CAS 7681-57-4

Sodium metabisulfite

焦亚硫酸钠

Na2S2O5MW 190.11 g/molHS 283210

From the buying desk

Food grade and technical grade are both widely exported, often at 97% minimum as Na2S2O5. It releases sulfur dioxide on contact with acids and moisture, so store it dry and away from acids. Not dangerous goods by sea, but it causes serious eye damage and needs sealed bags.

Import Card

Before you order sodium metabisulfite from China, see its register listing, the duty, anti dumping cases and a supplier check on one card, each with its source and date.

Card for the US Card for Australia

Identifiers

Synonyms
Sodium pyrosulfite, Disodium disulfite, SMBS
Formula
Na2S2O5
Molecular weight
190.11 g/mol
SMILES
[O-]S(=O)S(=O)(=O)[O-].[Na+].[Na+]
InChIKey
HRZFUMHJMZEROT-UHFFFAOYSA-L
HS code (6-digit)
283210

Transport and hazard profile

GHS hazard statements, Danger. H-codes, H302, H318. Refer to the substance SDS Section 2 for the full classification.

US and Australian rules for Sodium metabisulfite

Read from the official lists by CAS 7681-57-4. Screening only: check the source before you ship, store or report.

California Prop 65

No entry

No entry for CAS 7681-57-4 in the OEHHA list dated July 31, 2026.

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OSHA exposure limit

No entry

No entry for CAS 7681-57-4 in 29 CFR 1910.1000 Tables Z-1 to Z-3.

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Australian exposure standard

Listed

5 mg/m³ as an 8 hour average.

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CERCLA reportable quantity

No entry

No entry for CAS 7681-57-4 in 40 CFR 302.4 as read on September 24, 2026.

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EPCRA Tier II threshold

No entry

Not on the Extremely Hazardous Substances list, so the general 10,000 lb Tier II threshold applies where an SDS is required.

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Common applications

  • · Food and wine preservative
  • · Water treatment dechlorination
  • · Mining flotation
  • · Photographic and textile bleaching

Sourcing documentation chain

Every shipment of Sodium metabisulfite from China should include a per-batch COA, a current SDS per GB/T 17519 on the China side and the destination jurisdiction's standard on the import side, a packing list, a bill of lading, and a certificate of origin. For Incoterms reference see FOB, CIF, and CFR.

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