Safety data sheet reference · CAS 7782-44-7
Oxygen SDS
also: oxygen MSDS · safety data sheet · O2 · CAS 7782-44-7 · EC 231-956-9 · compressed oxygen · liquid oxygen
Official PDF from supplier
This page is a reference, not the legal document.
CAS number
7782-44-7
EC number
231-956-9
CLP Annex VI index
008-001-00-8
Molecular formula
O2
§ 02 · Hazards identification
Oxygen harmonised EU classification
CLP Annex VI · Index 008-001-00-8. 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
Oxygen molecular structure
Oxygen 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 · O2
Hybridisation
O sp² ×2
Electron count
12 valence e⁻ · 4 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
Oxygen 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 OXYGEN. 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.
INHALATION
in all but the most severe cases (pneumonia), recovery is rapid after reduction of oxygen pressure; supportive treatment should include immediate sedation, anticonvulsive therapy if needed, and rest.
EYES
treat frostbite burns.
SKIN
treat frostbite; soak in lukewarm water.
Source: USCG, 1999 — via CAMEO Chemicals (NOAA), public domain.
§ 05 · Fire-fighting measures
Oxygen fire fighting measures
ERG 2024 · GUIDE 122 Gases - Oxidizing (Including Refrigerated Liquids)ERG guidance is written per response guide, not per substance — Guide 122 covers every material assigned to it, so a few sentences reference other UN numbers in the same group.
Fire and explosion hazard
Behavior in Fire: Increases intensity of any fire. Mixtures of liquid oxygen and any fuel are highly explosive.
Extinguishing media and tactics
Use extinguishing agent suitable for type of surrounding fire.
SMALL FIREDry chemical or CO2.
LARGE FIREWater spray, fog or regular foam. If it can be done safely, move undamaged containers away from the area around the fire. Damaged cylinders should be handled only by specialists.
FIRE INVOLVING TANKSFight fire from maximum distance or use unmanned master stream devices or monitor nozzles. Cool containers with flooding quantities of water until well after fire is out. Do not direct water at source of leak or safety devices; icing may occur. Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank. ALWAYS stay away from tanks in direct contact with flames. For massive fire, use unmanned master stream devices or monitor nozzles; if this is impossible, withdraw from area and let fire burn.
Source: ERG, 2024 — via CAMEO Chemicals (NOAA), public domain. Entry: OXYGEN.
§ 06 · Accidental release measures
Oxygen spill and leak response
Containment and clean-up
Keep combustibles (wood, paper, oil, etc.) away from spilled material. Do not touch or walk through spilled material. Stop leak if you can do it without risk. If possible, turn leaking containers so that gas escapes rather than liquid. Do not direct water at spill or source of leak. Use water spray to reduce vapors or divert vapor cloud drift. Avoid allowing water runoff to contact spilled material. Prevent entry into waterways, sewers, basements or confined areas. Allow substance to evaporate. Isolate area until gas has dispersed. CAUTION: When in contact with refrigerated/cryogenic liquids, many materials become brittle and are likely to break without warning.
Initial isolation and evacuation
IMMEDIATE PRECAUTIONARY MEASUREIsolate spill or leak area for at least 100 meters (330 feet) in all directions.
LARGE SPILLConsider initial downwind evacuation for at least 500 meters (1/3 mile).
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: OXYGEN.
§ 07 · Handling and storage
Oxygen computed storage compatibility
Derived from CLP Annex VI classification and CAMEO reactive-group data — not copied from a PDF.
⚠ Strong Oxidizing Agent
⛔ Never store with
↔ Keep separate
Full interactive verdict — reactions, gas release on contact, ADR forms →
§ 09 · Physical and chemical properties
Oxygen physical properties
Source: CAMEO Chemicals (NOAA, public domain); per-value source references stored in the database.
§ 10 · Stability and reactivity
Reactive group (CAMEO/NOAA): Oxidizing Agents, Strong. Our database documents 59 incompatible and 5 caution reaction-partner groups for oxygen — including which combinations release gas on contact. See the per-partner breakdown with gas release →
59
Incompatible
5
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
Oxygen road transport — ADR 2025
UN number
Proper shipping name
OXYGEN, COMPRESSED
Class · PG
2
Classification code
1O
Transport category
3
ADR labels
2.2, 5.1
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
OXYGEN, REFRIGERATED LIQUID
Class · PG
2
Classification code
3O
Transport category
3
ADR labels
2.2, 5.1
Hazard ID (Kemler) / UN plate
Top: hazard identification number (Kemler). Bottom: UN number — as carried on the orange plate of the transport unit.
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
Oxygen 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 "oxygen MSDS" and a "oxygen 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 oxygen 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 oxygen
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 oxygen
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 "oxygen MSDS" is today issued as an SDS.
What GHS pictograms does oxygen require?
Under the harmonised EU classification (CLP Annex VI), oxygen carries GHS03 and GHS04 with the signal word "Danger". Hazard statements: H270. A supplier's SDS may add self-classified hazards on top of this harmonised minimum.
What should oxygen never be stored with?
Based on its storage class (Oxidizers), oxygen 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 oxygen 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 OXYGEN — confirm it matches the form in front of you.
01 · First aid
What to do for the person
INHALATION
in all but the most severe cases (pneumonia), recovery is rapid after reduction of oxygen pressure; supportive treatment should include immediate sedation, anticonvulsive therapy if needed, and rest.
EYES
treat frostbite burns.
SKIN
treat frostbite; soak in lukewarm water.
02 · Fire
Extinguishing and tactics
Fire and explosion hazard
Behavior in Fire: Increases intensity of any fire. Mixtures of liquid oxygen and any fuel are highly explosive.
Extinguishing media and tactics
Use extinguishing agent suitable for type of surrounding fire.
SMALL FIREDry chemical or CO2.
LARGE FIREWater spray, fog or regular foam. If it can be done safely, move undamaged containers away from the area around the fire. Damaged cylinders should be handled only by specialists.
FIRE INVOLVING TANKSFight fire from maximum distance or use unmanned master stream devices or monitor nozzles. Cool containers with flooding quantities of water until well after fire is out. Do not direct water at source of leak or safety devices; icing may occur. Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank. ALWAYS stay away from tanks in direct contact with flames. For massive fire, use unmanned master stream devices or monitor nozzles; if this is impossible, withdraw from area and let fire burn.
03 · Spill
Containment, isolation, evacuation
Containment and clean-up
Keep combustibles (wood, paper, oil, etc.) away from spilled material. Do not touch or walk through spilled material. Stop leak if you can do it without risk. If possible, turn leaking containers so that gas escapes rather than liquid. Do not direct water at spill or source of leak. Use water spray to reduce vapors or divert vapor cloud drift. Avoid allowing water runoff to contact spilled material. Prevent entry into waterways, sewers, basements or confined areas. Allow substance to evaporate. Isolate area until gas has dispersed. CAUTION: When in contact with refrigerated/cryogenic liquids, many materials become brittle and are likely to break without warning.
Initial isolation and evacuation
IMMEDIATE PRECAUTIONARY MEASUREIsolate spill or leak area for at least 100 meters (330 feet) in all directions.
LARGE SPILLConsider initial downwind evacuation for at least 500 meters (1/3 mile).
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.