What is Acetone?

Acetone (chemical formula (CH₃)₂CO, CAS No. 67-64-1) is the simplest ketone and one of the most widely used industrial solvents. It is a colorless liquid with a fragrant, mint-like odor that mixes completely with water. It has a boiling point of 133°F (56°C), a flash point of 0°F (about -18°C), a lower explosive limit of 2.5% and an upper explosive limit of 12.8%. Acetone is not only an industrial chemical. The human body produces it naturally, and it is used commercially both as a solvent and as a building block for other chemicals.

For workplace safety, acetone’s most important property is its flammability. CCOHS describes it as a highly flammable liquid that can ignite at room temperature, and notes that its vapour can travel a considerable distance to an ignition source and flash back. It also warns that even dilute solutions of acetone in water may be flammable. Under WHMIS, acetone is classified as a Category 2 flammable liquid and a Category 2A eye irritant, with the signal word “danger”. It is not classified as a carcinogen. IARC has not specifically evaluated it, and ACGIH lists it as A4, not classifiable as a human carcinogen.

Common Industrial Uses of Acetone

Most acetone is made alongside another major chemical. According to ATSDR, approximately 90% of acetone in the United States is manufactured by cumene peroxidation, a process that oxidizes cumene and splits it into acetone and phenol. Readers of our benzene article will recognize cumene as one of benzene’s main derivatives, so the two chemicals share a supply chain.

Acetone’s largest manufacturing role is as a chemical intermediate. ATSDR reports that acetone is used primarily as an intermediate in the production of methyl methacrylate and bisphenol A. Methyl methacrylate is the starting material for acrylic plastics, and bisphenol A is used to make polycarbonate plastics and epoxy resins. Acetone is also commonly used as a solvent, particularly in the pharmaceutical industry, and is used to manufacture other chemicals such as methyl isobutyl ketone. The U.S. EPA adds cellulose acetate and methacrylic acid to the list of chemicals made using acetone.

Acetone’s second major role is as a solvent. EPA notes that it is used as a solvent for high-production-volume coatings and adhesives and is the primary ingredient in most commercial nail polish removers. Data reported to EPA under the Chemical Data Reporting rule show a long list of industrial functions. These include cleaning and degreasing solvents, laboratory chemicals, automotive refinishing mixtures, paint and coating additives, and adhesive and sealant chemicals.

How Common is Acetone in the Workplace?

Counting workplaces that use acetone is harder than it seems. ATSDR explains that the Toxics Release Inventory holds no information on facilities that manufacture or process acetone, because acetone is not required to be reported under that program. As a result, no current official count of acetone-using workplaces exists in the United States.

The best available U.S. figure is old but large. NIOSH’s National Occupational Exposure Survey, conducted in 1981 to 1983, estimated that acetone was present in 97,342 facilities across 358 industries, with 1,740,164 workers potentially exposed, including 540,313 women. The earlier National Occupational Hazard Survey of 1974 gave a similar picture, with an estimated 99,713 facilities and 1,287,794 employees. These figures are more than 40 years old, and solvent use has changed since then, so they should be treated as an indication of scale rather than a current count. No equivalent workplace count was located for Canada or the UK. CAREX Canada, the main Canadian source for this kind of data, tracks carcinogens and so does not cover acetone.

What the data do show clearly is that acetone is present across a very wide range of workplaces. For this article, those workplaces fall into two broad groups. This grouping is not an official classification. The first group is chemical plants that produce acetone or use it as a raw material, where large volumes are handled, mostly in closed systems. The second, much larger group is the many workplaces that use acetone as a solvent or cleaner. ATSDR identifies workers in certain paint, plastic, artificial fiber, and shoe factories as likely to be exposed to much higher levels of acetone than the general population. It also lists professional painters, salon workers, factory workers, and commercial and household cleaners as likely to face higher exposures.

Measured exposures in these settings are usually below the legal limits, but they vary widely. In a Finnish shoe factory, worker exposures ranged from 25.4 to 393.4 mg/m³ (roughly 11 to 165 ppm). In a study of 25 nail salons in New York City, Philadelphia and southern New Jersey, the total mean personal exposure to acetone was 18.51 ppm, and a NIOSH study of three salons found a mean full-shift exposure of 9.06 ppm. In a small U.S. printing factory, short-term average exposures ranged from 11.4 to 41.4 ppm during printing and cleaning activities.

Other industries with potential acetone exposure hazards include:

• Pharmaceutical manufacturing

• Paint, Coating and Adhesive manufacturing

• Plastics and fibre-reinforced plastics

• Footwear

• Printing

• Laboratories

• Automotive Finishing

Regardless of industry, workers must always be trained on the chemical dangers present both at their facilities as well as at their Point of Use.

