-methyl-2-oxido-1,3,2-dioxaphosphinan-5-yl)methyl methyl methylphosphonate and bis[(5-ethyl-2-methyl-2-oxido-1,3,2-dioxaphosphinan-5-yl)methyl] methylphosphonate

> HS code 3824.91 covers mixtures and preparations consisting mainly of (5-ethyl-2-methyl-2-oxido-1,3,2-dioxaphosphinan-5-yl)methyl methyl methylphosphonate and bis[(5-ethyl-2-methyl-2-oxido-1,3,2-dioxaphosphinan-5-yl)methyl] methylphosphonate, other than those classified in 3824.92 and 3824.99. It sits in heading 38.24 (prepared binders for foundry moulds or cores; chemical products and preparations of the chemical or allied industries (including those consisting of mixtures of natural products), not elsewhere specified or included) in chapter 38 (miscellaneous chemical products). Other goods of heading 38.24 are classified under 3824.10 (prepared binders for foundry moulds or cores), 3824.30 (non-agglomerated metal carbides mixed together or with metallic binders), 3824.40 (prepared additives for cements, mortars or concretes), 3824.50 (non-refractory mortars or concretes) and 12 others.

Source: https://staging.border.bot/hs-codes/382491
Last updated: 13 October 2026

[HS codes](https://staging.border.bot/hs-codes) / [Chapter 38](https://staging.border.bot/hs-codes/38) / [38.24](https://staging.border.bot/hs-codes/3824) / [3824.91](https://staging.border.bot/hs-codes/382491)

## Key facts

- HS code: 3824.91
- Covers: Mixtures and preparations consisting mainly of (5-ethyl-2-methyl-2-oxido-1,3,2-dioxaphosphinan-5-yl)methyl methyl methylphosphonate and bis[(5-ethyl-2-methyl-2-oxido-1,3,2-dioxaphosphinan-5-yl)methyl] methylphosphonate
- Heading: [38.24: Prepared binders for foundry moulds or cores; chemical products and preparations of the chemical or allied industries (including those consisting of mixtures of natural products), not elsewhere specified or included](https://staging.border.bot/hs-codes/3824)
- Chapter: [38: Miscellaneous chemical products](https://staging.border.bot/hs-codes/38)
- Edition: HS2022
- Duty rates: [Set by each country’s tariff](https://staging.border.bot/countries)

## What this code covers

HS code 3824.91 covers mixtures and preparations consisting mainly of (5-ethyl-2-methyl-2-oxido-1,3,2-dioxaphosphinan-5-yl)methyl methyl methylphosphonate and bis[(5-ethyl-2-methyl-2-oxido-1,3,2-dioxaphosphinan-5-yl)methyl] methylphosphonate, other than those classified in 3824.92 and 3824.99.

The legal text of the subheading is “Other: Mixtures and preparations consisting mainly of (5-ethyl-2-methyl-2-oxido-1,3,2-dioxaphosphinan-5-yl)methyl methyl methylphosphonate and bis[(5-ethyl-2-methyl-2-oxido-1,3,2-dioxaphosphinan-5-yl)methyl] methylphosphonate”, read under “Other”, in HS2022.

## What it doesn’t cover

Other goods of heading 38.24 are classified under 3824.10 (prepared binders for foundry moulds or cores), 3824.30 (non-agglomerated metal carbides mixed together or with metallic binders), 3824.40 (prepared additives for cements, mortars or concretes), 3824.50 (non-refractory mortars or concretes) and 12 others.

