Substance profile
Sodium metabisulphite
Sodium metabisulphite is white hexagonal crystals or powder with an in the presences of traces of water, it develops an odor of sulfur dioxide.
01 · Identification
What Sodium metabisulphite is
Sodium metabisulphite is white hexagonal crystals or powder with an in the presences of traces of water, it develops an odor of sulfur dioxide. Its molecular formula is Na2O5S2 and its molecular weight is 190.11 g/mol. It melts at 150 °C, is soluble in water.
Under the GHS it carries the signal word Danger. It is classed as corrosives.
02 · Identifiers
Sodium metabisulphite identifiers and molecular data
Sodium metabisulphite CAS number and EC number
Sodium metabisulphite molecular formula and molecular weight
03 · GHS classification
Sodium metabisulphite hazard classification
Harmonised classification under CLP Annex VI. This is the legally binding classification in the EU; other jurisdictions may differ.
Sodium metabisulphite pictograms and signal word
Sodium metabisulphite hazard class and category
| Hazard class | Category | From code | Pictogram |
|---|---|---|---|
| Acute toxicity - oral GHS chapter 3.1 | Category 4 | H302 | GHS07 |
| Serious eye damage/eye irritation GHS chapter 3.3 | Category 1 | H318 | GHS05 |
Sodium metabisulphite hazard statements (H-codes)
| Code | Hazard statement |
|---|---|
| H302 | Harmful if swallowed. |
| H318 | Causes serious eye damage. |
Sodium metabisulphite supplemental EU statements (EUH)
| Code | Statement |
|---|---|
| EUH031 | Contact with acids liberates toxic gas. |
This page lists only the codes assigned to Sodium metabisulphite. The full reference lives on the hazard statements hub, the precautionary statements hub and the GHS pictograms hub.
Safety Data Sheet
Getting an SDS for Sodium metabisulphite
A Safety Data Sheet is written for a product, not for a substance: the supplier of the grade you actually buy issues it, so two suppliers of Sodium metabisulphite issue two different sheets. That is why there is no single authoritative SDS for a substance to download — what there is, is the job of collecting the sheets for the products you hold and keeping them current as suppliers revise them.
04 · Precautionary statements
Sodium metabisulphite precautionary statements
CLP Annex VI assigns 8 precautionary statements to Sodium metabisulphite. They are grouped the way a label groups them: what to do before handling, what to do when something has already happened, how to store it and how to dispose of it.
Prevention
What to do before and during handling so the hazard never happens.
Response
What to do once exposure, spillage or fire has already happened.
Reading the notation. … is a blank the supplier fills in — not a truncated sentence.· [square brackets] mark a part printed only when it applies.
05 · Names in the regulation
Sodium metabisulphite name in 23 EU languages
CLP Annex VI Part 3 is published in every language edition of the regulation, and the identification column is written out in each of them. Nothing below is translated by us: each line is the name as that edition prints it. Under Art. 18(2) the substance name from Annex VI is a lawful product identifier, so this is the wording to put on a label going to that market — and where the cell lists several designations, any one of them qualifies.
| Language | Name in CLP Annex VI Part 3 |
|---|---|
| Bulgarian български | натриев метабисулфит |
| Spanish español | Metabisulfito de sodio |
| Czech čeština | pyrosiřičitan sodný |
| Danish dansk | natriummetabisulfit |
| German Deutsch | Dinatriumdisulfit Natrium metabisulfitNatriummetabisulfit |
| Estonian eesti | naatriummetabisulfit |
| Greek ελληνικά | μεταδιθειώδες νάτριο |
| English English | sodium metabisulphite |
| French français | métabisulfite de sodium |
| Croatian hrvatski | natrijev metabisulfit |
| Italian italiano | sodio metabisolfito |
| Latvian latviešu | nātrija metabisulfīts |
| Lithuanian lietuvių | natrio metabisulfitas |
| Hungarian magyar | nátrium-metabiszulfit |
| Maltese Malti | metabisulfit tas-sodju |
| Dutch Nederlands | natriummetabisulfiet |
| Polish polski | disiarczan(IV) disodu |
| Portuguese português | metabissulfito de sódio |
| Romanian română | metabisulfit de sodiu |
| Slovak slovenčina | disiričitan sodný |
| Slovenian slovenščina | natrijev metabisulfit |
| Finnish suomi | natriummetabisulfiitti |
| Swedish svenska | natriummetabisulfit |
All 23 language editions of Annex VI carry this entry. Irish is the twenty-fourth official EU language and has no line here for a different reason: no consolidated CLP text has ever been published in Irish, so there is no Irish edition of Annex VI to quote a name from. Source: consolidated CLP, CELEX 02008R1272, language editions. © European Union, https://eur-lex.europa.eu — only the electronic Official Journal of the European Union is authentic.