Health Effects of Acetone

Short-term (acute) effects

Acetone has low toxicity compared with many industrial solvents, but high exposures do cause harm. According to ATSDR, breathing or swallowing high amounts of acetone over a short period can cause headaches, confusion, nausea, racing pulse, changes in the size and amount of blood cells, unconsciousness or coma. Breathing moderate to high amounts can also cause nose, throat, lung and eye irritation. Controlled human studies give a sense of the thresholds: volunteers experienced slight irritation at 300 ppm, while 500 ppm was tolerated. Liquid acetone is a significant eye hazard. CCOHS warns that it causes moderate to severe eye irritation, with sore, red and watering eyes, and that the vapour also irritates the eyes. On the skin, acetone causes dryness, irritation and cracking.

Acetone gives better warning of its presence than benzene does. ATSDR notes that a strong scent of acetone and irritation of the eyes, nose and throat are signs of moderate exposure. AIHA reports a mean odour detection threshold of 62 ppm, which is below the exposure limits in all three countries.

An important point about acetone’s acute hazard is that fire, not toxicity, drives the emergency limit. NIOSH has stated that a health-based IDLH (immediately dangerous to life or health) value of about 5,000 ppm would have been appropriate. Instead, the IDLH is set at 2,500 ppm, based strictly on safety considerations, because that is 10% of the lower explosive limit.

Long-term (chronic) effects

Evidence on long-term effects in humans is limited. CCOHS states that repeated skin contact can cause dry, red, cracked skin (dermatitis) and that acetone may harm the nervous system, but that conclusions cannot be drawn from the limited studies available. Animal studies raise some concerns. ATSDR reports that long-term exposure in animals has caused kidney, liver and nerve damage, birth defects and male infertility, but notes that it is not known whether long-term exposure affects people in the same way.

Acetone is not known to cause cancer. IARC has not specifically evaluated it, and ACGIH classifies it as A4, not classifiable as a human carcinogen. Exposure can be checked through biological monitoring. ACGIH sets a Biological Exposure Index of 25 mg/L of acetone in urine at the end of a shift.

Exposure Limits of Acetone

United States

The legally enforceable OSHA permissible exposure limit for acetone is 1,000 ppm (2,400 mg/m³) as an 8-hour time-weighted average. This limit dates from OSHA’s original 1971 tables. OSHA lowered it in 1989 to 750 ppm with a 1,000 ppm short-term limit, but a 1992 federal court decision vacated that update and the 1,000 ppm limit was restored. Some states set stricter limits. California’s Cal/OSHA limit, for example, is 500 ppm as an 8-hour average, with a 750 ppm short-term limit and a 3,000 ppm ceiling.

The non-binding U.S. benchmarks are considerably lower. NIOSH recommends a limit of 250 ppm as a 10-hour time-weighted average, and its IDLH value is 2,500 ppm. ACGIH’s Threshold Limit Value is 250 ppm as an 8-hour average with a 500 ppm short-term limit. This means the federal legal limit is four times higher than the current ACGIH guideline.

Canada

Occupational exposure limits are set by the provinces and territories, but for acetone they are consistent across the major jurisdictions. CCOHS notes that in many, but not all, Canadian jurisdictions the limits are similar to ACGIH TLVs, and advises employers to check with their local jurisdiction for exact details.

In Ontario, the limit under Regulation 833 is 250 ppm as an 8-hour average and 500 ppm as a short-term limit. British Columbia adopted the ACGIH values for acetone effective June 1, 2018, and WorkSafeBC lists the same 250 ppm and 500 ppm limits.

United Kingdom

In Great Britain, the legally binding Workplace Exposure Limit in HSE’s EH40 is 500 ppm (1,210 mg/m³) as an 8-hour average and 1,500 ppm (3,620 mg/m³) as a 15-minute short-term limit. Unlike benzene, acetone carries neither a Carc notation (for substances that can cause cancer) nor an Sk notation (for substances absorbed through the skin in harmful amounts). This means the core COSHH duty for acetone is to apply good control practice and keep exposure below the WEL, rather than the stricter “as low as reasonably practicable” duty that applies to carcinogens. Because acetone is highly flammable, employers must also manage fire and explosion risks under the Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR).

Recommended PPE for Acetone Handling

As with any hazardous chemical, PPE is the last line of defence. For acetone, the most important engineering controls address both vapour and fire. CCOHS recommends local exhaust ventilation and enclosure where necessary, and for large-scale use, non-sparking ventilation systems, explosion-proof equipment and intrinsically safe electrical systems. It also advises electrically bonding and grounding equipment and containers, because acetone can be ignited by static discharge.