- [3824.10](https://staging.border.bot/hs-codes/382410) Prepared binders for foundry moulds or cores
- [3824.30](https://staging.border.bot/hs-codes/382430) Non-agglomerated metal carbides mixed together or with metallic binders
- [3824.40](https://staging.border.bot/hs-codes/382440) Prepared additives for cements, mortars or concretes
- [3824.50](https://staging.border.bot/hs-codes/382450) Non-refractory mortars and concretes
- [3824.60](https://staging.border.bot/hs-codes/382460) Sorbitol other than that of subheading 2905.44
- [3824.81](https://staging.border.bot/hs-codes/382481) Goods specified in subheading note 3 to this chapter: Containing oxirane (ethylene oxide)
- [3824.82](https://staging.border.bot/hs-codes/382482) Goods specified in subheading note 3 to this chapter: Containing polychlorinated biphenyls (PCBs), polychlorinated terphenyls (PCTs) or polybrominated biphenyls (PBBs)
- [3824.83](https://staging.border.bot/hs-codes/382483) Goods specified in subheading note 3 to this chapter: Containing tris(2,3-dibromopropyl) phosphate
- [3824.84](https://staging.border.bot/hs-codes/382484) Goods specified in subheading note 3 to this chapter: Containing aldrin (ISO), camphechlor (ISO) (toxaphene), chlordane (ISO), chlordecone (ISO), DDT (ISO) (clofenotane (INN), 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane), dieldrin (ISO, INN), endosulfan (ISO), endrin (ISO), heptachlor (ISO) or mirex (ISO)
- [3824.85](https://staging.border.bot/hs-codes/382485) Goods specified in subheading note 3 to this chapter: Containing 1,2,3,4,5,6-hexachlorocyclohexane (HCH (ISO)), including lindane (ISO, INN)
- [3824.86](https://staging.border.bot/hs-codes/382486) Goods specified in subheading note 3 to this chapter: Containing pentachlorobenzene (ISO) or hexachlorobenzene (ISO)
- [3824.87](https://staging.border.bot/hs-codes/382487) Goods specified in subheading note 3 to this chapter: Containing perfluorooctane sulphonic acid, its salts, perfluorooctane sulphonamides, or perfluorooctane sulphonyl fluoride
- [3824.88](https://staging.border.bot/hs-codes/382488) Goods specified in subheading note 3 to this chapter: Containing tetra-, penta-, hexa-, hepta- or octabromodiphenyl ethers
- [3824.89](https://staging.border.bot/hs-codes/382489) Goods specified in subheading note 3 to this chapter: Containing short-chain chlorinated paraffins
- [3824.92](https://staging.border.bot/hs-codes/382492) Other: Polyglycol esters of methylphosphonic acid
- [3824.99](https://staging.border.bot/hs-codes/382499) Other: Other

## How it is structured

3824.91 is a six-digit subheading. Its first two digits, 38, are the chapter; the first four, 3824, are heading 38.24; the last two, 91, identify the subheading within the heading.

Countries add their own digits after these six for their national tariff lines.

- Chapter 38: Miscellaneous chemical products
- Heading 38.24: Prepared binders for foundry moulds or cores; chemical products and preparations of the chemical or allied industries (including those consisting of mixtures of natural products), not elsewhere specified or included
- Within the heading: Other
- Subheading 3824.91: Mixtures and preparations consisting mainly of (5-ethyl-2-methyl-2-oxido-1,3,2-dioxaphosphinan-5-yl)methyl methyl methylphosphonate and bis[(5-ethyl-2-methyl-2-oxido-1,3,2-dioxaphosphinan-5-yl)methyl] methylphosphonate

## In other countries

No national tariff lines under 3824.91 are live on border.bot yet. Tariffs built on the Harmonized System (HS2022) use 3824.91 at six digits and add their own digits after it.

- Previous subheading: [3824.89](https://staging.border.bot/hs-codes/382489) Goods specified in subheading note 3 to this chapter: Containing short-chain chlorinated paraffins
- Next subheading: [3824.92](https://staging.border.bot/hs-codes/382492) Other: Polyglycol esters of methylphosphonic acid

## Frequently asked questions

### What does HS code 3824.91 cover?

HS code 3824.91 covers mixtures and preparations consisting mainly of (5-ethyl-2-methyl-2-oxido-1,3,2-dioxaphosphinan-5-yl)methyl methyl methylphosphonate and bis[(5-ethyl-2-methyl-2-oxido-1,3,2-dioxaphosphinan-5-yl)methyl] methylphosphonate, other than those classified in 3824.92 and 3824.99.

### Which heading and chapter is HS code 3824.91 in?

HS code 3824.91 is in heading 38.24 (prepared binders for foundry moulds or cores; chemical products and preparations of the chemical or allied industries (including those consisting of mixtures of natural products), not elsewhere specified or included) in chapter 38 (miscellaneous chemical products).

### Where are goods of heading 38.24 classified when 3824.91 doesn’t fit?

Other goods of heading 38.24 are classified under 3824.10 (prepared binders for foundry moulds or cores), 3824.30 (non-agglomerated metal carbides mixed together or with metallic binders), 3824.40 (prepared additives for cements, mortars or concretes), 3824.50 (non-refractory mortars or concretes) and 12 others.

## Sources and updates

The Harmonized System legal text comes from border.bot release 1 (edition HS 2022), imported from a file, and has been live since 13 October 2026.

This page was last updated on 13 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.

Machine-readable: https://staging.border.bot/hs-codes/382491.json