Substance profile
Sulfuric acid
Sulfuric acid is colorless, oily liquid and is odorless.
01 · Identification
What Sulfuric acid is
Sulfuric acid is colorless, oily liquid and is odorless. Its molecular formula is H2O4S and its molecular weight is 98.08 g/mol. It boils at 337 °C, melts at 10.3 °C, is miscible with water.
Under the GHS it carries the signal word Danger. It is classed as carcinogens.
02 · Identifiers
Sulfuric acid identifiers and molecular data
Sulfuric acid CAS number and EC number
Sulfuric acid molecular formula and molecular weight
Other names for Sulfuric acid
- battery acid
- oil of vitriol
- H2SO4
- Bov
- Chamber Acid
- Contact Acid
- Dihydrogen Sulfate
- Dipping Acid
- Fertilizer Acid
- Hydrogen Sulfate
- Matting Acid
- Nordhausen Acid
- Spent Sulfuric Acid
- Spirit Of Sulfur
- Sulfuric Acid (Aerosol Forms Only)
- sulphuric acid ... %
03 · GHS classification
Sulfuric acid hazard classification
Harmonised classification under CLP Annex VI. This is the legally binding classification in the EU; other jurisdictions may differ.
Sulfuric acid pictograms and signal word
Sulfuric acid hazard class and category
| Hazard class | Category | From code | Pictogram |
|---|---|---|---|
| Skin corrosion/irritation GHS chapter 3.2 | Category 1A or 1B or 1C | H314 | GHS05 |
Where two values are shown with “or”, the hazard statement is shared by more than one category or by more than one class, and the code alone does not say which. H272, for example, belongs to oxidising liquids and to oxidising solids — the physical state decides. The binding answer for a specific entry is in the CLP Annex VI table itself.
Sulfuric acid hazard statements (H-codes)
| Code | Hazard statement |
|---|---|
| H314 | Causes severe skin burns and eye damage. |
This page lists only the codes assigned to Sulfuric acid. 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 Sulfuric acid
Our own Sulfuric acid safety data sheet walks through all sixteen sections of the published data. What it is not is the document an inspector asks for: an SDS is issued for a product by its supplier, so the sheet covering the grade actually standing in your store exists only in that supplier’s version. Collecting those and keeping them current as suppliers revise them is a separate job.
04 · Precautionary statements
Sulfuric acid precautionary statements
CLP Annex VI assigns 5 precautionary statements to Sulfuric acid. 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
Sulfuric acid 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 | сярна киселина … % |
| Spanish español | Ácido sulfúrico al … % |
| Czech čeština | kyselina sírová … % |
| Danish dansk | svovlsyre … % |
| German Deutsch | Schwefelsäure … % |
| Estonian eesti | väävelhape … % |
| Greek ελληνικά | θειικό οξύ … % |
| English English | sulphuric acid … % |
| French français | acide sulfurique à … % |
| Croatian hrvatski | sumporna kiselina … % |
| Italian italiano | acido solforico …% |
| Latvian latviešu | sērskābe … % |
| Lithuanian lietuvių | …% sieros rūgštis |
| Hungarian magyar | kénsav … % |
| Maltese Malti | aċidu sulfuriku … % |
| Dutch Nederlands | zwavelzuur … % |
| Polish polski | kwas siarkowy(VI) … % |
| Portuguese português | ácido sulfúrico a ... % |
| Romanian română | acid sulfuric ... % |
| Slovak slovenčina | kyselina sírová ... % |
| Slovenian slovenščina | žveplova kislina ... % |
| Finnish suomi | rikkihappo… % |
| Swedish svenska | svavelsyra % |
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
Sulfuric acid GHS label elements
Everything CLP Annex VI fixes for Sulfuric acid, laid out the way it appears on a label. The greyed lines are the parts only the supplier can fill in.
Danger
Sulfuric acid
- Causes severe skin burns and eye damage.
- Do not breathe dust/fume/gas/mist/vapours/spray.
- Wear protective gloves/protective clothing/eye protection/face protection/hearing protection/…
- IF SWALLOWED:
- Immediately call a POISON CENTER/doctor/…
- Do NOT induce vomiting.