United States

Unlike benzene, acetone has no substance-specific OSHA standard, so PPE requirements come from OSHA’s general standards: 29 CFR 1910.132 for PPE hazard assessment, 1910.133 for eye and face protection, and 1910.134 for respiratory protection. NIOSH provides respirator guidance for concentrations up to 2,500 ppm. A chemical cartridge respirator with organic vapor cartridges has an assigned protection factor of 10, and a powered air-purifying respirator with organic vapor cartridges has a factor of 25. A full-facepiece gas mask with an organic vapor canister has a factor of 50. For emergencies or unknown concentrations, NIOSH recommends a full-facepiece self-contained breathing apparatus operated in pressure-demand or other positive-pressure mode. Because acetone is volatile and loads cartridges quickly, the cartridge change schedule required under 1910.134 is especially important.

Glove choice is critical for acetone, because the most common disposable glove performs poorly against it. OSHA’s glove selection chart rates butyl rubber and natural rubber as very good against acetone, neoprene as good, and nitrile as poor. Butyl rubber is the usual choice for extended contact. Natural latex can cause allergic reactions, so it may not suit every worker. NIOSH also advises preventing skin and eye contact and removing clothing that becomes wet with acetone because of the fire risk.

Canada

CCOHS provides practical PPE guidance for acetone. For eyes and face, workers should wear chemical safety goggles and a face shield when contact is possible. For skin, workers should avoid repeated or prolonged contact and wear chemical protective clothing. Materials rated for 8 hours of protection include butyl rubber, Silver Shield® PE/EVAL/PE, several AlphaTec® and ChemMAX® grades, and a range of Tychem® suits. For respiratory protection, CCOHS follows the NIOSH recommendations described above and applies them only to NIOSH-approved respirators. Respirator programs in Canada should also follow CSA Standard Z94.4, Selection, Use and Care of Respirators, which provincial regulations reference for fit testing.

United Kingdom

COSHH requires PPE to be selected through a risk assessment, and HSE’s guide HSG53 is the main reference for respiratory protective equipment. Acetone needs a different filter from most organic solvents. Standard Type A (brown) filters are designed for organic vapours with a boiling point above 65°C. Acetone boils at about 56°C, so it requires a Type AX filter, which manufacturers such as Dräger describe as protecting against organic compounds with a boiling point of 65°C or below. AX filters are single-use: Dräger states they must be disposed of after use, and 3M states its AX filters are suitable for a single shift only. Tight-fitting RPE must be fit tested, and HSE recognises the Fit2Fit accreditation scheme as a way to demonstrate fit tester competence. Gloves should meet EN ISO 374 for chemical protection, with butyl rubber as the usual choice for extended contact. Where acetone vapour could form an explosive atmosphere, DSEAR also requires employers to consider antistatic footwear and clothing as part of controlling ignition sources.

Conclusion

Acetone is often treated as a low-risk solvent because it is familiar, smells strongly and has low toxicity compared with chemicals like benzene. Its flash point is well below room temperature, its vapour can travel to distant ignition sources, and high exposures can cause unconsciousness. Exposure limits also differ sharply between jurisdictions: the U.S. federal limit is four times higher than the limits in Canada and the ACGIH guideline. Employers should treat the strictest relevant value as their working target, and control acetone as a fire hazard first and a health hazard second.

Good hazard communication supports every one of these controls. Workers can only protect themselves if they know where acetone is, what its hazards are and what to do when something goes wrong. sdsLite gives employees and first responders credential-free access to safety data sheets through a QR code or URL, which matters in a spill or fire where speed counts. Its new Point of Use Libraries place job-specific chemical safety information exactly where acetone is used, such as a laboratory bench, a parts-cleaning station or a flammables cabinet. Each location gets its own label with a QR code linking to the relevant safety data sheets, the GHS pictograms for the chemicals used there and the date the information was last updated. Because acetone is so often decanted into wash bottles and small containers, sdsLite’s HazCom, WHMIS and COSHH compliant secondary labels help keep hazard information attached to the chemical wherever it goes. For sites that handle larger volumes, sdsPlus adds real-time chemical inventory across every location, container tracking and floor plans showing where chemicals and storage areas are located, along with storage area signage generated from what is actually stored in each zone. For a flammable solvent, knowing exactly how much is stored and where is a fire safety issue as much as a compliance one. Tools like these do not replace ventilation, ignition control or exposure monitoring. They do make it far easier to keep the right information in front of the right people, which is where hazard prevention begins.