Substance profile
Iodine
Iodine is bluish-black scales or plates; diatomic; violet vapor with a sharp characteristic odor.
01 · Identification
What Iodine is
Iodine is bluish-black scales or plates; diatomic; violet vapor with a sharp characteristic odor. It boils at 184 °C, melts at 114 °C.
Under the GHS it carries the signal word Warning.
02 · Identifiers
Iodine identifiers and molecular data
Iodine CAS number and EC number
03 · GHS classification
Iodine hazard classification
Harmonised classification under CLP Annex VI. This is the legally binding classification in the EU; other jurisdictions may differ.
Iodine pictograms and signal word
Iodine hazard class and category
| Hazard class | Category | From code | Pictogram |
|---|---|---|---|
| Acute toxicity - dermal GHS chapter 3.1 | Category 4 | H312 | GHS07 |
| Acute toxicity - inhalation GHS chapter 3.1 | Category 4 | H332 | GHS07 |
| Hazardous to the aquatic environment - acute GHS chapter 4.1 | Category 1 | H400 | GHS09 |
Iodine hazard statements (H-codes)
| Code | Hazard statement |
|---|---|
| H332 | Harmful if inhaled. |
| H312 | Harmful in contact with skin. |
| H400 | Very toxic to aquatic life. |
This page lists only the codes assigned to Iodine. 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 Iodine
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 Iodine 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
Iodine precautionary statements
CLP Annex VI assigns 10 precautionary statements to Iodine. 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.
Disposal
What has to happen to the contents and the empty container.
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
Iodine 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 | йод |
| Spanish español | Yodo |
| Czech čeština | jod |
| Danish dansk | iod |
| German Deutsch | Iod |
| Estonian eesti | jood |
| Greek ελληνικά | ιώδιο |
| English English | iodine |
| French français | iode |
| Croatian hrvatski | jod |
| Italian italiano | iodio |
| Latvian latviešu | jodīns |
| Lithuanian lietuvių | jodas |
| Hungarian magyar | jód |
| Maltese Malti | jodju |
| Dutch Nederlands | jood |
| Polish polski | jod |
| Portuguese português | iodo |
| Romanian română | iod |
| Slovak slovenčina | jód |
| Slovenian slovenščina | jod |
| Finnish suomi | jodi |
| Swedish svenska | jod |
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
Iodine GHS label elements
Everything CLP Annex VI fixes for Iodine, laid out the way it appears on a label. The greyed lines are the parts only the supplier can fill in.
Warning
Iodine
- Harmful if inhaled.
- Harmful in contact with skin.
- Very toxic to aquatic life.
- Do not breathe dust/fume/gas/mist/vapours/spray.
- Use only outdoors or in a well-ventilated area.
- Avoid release to the environment.
- Wear protective gloves/protective clothing/eye protection/face protection/hearing protection/…
- IF ON SKIN:
- IF INHALED:
- Call a POISON CENTER/doctor/… if you feel unwell.
- Wash with plenty of water/…
- Collect spillage.
- Dispose of contents/container to …
Supplier name, address and telephone number· Product identifier·Nominal quantity
Need this as an actual label? Open Iodine in the GHS label constructor →
07 · Health hazards
Iodine health hazards and exposure limits
Iodine hazard summary
Iodine is a naturally occurring element found in sea water and in certain rocks and sediments. There are non radioactive and radioactive forms of iodine. Iodine is used as a disinfectant for cleaning surfaces and storage containers and is used in skin soaps and bandages, and for purifying water. Iodine is also added to some table salt to ensure that all people in the United States have enough iodine in their diet. Most radioactive iodine is manmade. It is used in medical tests and to treat certain diseases. Most radioactive forms of iodine change very quickly (seconds to days) to stable elements that are not radioactive. However, 129I (read as iodine 129) changes very slowly (over millions of years).
Source: Agency for Toxic Substances and Disease Registry (ATSDR)
Iodine occupational exposure limits
| Limit | Value | Source |
|---|---|---|
| PEL | 0.1 ppm (1 mg/m³) | Occupational Safety and Health Administration (OSHA) |
| PEL | C 0.1 ppm (1 mg/m3) | The National Institute for Occupational Safety and Health (NIOSH) |
| REL | 0.1 ppm (1 mg/m³) | Occupational Safety and Health Administration (OSHA) |
| REL | C 0.1 ppm (1 mg/m3) | The National Institute for Occupational Safety and Health (NIOSH) |
| IDLH | 2 ppm (NIOSH, 2024) | CAMEO Chemicals |
| IDLH | 2.0 [ppm] | Haz-Map, Information on Hazardous Chemicals and Occupational Diseases |
| IDLH | 2 ppm | Hazardous Substances Data Bank (HSDB) |
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
Iodine 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.
