Acetone (CAS 67-64-1), also called propan-2-one, has the formula C3H6O and a molecular weight of about 58.08. It is a colourless, volatile, water-miscible liquid with a boiling point near 56 degrees Celsius. The two properties that drive its handling rules are volatility and flammability.
| about 56 degrees Celsius | |
| about minus 20 degrees Celsius | |
| about 465 degrees Celsius | |
| about 2.5 to 12.8 percent by volume | |
| UN 1090, flammable liquid, class 3, packing group II |
Because the flash point is well below any normal working temperature, acetone releases ignitable vapour at ambient conditions. Repeated skin contact also defats the skin, and vapour at high concentration causes eye, nose and throat irritation and central nervous system effects such as headache and dizziness.
Work with acetone in a fume hood or under local exhaust ventilation. Local extraction at the point of use is more effective than general dilution ventilation, because vapour is denser than air and collects in pits, trenches and low areas. Transfer operations between drums and containers must be bonded and grounded, and pumps, stirrers and lighting in the area must be rated for use in a flammable atmosphere. Open flames, hot plates, welding and non-rated electrical equipment should be excluded from the zone. Acetone can generate static charge when poured or filtered, so do not use plastic containers or non-conductive liners for transfer.
Glove selection matters: acetone permeates nitrile and latex gloves quickly, so butyl rubber, laminated film or other solvent-resistant gloves rated for ketones are the correct choice, and they must be changed as soon as breakthrough occurs. Safety goggles or a face shield protect the eyes, since splashes cause irritation and corneal damage. An apron or chemical-resistant suit protects clothing and skin during drum handling. Where ventilation cannot keep vapour below the exposure limit, use a respirator fitted with an organic vapour cartridge, and verify fit testing and cartridge change-out schedules.
Occupational exposure limits for acetone appear in GBZ 2.1-2019, the national standard on occupational exposure limits for hazardous agents in the workplace, which sets a time-weighted average permissible concentration of 300 mg per cubic metre for an eight-hour shift and a short-term exposure limit of 450 mg per cubic metre. Where these values are difficult to meet, fixed-point or personal sampling should be used to verify control, and the results recorded.
For fires, use dry powder, carbon dioxide or alcohol-resistant foam. Water is not suitable as an extinguishing medium for a running acetone fire because it can spread the burning liquid, although a water spray is useful for cooling exposed containers and protecting personnel. Never allow an acetone fire to burn in a confined space without cooling the vessel, because vapour pressure rises quickly with temperature.
For small spills, isolate the area, remove ignition sources, ventilate, and absorb the liquid with sand, vermiculite or an inert absorbent, then place it in a closed, labelled container for disposal. Prevent entry into drains, basements and confined spaces. For larger releases, evacuate, call the emergency response team and keep unprotected people upwind.
If vapour has been inhaled, move the person to fresh air and keep them warm and at rest. For skin contact, remove contaminated clothing and wash with plenty of water. For eye contact, flush with water for at least 15 minutes and obtain medical attention. If the material is swallowed, do not induce vomiting and seek medical help immediately.
Store acetone in a cool, dry, well-ventilated area away from heat, oxidising agents and strong acids or bases, in closed containers that are grounded and bonded. Warehouse storage should follow the applicable national rules for hazardous chemical storage, such as GB 15603, including segregation from oxidisers and from materials that generate heat. Transport is classified under UN 1090 with the corresponding flammable liquid label and packaging group. Waste acetone, contaminated absorbents and rinse solvent are hazardous waste and must go to a licensed treatment route, not to general refuse or the drainage system.
Q:
A: Its flash point is about minus 20 degrees Celsius, so it gives off ignitable vapour at any normal working temperature, and the vapour can travel to an ignition source some distance away.
Q:
A: Butyl rubber and laminated film gloves are the usual choices. Nitrile and latex gloves are permeated quickly by acetone and are not suitable for anything more than brief incidental contact.
Q:
A: GBZ 2.1-2019 sets a time-weighted average limit of 300 mg per cubic metre and a short-term limit of 450 mg per cubic metre. Air monitoring should confirm that these values are met.
Q:
A: Not as the primary extinguishing agent, because it can spread a burning pool. Use dry powder, carbon dioxide or alcohol-resistant foam, and keep a water spray for cooling containers.
Q:
A: Remove ignition sources, ventilate the area, and absorb the liquid with sand or vermiculite. Seal the absorbent in a labelled container for hazardous waste disposal and keep the spill out of drains and confined spaces.
Q:
A: As UN 1090, a class 3 flammable liquid in packing group II, which sets the packaging, labelling and documentation requirements for road, sea and air movement.