06 · Label elements
Sodium metabisulphite GHS label elements
Everything CLP Annex VI fixes for Sodium metabisulphite, laid out the way it appears on a label. The greyed lines are the parts only the supplier can fill in.
Danger
Sodium metabisulphite
- Harmful if swallowed.
- Causes serious eye damage.
- Contact with acids liberates toxic gas.
- Do not eat, drink or smoke when using this product.
- Wear protective gloves/protective clothing/eye protection/face protection/hearing protection/…
- IF SWALLOWED:
- IF IN EYES:
- Immediately call a POISON CENTER/doctor/…
- Call a POISON CENTER/doctor/… if you feel unwell.
- Rinse mouth.
- Remove contact lenses, if present and easy to do. Continue rinsing.
Supplier name, address and telephone number· Product identifier·Nominal quantity
Need this as an actual label? Open Sodium metabisulphite in the GHS label constructor →
07 · Health hazards
Sodium metabisulphite health hazards and exposure limits
Sodium metabisulphite hazard summary
A case of occupational asthma, confirmed by specific inhalation challenge, was reported in which a worker sprinkled dry metabisulfite on potatoes. [Malo JL, Cartier A, Desjardins A. Occupational asthma caused by dry metabisulphite. Thorax 1995 May;50(5); 585-6.] Similar cases have been reported in the wine, laundry, and lobster fishing industries. [Madsen J, Sherson D, Kjoller H, Hansen I, Rasmussen K. Occupational asthma caused by sodium disulphite in Norwegian lobster fishing. Occup Environ Med 2004;61:873-874] Occupational skin sensitization has also been reported; [Sulfite contact allergy. Vena GA, Foti C, Angelini G. Contact Dermatitis 1994 Sep;31(3):172-5] In the presence of water and acid, metabisulfite can generate toxic amounts of SO2. [ATSDR Medical Management] A skin, eye, and respiratory tract irritant; May cause asthma; [ICSC] It can be used as a reducing agent in photography and caused dermatitis in a photographic technician, probably acting as an aggravating irritative factor. [Kanerva, p. 1834] See SULFITES. See Potassium metabisulfite.
Source: Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
Sodium metabisulphite carcinogenicity classification
Evaluation: There is inadequate evidence for the carcinogenicity in humans of sulfur dioxide, sulfites, bisulfites and metabisulfites. There is limited evidence for the carcinogenicity in experimental animals of sulfur dioxide. There is inadequate evidence for the carcinogenicity in experimental animals of sulfites, bisulfites and metabisulfites. Overall evaluation: Sulfur dioxide, sulfites, bisulfites and metabisulfites are not classifiable as to their carcinogenicity to humans (Group 3).
Source: Hazardous Substances Data Bank (HSDB)
An IARC group and a CLP classification answer different questions. IARC judges whether the evidence for cancer in humans is strong enough; CLP Annex VI is the legally binding EU classification. A substance can carry one and not the other.
Sodium metabisulphite occupational exposure limits
| Limit | Value | Source |
|---|---|---|
| PEL | none See Appendix G | The National Institute for Occupational Safety and Health (NIOSH) |
| REL | 5 mg/m³ | Occupational Safety and Health Administration (OSHA) |
| REL | TWA 5 mg/m3 | The National Institute for Occupational Safety and Health (NIOSH) |
| IDLH | N.D. | The National Institute for Occupational Safety and Health (NIOSH) |
These are United States values. The European Union sets its own indicative and binding limits, and the figure that applies at a given workplace is the one in the local regulation — not the one shown here.