Supplier name, address and telephone number· Product identifier·Nominal quantity
Need this as an actual label? Open Sulfuric acid in the GHS label constructor →
07 · Health hazards
Sulfuric acid health hazards and exposure limits
Sulfuric acid hazard summary
77%-98% acid causes second or third degree burns after short contact; [CHRIS] Solutions <30% are corrosive; solutions >30% are highly corrosive; [Quick CPC] Human carcinogen designation refers to sulfuric acid contained in strong inorganic acid mists. A corrosive substance that can cause pulmonary edema; [ICSC] May cause erosion of teeth enamel; [HSDB] See Strong inorganic acid mists.
Source: Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
Sulfuric acid carcinogenicity classification
Evaluation: There is sufficient evidence that occupational exposure to strong-inorganic-acid mists containing sulfuric acid is carcinogenic. Overall evaluation: Occupational exposure to strong-inorganic-acid mists is carcinogenic to humans (Group 1).
Source: Hazardous Substances Data Bank (HSDB)
Strong inorganic acid mists containing sulfuric acid are known to be human carcinogens based on sufficient evidence of carcinogenicity from studies in humans.
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.
Sulfuric acid occupational exposure limits
| Limit | Value | Source |
|---|---|---|
| PEL | 1.0 [mg/m3] | Haz-Map, Information on Hazardous Chemicals and Occupational Diseases |
| PEL | 1 mg/m³ | Occupational Safety and Health Administration (OSHA) |
| PEL | TWA 1 mg/m3 | The National Institute for Occupational Safety and Health (NIOSH) |
| REL | 1 mg/m³ | Occupational Safety and Health Administration (OSHA) |
| REL | TWA 1 mg/m3 | The National Institute for Occupational Safety and Health (NIOSH) |
| IDLH | 15 mg/m3 (NIOSH, 2024) | CAMEO Chemicals |
| IDLH | 15 mg/m3 [From NPG: Sulfuric acid] (NIOSH, 2024) | CAMEO Chemicals |
| IDLH | 15.0 [mg/m3] | Haz-Map, Information on Hazardous Chemicals and Occupational Diseases |
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
Sulfuric acid 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.
Sulfuric acid boiling point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Boiling point | 337 °C (638.6 °F) | HSDB | |
| 290 °C (554 °F) | NIOSH | ||
| 290 °C (554 °F) | at 760 mmHg | CAMEO |
Sulfuric acid melting point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Melting point | 10.31 °C (50.6 °F) | HSDB | |
| 10.56 °C (51 °F) | NIOSH | ||
| 10.36 °C (50.6 °F) | CAMEO |
Sulfuric acid density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Density | 1.8302 g/cm³ | HSDB | |
| 1.84 g/cm³ | NIOSH | ||
| 1.841 g/cm³ | CAMEO |
Sulfuric acid solubility
| Property | Value | Conditions | Source |
|---|---|---|---|
| Solubility | Miscible with water and alcohol with the generation of much heat and with contraction in volume. | HSDB | |
| Miscible | NIOSH | ||
| Miscible (NIOSH, 2024) | CAMEO |
Sulfuric acid vapor pressure
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor pressure | 0.001 mmHg | NIOSH | |
| 0.0000593 mmHg | at 25 °C | HSDB |
Sulfuric acid autoignition temperature
| Property | Value | Conditions | Source |
|---|---|---|---|
| Autoignition temperature | Not flammable (USCG, 1999) | CAMEO |
Sulfuric acid lower explosive limit (LEL)
| Property | Value | Conditions | Source |
|---|---|---|---|
| Lower explosive limit (LEL) | Risk of fire and explosion on contact with base(s), combustible substances, oxidants, reducing agents or water. | HSDB | |
| Noncombustible Liquid, but capable of igniting finely divided combustible materials. | NIOSH |
Sulfuric acid vapor density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor density | 3.4 (air = 1) | HSDB |
Sulfuric acid odor threshold
| Property | Value | Conditions | Source |
|---|---|---|---|
| Odor threshold | Threshold for odor= 1.0 mg/cu m, Irritating concn= 1.1 mg/cu m | HSDB | |
| Odor Threshold Low: 0.15 [mg/m3] | Haz-Map | ||
| Odor threshold from AIHA | Haz-Map |
Sulfuric acid critical temperature and pressure
| Property | Value | Conditions | Source |
|---|---|---|---|
| Critical temperature and pressure | 655 °C (1211 °F) | HSDB |
Sulfuric acid corrosivity
| Property | Value | Conditions | Source |
|---|---|---|---|
| Corrosivity | Strongly corrosive | HSDB | |
| Concentrated acid is non-corrosive to lead and mild steel but dilute acid attacks most metals | HSDB | ||
| Corrosion data for ASTM Grade 2 Titanium: Boiling sulfuric acid at a concentration of 1% by weight had a corrosion rate of 2.5 mm/yr. | HSDB |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
09 · Fire and explosion
Sulfuric acid fire and explosion behaviour
These are descriptions rather than measured values, so they are kept out of the table above and quoted here with the source that reported them.
