Safety data sheet reference · CAS 74-86-2
Acetylene SDS
also: acetylene MSDS · safety data sheet · C2H2 · CAS 74-86-2 · EC 200-816-9 · ethyne
Official PDF from supplier
This page is a reference, not the legal document.
CAS number
74-86-2
EC number
200-816-9
CLP Annex VI index
601-015-00-0
Molecular formula
C2H2
Molar mass
26.04 g/mol
§ 02 · Hazards identification
Acetylene harmonised EU classification
CLP Annex VI · Index 601-015-00-0. A supplier SDS may add self-classified hazards — this is the legal minimum.
§ 03 · Composition and identifiers
Acetylene molecular structure
Acetylene 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 · C2H2
Functional group
alkyne
Hybridisation
C sp ×2
Electron count
10 valence e⁻ · 0 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
Acetylene 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 ACETYLENE. 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.
Eye: FROSTBITE - If eye tissue is frozen, seek medical attention immediately; if tissue is not frozen, immediately and thoroughly flush the eyes with large amounts of water for at least 15 minutes, occasionally lifting the lower and upper eyelids. If irritation, pain, swelling, lacrimation, or photophobia persist, get medical attention as soon as possible.
Skin: FROSTBITE - If frostbite has occurred, seek medical attention immediately; do NOT rub the affected areas or flush them with water. In order to prevent further tissue damage, do NOT attempt to remove frozen clothing from frostbitten areas. If frostbite has NOT occurred, immediately and thoroughly wash contaminated skin with soap and water.
Breathing: FRESH AIR - If a person breathes large amounts of this chemical, move the exposed person to fresh air at once. Other measures are usually unnecessary.
Source: NIOSH, 2024 — via CAMEO Chemicals (NOAA), public domain.
§ 05 · Fire-fighting measures
Acetylene fire fighting measures
ERG 2024 · GUIDE 116 Gases - Flammable (Unstable)ERG guidance is written per response guide, not per substance — Guide 116 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: May explode in fire
Extinguishing media and tactics
DO NOT EXTINGUISH A LEAKING GAS FIRE UNLESS LEAK CAN BE STOPPED.
SMALL FIREDry chemical or CO2.
LARGE FIREWater spray or fog. If it can be done safely, move undamaged containers away from the area around the fire.
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: ACETYLENE.
§ 06 · Accidental release measures
Acetylene spill and leak response
Containment and clean-up
ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area. All equipment used when handling the product must be grounded. Stop leak if you can do it without risk. Do not touch or walk through spilled material. 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. 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.
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 800 meters (1/2 mile).
FIREIf tank, rail tank car or highway tank is involved in a fire, ISOLATE for 1600 meters (1 mile) in all directions; also, consider initial evacuation for 1600 meters (1 mile) in all directions.
Source: ERG, 2024 — via CAMEO Chemicals (NOAA), public domain. Entry: ACETYLENE.
§ 07 · Handling and storage
Acetylene computed storage compatibility
Derived from CLP Annex VI classification and CAMEO reactive-group data — not copied from a PDF.
⚠ Highly Flammable⚠ Peroxidizable Compound⚠ Polymerizable
↔ Keep separate
Full interactive verdict — reactions, gas release on contact, ADR forms →
§ 08 · Exposure controls
Acetylene exposure limits (IDLH)
IDLH
NIOSH lists acetylene in the Pocket Guide but has not established an IDLH value for it.
NIOSH Pocket Guide — Acetylene →
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
Acetylene physical properties
Fire-relevant values first — flash point and explosion limits decide the storage and ventilation regime.
Explosion limits
2.5 – 100 %
LEL / UEL in air, vol.
Autoignition
305 °C
Source: CAMEO Chemicals (NOAA, public domain); per-value source references stored in the database.
§ 10 · Stability and reactivity
Reactive group (CAMEO/NOAA): Alkynes, with Acetylenic Hydrogen. Our database documents 17 incompatible and 14 caution reaction-partner groups for acetylene — including which combinations release gas on contact. See the per-partner breakdown with gas release →
17
Incompatible
14
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
Acetylene road transport — ADR 2025
UN number
Proper shipping name
ACETYLENE, DISSOLVED
Class · PG
2
Classification code
4F
Transport category
2
ADR labels
2.1
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
ACETYLENE, SOLVENT FREE
Class · PG
2
Classification code
2F
Transport category
2
ADR labels
2.1
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
Acetylene 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 "acetylene MSDS" and a "acetylene SDS" refer to the same document — today it is issued as an SDS. Full breakdown of the differences →
Other compressed gases in our database
Substance profile
What acetylene 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 acetylene
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 acetylene
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 "acetylene MSDS" is today issued as an SDS.
What GHS pictograms does acetylene require?
Under the harmonised EU classification (CLP Annex VI), acetylene carries GHS02 and GHS04 with the signal word "Danger". Hazard statements: H220. A supplier's SDS may add self-classified hazards on top of this harmonised minimum.
Where can I download an official acetylene 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 ACETYLENE — confirm it matches the form in front of you.
01 · First aid
What to do for the person
Eye: FROSTBITE - If eye tissue is frozen, seek medical attention immediately; if tissue is not frozen, immediately and thoroughly flush the eyes with large amounts of water for at least 15 minutes, occasionally lifting the lower and upper eyelids. If irritation, pain, swelling, lacrimation, or photophobia persist, get medical attention as soon as possible.
Skin: FROSTBITE - If frostbite has occurred, seek medical attention immediately; do NOT rub the affected areas or flush them with water. In order to prevent further tissue damage, do NOT attempt to remove frozen clothing from frostbitten areas. If frostbite has NOT occurred, immediately and thoroughly wash contaminated skin with soap and water.
Breathing: FRESH AIR - If a person breathes large amounts of this chemical, move the exposed person to fresh air at once. Other measures are usually unnecessary.
02 · Fire
Extinguishing and tactics
Fire and explosion hazard
Behavior in Fire: May explode in fire
Extinguishing media and tactics
DO NOT EXTINGUISH A LEAKING GAS FIRE UNLESS LEAK CAN BE STOPPED.
SMALL FIREDry chemical or CO2.
LARGE FIREWater spray or fog. If it can be done safely, move undamaged containers away from the area around the fire.
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
ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area. All equipment used when handling the product must be grounded. Stop leak if you can do it without risk. Do not touch or walk through spilled material. 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. 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.
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 800 meters (1/2 mile).
FIREIf tank, rail tank car or highway tank is involved in a fire, ISOLATE for 1600 meters (1 mile) in all directions; also, consider initial evacuation for 1600 meters (1 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.