Safety data sheet reference · CAS 7782-50-5
Chlorine SDS
also: chlorine MSDS · safety data sheet · Cl2 · CAS 7782-50-5 · EC 231-959-5 · chlorine gas
Official PDF from supplier
This page is a reference, not the legal document.
CAS number
7782-50-5
EC number
231-959-5
CLP Annex VI index
017-001-00-7
Molecular formula
Cl2
§ 02 · Hazards identification
Chlorine harmonised EU classification
CLP Annex VI · Index 017-001-00-7. A supplier SDS may add self-classified hazards — this is the legal minimum.
Precautionary statements
Codes ending in a colon introduce the action that follows — on a label they are printed as combined statements, such as P305+P351+P338.
§ 03 · Composition and identifiers
Chlorine molecular structure
Chlorine is a molecular compound. The skeletal formula below is drawn from its PubChem SMILES string, and every value in this section is computed from that structure.
2D skeletal formula · Cl2
Hybridisation
Cl sp³ ×2
Electron count
14 valence e⁻ · 6 lone pairs
Identifiers from PubChem (NIH, public domain). Structure diagram drawn with RDKit from the SMILES string. Geometry and hybridisation are computed from the connection table, not measured.
§ 04 · First-aid measures
Chlorine first aid measures
Call your national emergency number first. These are published first-aid measures, not medical advice, and they do not replace emergency services, a poison control centre or the supplier's safety data sheet.
§4–§6 below reproduce the CAMEO Chemicals entry CHLORINE. CAMEO publishes response data per product entry, so the entry can describe a solution, a refrigerated liquid or a molten form rather than the pure substance in §9 — check it matches what you are handling.
Warning: Effects may be delayed. Caution is advised. Chlorine is corrosive and may be converted to hydrochloric acid in the lungs.
Signs and Symptoms of Acute Chlorine Exposure: Signs and symptoms of acute exposure to chlorine may include tachycardia (rapid heart rate), hypertension (high blood pressure) followed by hypotension (low blood pressure), and cardiovascular collapse. Pulmonary edema and pneumonia are often seen. The eyes, nose, throat, and chest may sting or burn following exposure to chlorine. Cough with bloody sputum, a feeling of suffocation, dizziness, agitation, anxiety, nausea, and vomiting are common. Dermal exposure may result in sweating, pain, irritation, and blisters.
Emergency Life-Support Procedures: Acute exposure to chlorine may require decontamination and life support for the victims. Emergency personnel should wear protective clothing appropriate to the type and degree of contamination. Air-purifying or supplied-air respiratory equipment should also be worn, as necessary. Rescue vehicles should carry supplies such as chlorine-resistant plastic sheeting and disposable bags to assist in preventing spread of contamination.
Inhalation Exposure: 1. Move victims to fresh air. Emergency personnel should avoid self-exposure to chlorine. 2. Evaluate vital signs including pulse and respiratory rate, and note any trauma. If no pulse is detected, provide CPR. If not breathing, provide artificial respiration. If breathing is labored, administer oxygen or other respiratory support. 3. Obtain authorization and/or further instructions from the local hospital for administration of an antidote or performance of other invasive procedures. 4. Transport to a health care facility.
Dermal/Eye Exposure: 1. Remove victims from exposure. Emergency personnel should avoid self- exposure to chlorine. 2. Evaluate vital signs including pulse and respiratory rate, and note any trauma. If no pulse is detected, provide CPR. If not breathing, provide artificial respiration. If breathing is labored, administer oxygen or other respiratory support. 3. Remove contaminated clothing as soon as possible. 4. If eye exposure has occurred, eyes must be flushed with lukewarm water for at least 15 minutes. 5. Wash exposed skin areas for at least 15 minutes with soap and water. 6. Obtain authorization and/or further instructions from the local hospital for administration of an antidote or performance of other invasive procedures. 7. Transport to a health care facility.
Ingestion Exposure: No information is available.
Source: EPA, 1998 — via CAMEO Chemicals (NOAA), public domain.
§ 05 · Fire-fighting measures
Chlorine fire fighting measures
ERG 2024 · GUIDE 124 Gases - Toxic and/or Corrosive - OxidizingERG guidance is written per response guide, not per substance — Guide 124 covers every material assigned to it, so a few sentences reference other UN numbers in the same group.