Sulfuric acid fire potential
Not combustible. Strong dehydrating agent, which may cause ignition of finely divided materials on contact. Reaction with metals may produce hydrogen gas. Oxides of sulfur may be produced in fire.
Source: Hazardous Substances Data Bank (HSDB)
10 · Handling and storage
Sulfuric acid storage and handling
Sulfuric acid reactive group
CAMEO Chemicals places Sulfuric acid in the reactive group Acids, Strong Oxidizing. Compatibility with other chemicals is worked out from the group, not from the individual substance — which is why two substances you have never seen react can still be flagged as a pair that must be separated.
A reactive group is a CAMEO Chemicals (US NOAA) grouping, not a GHS hazard class: it has no code, no category and no legal force. It is what the storage compatibility matrix on this site computes from.
Sulfuric acid safe storage
Dry. Separated from food and feedstuffs and incompatible materials. See Chemical Dangers. Store only in original packaging.
Source: ILO-WHO International Chemical Safety Cards (ICSCs)
Sulfuric acid storage conditions
Keep container tightly closed in a dry and well-ventilated place. Containers which are opened must be carefully resealed and kept upright to prevent leakage.
Source: Hazardous Substances Data Bank (HSDB)
Sulfuric acid incompatible materials
Incompatible materials: Bases, halides, organic materials, carbides, fulminates, nitrates, picrates, cyanides, chlorates, alkali halides, zinc salts, permanganates, e.g. potassium permanganate, hydrogen peroxide, azides, perchlorates, nitromethane, phosphorous; Reacts violently with: cyclopentadiene, cyclopentanone oxime, nitroaryl amines, hexalithium disilicide, phosphorous(iii) oxide, powdered metals.
Source: Hazardous Substances Data Bank (HSDB)
Sulfuric acid reactivity
SULFURIC ACID, SPENT is diluted and partly neutralized sulfuric acid recovered from industrial use. Likely to contain multiple impurities. Reacts an an acid and as a weak oxidizing agent. Chars wood and most other organic matter, but is unlikely to cause a fire. Zinc iodide reacts violently with H2SO4. (Pascal, 1962, Vol. 5, 168).
Source: CAMEO Chemicals
Planning storage for a mix of chemicals? Check Sulfuric acid in the storage compatibility matrix →
11 · Transport
Sulfuric acid UN number and transport classification
Transport classification is a separate system from the GHS classification above. It decides how a package is marked and how a load may be carried; it does not follow from the workplace label, and the workplace label does not follow from it. The entries below are linked by CAS number, never by name.
The same CAS number is shipped under more than one UN number. Which entry applies follows from the form and the concentration of the consignment — read the proper shipping name, not the CAS.
Sulfuric acid under UN 1830 — shipping name, class and packing group
Europe · ADR 2025, Table A
| Proper shipping name (3.1.2) | Class | Classification code | PG | Labels (column 5) |
|---|---|---|---|---|
| SULPHURIC ACID with more than 51 % acid | 8 | C1 | II | |
Source: ADR 2025, Table A of Chapter 3.2 · ECE/TRANS/352 Vol. I (UNECE). Class 8 is “Corrosive substances” (ADR 2.1.1.1).
United States · 49 CFR 172.101 Hazardous Materials Table
| Proper shipping name (column 2) | Class or division | PG | Labels (column 6) |
|---|---|---|---|
| Sulfuric acid with more than 51 percent acid | 8 | II | |
Source: 49 CFR 172.101 Hazardous Materials Table · eCFR, revision 2026-08-03. Class 8 is “Corrosive material” (49 CFR 173.2).