08 · Physical and chemical properties
Sodium metabisulphite properties
Every value is shown with the conditions it was measured under and the source it came from. Where sources disagree, all values are listed rather than one being picked — the difference is usually a different form of the substance, not an error.
Sodium metabisulphite boiling point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Boiling point | Decomposes | decomposes | NIOSH |
| Decomposes (NIOSH, 2024) | decomposes | CAMEO | |
| decomposes | decomposes | OSHA |
Sodium metabisulphite melting point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Melting point | 150 °C (302 °F) | above this value | HSDB |
Sodium metabisulphite density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Density | 1.4 g/cm³ | NIOSH | |
| 1.4 g/cm³ | at 25 °C | HSDB |
Sodium metabisulphite solubility
| Property | Value | Conditions | Source |
|---|---|---|---|
| Solubility | Freely soluble in water, glycerol; slightly soluble in alcohol | HSDB | |
| Soluble in ethanol | HSDB | ||
| 66.7 g/100 g water at 25 °C | at 25 °C | HSDB |
Sodium metabisulphite lower explosive limit (LEL)
| Property | Value | Conditions | Source |
|---|---|---|---|
| Lower explosive limit (LEL) | Noncombustible Solid | NIOSH |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
09 · Handling and storage
Sodium metabisulphite storage and handling
Sodium metabisulphite safe storage
Separated from acids, strong oxidants and food and feedstuffs. Well closed.
Source: ILO-WHO International Chemical Safety Cards (ICSCs)
Sodium metabisulphite storage conditions
The bulk material should be stored in a well closed container, protected from light, in a cool, dry place.
Source: Hazardous Substances Data Bank (HSDB)
Sodium metabisulphite incompatible materials
Large scale addition of solid sodium disulfite to an unstirred and too-concentrated solution of sodium nitrite caused a vigorous exothermic reaction.
Source: Hazardous Substances Data Bank (HSDB)
Sodium metabisulphite reactivity
SODIUM METABISULFITE is incompatible with the following: Heat (decomposes) [Note: Slowly oxidized to the sulfate on exposure to air & moisture.] (NIOSH, 2024).
Source: CAMEO Chemicals
Planning storage for a mix of chemicals? Check Sodium metabisulphite in the storage compatibility matrix →
10 · Questions
Sodium metabisulphite — frequently asked questions
What is the CAS number of Sodium metabisulphite?
The CAS number of Sodium metabisulphite is 7681-57-4. Its EC number is 231-673-0.
What is the chemical formula of Sodium metabisulphite?
The molecular formula of Sodium metabisulphite is Na2O5S2 and its molecular weight is 190.11 g/mol.
What does a Sodium metabisulphite label have to show?
Under CLP Annex VI the label for Sodium metabisulphite carries the pictograms Corrosion and Exclamation mark and the signal word is Danger.
Is Sodium metabisulphite flammable?
CLP Annex VI assigns Sodium metabisulphite no flammability hazard class. That is not a statement that it cannot burn: the harmonised list only records the hazards that were assessed for it.
Is Sodium metabisulphite a carcinogen?
CLP Annex VI records no harmonised carcinogenicity classification for Sodium metabisulphite. Annex VI is a list of agreed classifications, not a list of substances found safe, so this is an absence of a classification rather than a clean bill of health.
What is the exposure limit for Sodium metabisulphite?
The US occupational exposure limit reported for Sodium metabisulphite is none See Appendix G (The National Institute for Occupational Safety and Health (NIOSH)). Limits differ by country: the EU sets its own indicative and binding values, and the figure that applies at a given workplace is the one in the local regulation.
What is the boiling point of Sodium metabisulphite?
The boiling point reported for Sodium metabisulphite is Decomposes, decomposes (NIOSH).
What is the melting point of Sodium metabisulphite?
The melting point reported for Sodium metabisulphite is 150 °C (302 °F), above this value (HSDB).
How should Sodium metabisulphite be stored?
The bulk material should be stored in a well closed container, protected from light, in a cool, dry place. (Hazardous Substances Data Bank (HSDB))
Nearby
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