Iodine boiling point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Boiling point | 184.4 °C (363.9 °F) | HSDB | |
| 185 °C (365 °F) | NIOSH | ||
| 185 °C (365 °F) | at 760 mmHg | CAMEO |
Iodine melting point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Melting point | 113.7 °C (236.7 °F) | HSDB | |
| 113.33 °C (236 °F) | NIOSH |
Iodine density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Density | 4.93 g/cm³ | NIOSH | |
| 0.0113 g/cm³ | at 20 °C | HSDB |
Iodine solubility
| Property | Value | Conditions | Source |
|---|---|---|---|
| Solubility | Dissolves readily in chloroform, carbon tetrachloride, or carbon disulfide to form purple solns. | HSDB | |
| 2.719 g in cyclohexane; 23 g/100 cc in methanol at 25 °C; 20.5 g/100 cc in alcohol at 15 °C; 20.6 g/100 cc in ether at 17 °C | at 25 °C | HSDB |
Iodine vapor pressure
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor pressure | 0.233 mmHg | at 25 °C | HSDB |
| 0.3 mmHg | at 25 °C | NIOSH |
Iodine lower explosive limit (LEL)
| Property | Value | Conditions | Source |
|---|---|---|---|
| Lower explosive limit (LEL) | Noncombustible Solid | NIOSH |
Iodine vapor density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor density | 8.8 (air = 1) | ICSC | |
| 6.75 g/L at 101.3 MPa, 185 °C | at 185 °C, at 759813 mmHg | HSDB |
Iodine odor threshold
| Property | Value | Conditions | Source |
|---|---|---|---|
| Odor threshold | Odor low= 9.00 mg/cu m; Odor high= 9.00 mg/cu m; Irritating Concn= 2.0 mg/cu m | HSDB |
Iodine critical temperature and pressure
| Property | Value | Conditions | Source |
|---|---|---|---|
| Critical temperature and pressure | 546 °C (1014.8 °F) | HSDB |
Iodine corrosivity
| Property | Value | Conditions | Source |
|---|---|---|---|
| Corrosivity | Vapor is corrosive | HSDB |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
09 · Handling and storage
Iodine storage and handling
Iodine safe storage
Separated from incompatible materials. See Chemical Dangers. Well closed. Ventilation along the floor.
Source: ILO-WHO International Chemical Safety Cards (ICSCs)
Iodine storage conditions
Materials which are toxic as stored or which can decompose into toxic components ... Should be stored in a cool, well-ventilated place, out of the direct rays of the sun, away from areas of high fire hazard, and should be periodically inspected. Incompatible materials should be isolated ... .
Source: Hazardous Substances Data Bank (HSDB)
Iodine incompatible materials
The reaction between liquid chlorine and iodine is violent.
Source: Hazardous Substances Data Bank (HSDB)
Iodine reactivity
IODINE is an oxidizing agent. Reacts vigorously with reducing materials. Incompatible with powdered metals in the presence of water (ignites), with gaseous or aqueous ammonia (forms explosive products), with acetylene (reacts explosively), with acetaldehyde (violent reaction), with metal azides (forms yellow explosive iodoazides), with metal hydrides (ignites), with metal carbides (ignites easily), with potassium and sodium (forms shock-senstive explosive compounds) and with alkali-earth metals (ignites). Incompatible with ethanol, formamide, chlorine, bromine, bromine trifluoride, chlorine trifluoride.
Source: CAMEO Chemicals
Planning storage for a mix of chemicals? Check Iodine in the storage compatibility matrix →
10 · Transport
Iodine 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.
Iodine under UN 3495 — shipping name, class and packing group
Europe · ADR 2025, Table A
| Proper shipping name (3.1.2) | Class | Classification code | PG | Labels (column 5) |
|---|---|---|---|---|
| IODINE | 8 | CT2 | III | |
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) |
|---|---|---|---|
| Iodine | 8 | III | |
Source: 49 CFR 172.101 Hazardous Materials Table · eCFR, revision 2026-08-03. Class 8 is “Corrosive material” (49 CFR 173.2).
11 · Questions
Iodine — frequently asked questions
What is the CAS number of Iodine?
The CAS number of Iodine is 7553-56-2. Its EC number is 231-442-4.
What does a Iodine label have to show?
Under CLP Annex VI the label for Iodine carries the pictograms Exclamation mark and Environment and the signal word is Warning.
Is Iodine flammable?
CLP Annex VI assigns Iodine 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 Iodine a carcinogen?
CLP Annex VI records no harmonised carcinogenicity classification for Iodine. 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 Iodine?
The US occupational exposure limit reported for Iodine is 0.1 ppm (1 mg/m³) (Occupational Safety and Health Administration (OSHA)). 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 Iodine?
The boiling point reported for Iodine is 184.4 °C (363.9 °F) (HSDB).
What is the melting point of Iodine?
The melting point reported for Iodine is 113.7 °C (236.7 °F) (HSDB).
How should Iodine be stored?
Materials which are toxic as stored or which can decompose into toxic components ... Should be stored in a cool, well-ventilated place, out of the direct rays of the sun, away from areas of high fire hazard, and should be periodically inspected. Incompatible materials should be isolated ... . (Hazardous Substances Data Bank (HSDB))
Nearby
Substances next to Iodine
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