Fire and explosion hazard
May ignite other combustible materials (wood, paper, oil, etc.). Mixture with fuels may cause explosion. Container may explode in heat of fire. Vapor explosion and poison hazard indoors, outdoors or in sewers. Hydrogen and chlorine mixtures (5-95%) are exploded by almost any form of energy (heat, sunlight, sparks, etc.). May combine with water or steam to produce toxic and corrosive fumes of hydrochloric acid. Emits highly toxic fumes when heated. Avoid plastics and rubber. Avoid heat and contact with hydrogen gas or powdered metals.
Extinguishing media and tactics
Evacuate area endangered by gas. Stay upwind; keep out of low areas. Wear positive pressure breathing apparatus and full protective clothing. Move container from fire area if you can do so without risk. Spray cooling water on containers that are exposed to flames until well after fire is out. If it is necessary to stop the flow of gas, use water spray to direct escaping gas away from those effecting shut-off.
Will not burn, but most combustible materials will burn in chlorine as they do in oxygen; flammable gases will form explosive mixtures with chlorine. Dry chemical, carbon dioxide, water spray, fog or foam.
Source: EPA, 1998 — via CAMEO Chemicals (NOAA), public domain. Entry: CHLORINE.
§ 06 · Accidental release measures
Chlorine spill and leak response
Containment and clean-up
Do not touch or walk through spilled material. Keep combustibles (wood, paper, oil, etc.) away from spilled material. Stop leak if you can do it without risk. Use water spray to reduce vapors or divert vapor cloud drift. Avoid allowing water runoff to contact spilled material. Do not direct water at spill or source of leak. If possible, turn leaking containers so that gas escapes rather than liquid. Prevent entry into waterways, sewers, basements or confined areas. Isolate area until gas has dispersed. Ventilate the area.
Initial isolation and evacuation
IMMEDIATE PRECAUTIONARY MEASUREIsolate spill or leak area for at least 100 meters (330 feet) in all directions.
SPILLSee ERG Tables 1 and 3 - Initial Isolation and Protective Action Distances on the UN/NA 1017 datasheet.
FIREIf tank, rail tank car or highway tank is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions.
Source: ERG, 2024 — via CAMEO Chemicals (NOAA), public domain. Entry: CHLORINE.
§ 07 · Handling and storage
Chlorine computed storage compatibility
Derived from CLP Annex VI classification and CAMEO reactive-group data — not copied from a PDF.
⚠ Strong Oxidizing Agent⚠ Water-Reactive
⛔ Never store with
↔ Keep separate
Full interactive verdict — reactions, gas release on contact, ADR forms →
§ 08 · Exposure controls
Chlorine exposure limits (IDLH)
IDLH
Immediately Dangerous to Life or Health
10 ppm
NIOSH Pocket Guide — Chlorine →
IDLH from the NIOSH Pocket Guide to Chemical Hazards (CDC, U.S. public domain), via CAMEO Chemicals. Occupational exposure limits — OSHA PEL, NIOSH REL and EU IOELV — are not published on this page yet.
§ 09 · Physical and chemical properties
Chlorine physical properties
Source: CAMEO Chemicals (NOAA, public domain); per-value source references stored in the database.
§ 10 · Stability and reactivity
Reactive group (CAMEO/NOAA): Halogenating Agents, Oxidizing Agents, Strong. Our database documents 117 incompatible and 12 caution reaction-partner groups for chlorine — including which combinations release gas on contact. See the per-partner breakdown with gas release →
117
Incompatible
12
Caution
§ 13 · Disposal considerations
Dispose of waste and residues in accordance with local and national regulations — in the EU under the Waste Framework Directive 2008/98/EC. Never discharge to drains or municipal waste; hand contaminated packaging and unused product to an authorised waste-disposal company. The supplier's SDS section 13 lists the applicable waste codes for the specific product.
§ 14 · Transport information
Chlorine road transport — ADR 2025
UN number
Proper shipping name
CHLORINE
Class · PG
2
Classification code
2TOC
Transport category
1
ADR labels
2.3, 5.1, 8
Hazard ID (Kemler) / UN plate
Top: hazard identification number (Kemler). Bottom: UN number — as carried on the orange plate of the transport unit.
