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Safety Data Sheet · SDS / MSDS

Acetylene C₂H₂ — SDS

Ethyne · Dissolved Acetylene (DA) · Welding gas
UN No: 1001CAS: 74-86-2Class: 2.1 — Flammable gasSignal: Danger
4
3
1
NFPA 704: Health 1 · Fire 4 · Reactivity 3
Blue = health · Red = flammability · Yellow = reactivity.

Hazard identification (GHS)

  • Extremely flammable gas (H220).
  • Contains gas under pressure; may explode if heated (H280).
  • May react, decompose or explode under pressure, heat or shock even without air.
  • Forms explosive acetylides with copper, silver and mercury.

First-aid measures

Inhalation: move the person to fresh air at once. If breathing has stopped, give artificial respiration; administer oxygen if trained. Get medical help immediately. Frostbite from escaping gas: flush with lukewarm water, do not rub.

Handling & storage

  • Store and use only with adequate explosion-proof ventilation; acetylene is lighter-limit sensitive.
  • Keep cylinders upright, valve caps on, below 52 °C (125 °F), away from ignition sources.
  • Separate from oxygen and other oxidisers by at least 6 m (20 ft) or a fire-rated wall.
  • Never draw off gas faster than 1/7 of cylinder contents per hour; never exceed 15 psig line pressure.
  • Use only approved regulators and flashback arrestors; never use copper or copper-alloy piping.

Physical & chemical properties

AppearanceColourless gas
OdourGarlic-like (commercial purity)
Molecular weight26.04
Boiling point−84 °C (sublimes)
Flammable limits in air2.5 – 100 %
Auto-ignition305 °C
Relative density (air = 1)0.91

Stability & reactivity

Unstable if compressed alone; stable dissolved in acetone/DMF over a porous mass as shipped. Avoid heat, shock, and contact with copper, silver, mercury and strong oxidisers. Hazardous decomposition products: carbon monoxide, carbon dioxide, hydrogen.

Transport information

Acetylene, dissolved — Class 2.1, UN 1001, Label: Flammable gas.

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This is a summary Safety Data Sheet for reference. For the full signed SDS, grades, purity and cylinder options, contact our team.

Frequently asked questions

Acetylene (C₂H₂) is classified as 2.1 — Flammable gas. Yes — it is a flammable gas.
Acetylene is shipped as Acetylene, dissolved — Class 2.1, UN 1001, Label: Flammable gas.
The CAS number of Acetylene is 74-86-2.
This page is the IIGAS Acetylene (C₂H₂) Safety Data Sheet summary. For the full signed SDS document, contact IIGAS at marketing@iigas.com.

Reference summary only, compiled by International Industrial Gases Ltd (updated 2026-07-20). Values are for the compressed-gas form. It does not replace the full signed Safety Data Sheet supplied with the product; always follow the SDS provided with your cylinders.

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