Sulfuric acid under UN 1831 — shipping name, class and packing group
Europe · ADR 2025, Table A
| Proper shipping name (3.1.2) | Class | Classification code | PG | Labels (column 5) |
|---|---|---|---|---|
| SULPHURIC ACID, FUMING | 8 | CT1 | I | |
Source: ADR 2025, Table A of Chapter 3.2 · ECE/TRANS/352 Vol. I (UNECE). Class 8 is “Corrosive substances” (ADR 2.1.1.1).
United States · 49 CFR 172.101 Hazardous Materials Table
| Proper shipping name (column 2) | Class or division | PG | Labels (column 6) |
|---|---|---|---|
| Sulfuric acid, fuming with less than 30 percent free sulfur trioxide | 8 | I | |
| Sulfuric acid, fuming with 30 percent or more free sulfur trioxide | 8 | I | |
Source: 49 CFR 172.101 Hazardous Materials Table · eCFR, revision 2026-08-03. Class 8 is “Corrosive material” (49 CFR 173.2).
Sulfuric acid under UN 1832 — shipping name, class and packing group
Europe · ADR 2025, Table A
| Proper shipping name (3.1.2) | Class | Classification code | PG | Labels (column 5) |
|---|---|---|---|---|
| SULPHURIC ACID, SPENT | 8 | C1 | II | |
Source: ADR 2025, Table A of Chapter 3.2 · ECE/TRANS/352 Vol. I (UNECE). Class 8 is “Corrosive substances” (ADR 2.1.1.1).
United States · 49 CFR 172.101 Hazardous Materials Table
| Proper shipping name (column 2) | Class or division | PG | Labels (column 6) |
|---|---|---|---|
| Sulfuric acid, spent | 8 | II | |
Source: 49 CFR 172.101 Hazardous Materials Table · eCFR, revision 2026-08-03. Class 8 is “Corrosive material” (49 CFR 173.2).
Sulfuric acid under UN 2796 — shipping name, class and packing group
Europe · ADR 2025, Table A
| Proper shipping name (3.1.2) | Class | Classification code | PG | Labels (column 5) |
|---|---|---|---|---|
| SULPHURIC ACID with not more than 51 % acid or BATTERY FLUID, ACID | 8 | C1 | II | |
Source: ADR 2025, Table A of Chapter 3.2 · ECE/TRANS/352 Vol. I (UNECE). Class 8 is “Corrosive substances” (ADR 2.1.1.1).
United States · 49 CFR 172.101 Hazardous Materials Table
| Proper shipping name (column 2) | Class or division | PG | Labels (column 6) |
|---|---|---|---|
| Battery fluid, acid | 8 | II | |
| Sulfuric acid with not more than 51% acid | 8 | II | |
Source: 49 CFR 172.101 Hazardous Materials Table · eCFR, revision 2026-08-03. Class 8 is “Corrosive material” (49 CFR 173.2).
12 · Questions
Sulfuric acid — frequently asked questions
What is the CAS number of Sulfuric acid?
The CAS number of Sulfuric acid is 7664-93-9. Its EC number is 231-639-5.
What is the chemical formula of Sulfuric acid?
The molecular formula of Sulfuric acid is H2O4S and its molecular weight is 98.08 g/mol.
What does a Sulfuric acid label have to show?
Under CLP Annex VI the label for Sulfuric acid carries the pictogram Corrosion and the signal word is Danger.
Is Sulfuric acid flammable?
CLP Annex VI assigns Sulfuric acid 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 Sulfuric acid a carcinogen?
CLP Annex VI records no harmonised carcinogenicity classification for Sulfuric acid. 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 Sulfuric acid?
The US occupational exposure limit reported for Sulfuric acid is 1.0 [mg/m3] (Haz-Map, Information on Hazardous Chemicals and Occupational Diseases). 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 Sulfuric acid?
The boiling point reported for Sulfuric acid is 337 °C (638.6 °F) (HSDB).
What is the melting point of Sulfuric acid?
The melting point reported for Sulfuric acid is 10.31 °C (50.6 °F) (HSDB).
How should Sulfuric acid be stored?
Keep container tightly closed in a dry and well-ventilated place. Containers which are opened must be carefully resealed and kept upright to prevent leakage. (Hazardous Substances Data Bank (HSDB))
Nearby
Substances next to Sulfuric acid
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