UN number
Proper shipping name
CHLORINE, ADSORBED
Class · PG
2
Classification code
9TOC
Transport category
1
ADR labels
2.3, 5.1, 8
Source: UN ADR 2025 (ECE/TRANS/352), Table A. Road (ADR) only — for sea (IMDG) and air (IATA), consult the supplier's SDS §14.
MSDS vs SDS
Chlorine MSDS vs SDS: is there a difference?
MSDS (Material Safety Data Sheet) is the older name for the same document. In the US, OSHA's Hazard Communication Standard (2012) adopted the GHS-standardised 16-section Safety Data Sheet; in the EU the format is set by REACH Annex II. So a "chlorine MSDS" and a "chlorine SDS" refer to the same document — today it is issued as an SDS. Full breakdown of the differences →
Other oxidizers in our database
Substance profile
What chlorine is
Physical and chemical properties with the conditions each value was measured under, synonyms, formula and the harmonised CLP classification →
Compliance hub
From classification to SDS
The classification above corresponds to Section 2 of a Safety Data Sheet. Learn how a compliant 16-section SDS is structured and authored →
GHS label maker
Build the label for chlorine
Pictograms, signal word and H-statements combined into a compliant label layout →
§ 16 · Sources
- Classification: Regulation (EC) No 1272/2008 (CLP), Annex VI
- Transport: UN ADR 2025 (UNECE), Table A
- Reactivity: NOAA CAMEO Chemicals reactive-group matrix (public domain)
- Physical properties: CAMEO Chemicals (NOAA, public domain) — per-value source references stored in the database
- Emergency response (§4–§6): ERG 2024 (PHMSA) · NIOSH Pocket Guide (CDC) · CHRIS (USCG) · NTP · EPA — via CAMEO Chemicals (NOAA), all US federal public domain, reproduced verbatim
- Substance data: PubChem · ECHA
Reference aid only. This page summarises the harmonised EU classification and computed storage guidance — it is not a Safety Data Sheet and does not replace one. Always verify hazards, handling and storage against the supplier's SDS (sections 7 and 10) and local regulations before use. Page updated 2026-08-11.
Frequently asked questions about chlorine
Is an MSDS the same as an SDS?
In practice, yes. MSDS (Material Safety Data Sheet) is the older name for the same document. In the US, OSHA's Hazard Communication Standard (2012) adopted the GHS-standardised 16-section Safety Data Sheet; in the EU the SDS format is set by REACH Annex II. A document you find labelled "chlorine MSDS" is today issued as an SDS.
What GHS pictograms does chlorine require?
Under the harmonised EU classification (CLP Annex VI), chlorine carries GHS03 and GHS04 and GHS06 and GHS09 with the signal word "Danger". Hazard statements: H270, H331, H335, H315, H319, H400. A supplier's SDS may add self-classified hazards on top of this harmonised minimum.
What should chlorine never be stored with?
Based on its storage classes (Oxidizers, Acute toxics), chlorine must not share storage with: Cyanides & sulfides; Flammable liquids; Flammable solids; Mineral acids; Organic acids; Organic peroxides & self-reactives; Reactive metals; Water-reactives. Verify against the supplier's SDS sections 7 and 10 before finalising storage.
Where can I download an official chlorine SDS PDF?
From your own supplier — an SDS is issued per product and supplier, so the correct PDF for an inspection is the one matching the product you actually purchased. The supplier links on this page lead to the official SDS libraries of major distributors.
Call emergency services first
112 in the EU · 911 in the US. This screen is published response information, not medical advice, and it does not replace emergency services, a poison centre or the supplier's safety data sheet.
Text below is the CAMEO Chemicals entry CHLORINE — confirm it matches the form in front of you.
01 · First aid
What to do for the person
Warning: Effects may be delayed. Caution is advised. Chlorine is corrosive and may be converted to hydrochloric acid in the lungs.
Signs and Symptoms of Acute Chlorine Exposure: Signs and symptoms of acute exposure to chlorine may include tachycardia (rapid heart rate), hypertension (high blood pressure) followed by hypotension (low blood pressure), and cardiovascular collapse. Pulmonary edema and pneumonia are often seen. The eyes, nose, throat, and chest may sting or burn following exposure to chlorine. Cough with bloody sputum, a feeling of suffocation, dizziness, agitation, anxiety, nausea, and vomiting are common. Dermal exposure may result in sweating, pain, irritation, and blisters.
Emergency Life-Support Procedures: Acute exposure to chlorine may require decontamination and life support for the victims. Emergency personnel should wear protective clothing appropriate to the type and degree of contamination. Air-purifying or supplied-air respiratory equipment should also be worn, as necessary. Rescue vehicles should carry supplies such as chlorine-resistant plastic sheeting and disposable bags to assist in preventing spread of contamination.
Inhalation Exposure: 1. Move victims to fresh air. Emergency personnel should avoid self-exposure to chlorine. 2. Evaluate vital signs including pulse and respiratory rate, and note any trauma. If no pulse is detected, provide CPR. If not breathing, provide artificial respiration. If breathing is labored, administer oxygen or other respiratory support. 3. Obtain authorization and/or further instructions from the local hospital for administration of an antidote or performance of other invasive procedures. 4. Transport to a health care facility.
Dermal/Eye Exposure: 1. Remove victims from exposure. Emergency personnel should avoid self- exposure to chlorine. 2. Evaluate vital signs including pulse and respiratory rate, and note any trauma. If no pulse is detected, provide CPR. If not breathing, provide artificial respiration. If breathing is labored, administer oxygen or other respiratory support. 3. Remove contaminated clothing as soon as possible. 4. If eye exposure has occurred, eyes must be flushed with lukewarm water for at least 15 minutes. 5. Wash exposed skin areas for at least 15 minutes with soap and water. 6. Obtain authorization and/or further instructions from the local hospital for administration of an antidote or performance of other invasive procedures. 7. Transport to a health care facility.
Ingestion Exposure: No information is available.
02 · Fire
Extinguishing and tactics
Fire and explosion hazard
May ignite other combustible materials (wood, paper, oil, etc.). Mixture with fuels may cause explosion. Container may explode in heat of fire. Vapor explosion and poison hazard indoors, outdoors or in sewers. Hydrogen and chlorine mixtures (5-95%) are exploded by almost any form of energy (heat, sunlight, sparks, etc.). May combine with water or steam to produce toxic and corrosive fumes of hydrochloric acid. Emits highly toxic fumes when heated. Avoid plastics and rubber. Avoid heat and contact with hydrogen gas or powdered metals.
Extinguishing media and tactics
Evacuate area endangered by gas. Stay upwind; keep out of low areas. Wear positive pressure breathing apparatus and full protective clothing. Move container from fire area if you can do so without risk. Spray cooling water on containers that are exposed to flames until well after fire is out. If it is necessary to stop the flow of gas, use water spray to direct escaping gas away from those effecting shut-off.
Will not burn, but most combustible materials will burn in chlorine as they do in oxygen; flammable gases will form explosive mixtures with chlorine. Dry chemical, carbon dioxide, water spray, fog or foam.
03 · Spill
Containment, isolation, evacuation
Containment and clean-up
Do not touch or walk through spilled material. Keep combustibles (wood, paper, oil, etc.) away from spilled material. Stop leak if you can do it without risk. Use water spray to reduce vapors or divert vapor cloud drift. Avoid allowing water runoff to contact spilled material. Do not direct water at spill or source of leak. If possible, turn leaking containers so that gas escapes rather than liquid. Prevent entry into waterways, sewers, basements or confined areas. Isolate area until gas has dispersed. Ventilate the area.
Initial isolation and evacuation
IMMEDIATE PRECAUTIONARY MEASUREIsolate spill or leak area for at least 100 meters (330 feet) in all directions.
SPILLSee ERG Tables 1 and 3 - Initial Isolation and Protective Action Distances on the UN/NA 1017 datasheet.
FIREIf tank, rail tank car or highway tank is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions.
Sources: ERG 2024 (PHMSA) · NIOSH Pocket Guide (CDC) · CHRIS (USCG) · NTP · EPA — via CAMEO Chemicals (NOAA), public domain. Text reproduced verbatim.