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General product and safety information only; this page is not medical advice and does not give procedures.
Short answer
Ethyl alcohol is another name for ethanol (CH3CH2OH, CAS 64-17-5), a clear, colorless, flammable liquid. US federal regulation (27 CFR 21.11) covers it “from whatever source or by whatever process produced” and sorts it into undenatured and denatured categories with different permit rules. As a disinfectant it works best diluted in water (60% to 90%), not as pure alcohol.
Definition and scope
The NIOSH Pocket Guide lists the synonyms “alcohol, cologne spirit, ethanol, EtOH, grain alcohol” and describes a clear, colorless liquid with a weak, ethereal, vinous odor. So “ethyl alcohol”, “ethanol”, “EtOH” and “grain alcohol” name the same substance. It is a different chemical from isopropyl alcohol; see what isopropyl alcohol is and the isopropyl alcohol vs ethanol comparison.
The regulatory meaning is narrower than the chemical one. Under 27 CFR 21.11, “proof” is the ethyl alcohol content of a liquid at 60 degrees Fahrenheit, stated as twice the percent of ethyl alcohol by volume. A liquid that is 50% ethyl alcohol by volume is therefore 100 proof.
How it is used in practice
The CDC disinfection guideline describes alcohols as rapidly bactericidal against vegetative bacteria, and lists tuberculocidal, fungicidal and virucidal activity. The likely mechanism is protein denaturation. Uses the CDC cites include thermometers, stethoscopes, scissors, small surfaces, vial stoppers (as towelettes) and external equipment surfaces.
The CDC also states the limits, and they matter more than the uses:
- Optimum activity is at 60% to 90% alcohol in water (volume per volume); activity drops sharply below 50%.
- Absolute ethanol is less bactericidal than alcohol-water mixtures, because water speeds protein denaturation.
- Ethyl alcohol at 60% to 80% inactivates lipophilic viruses and many hydrophilic viruses, but not hepatitis A virus or poliovirus.
- Alcohols are not sporicidal.
- Alcohol is not recommended for sterilizing medical and surgical materials: it has no sporicidal action and cannot penetrate protein-rich material. The CDC notes that FDA has cleared no liquid chemical sterilant or high-level disinfectant with alcohol as its main active ingredient.
- It evaporates rapidly, so extended contact is hard to achieve unless items are immersed.
Types and classifications
“Types of ethyl alcohol” has two separate meanings: how it is classified for regulatory purposes, and what strength is used for disinfection.
| Category | What the source says | Source |
|---|---|---|
| Alcohol (ethyl alcohol) | The spirits known as ethyl alcohol, ethanol or spirits of wine, from whatever source or by whatever process produced. | 27 CFR 21.11 |
| Denatured spirits | Alcohol or rum to which denaturants have been added as provided in the regulation. A denaturant is a material authorized to be added to make the spirits unfit for beverage or internal human medicinal use. | 27 CFR 21.11 |
| Completely denatured alcohol (CDA) | Alcohol denatured under the completely denatured alcohol formulas (27 CFR 21 subpart C). TTB states that a permit is not needed to purchase it. | 27 CFR 21.11; TTB |
| Specially denatured alcohol (SDA) | Alcohol denatured under the specially denatured alcohol formulas (subpart D). TTB states that an industrial alcohol user permit is needed to procure, use, recover or deal in it. | 27 CFR 21.11; TTB |
| Aqueous disinfectant strength | 60% to 90% in water (v/v) is the optimum range; activity falls sharply below 50%. | CDC |
Where it matters for labs, clinics and supply decisions
The NIOSH Pocket Guide gives the numbers that usually appear on a label or safety data sheet (SDS) for ethyl alcohol. Use them as a cross-check against the SDS actually supplied with a product, since a product may be a mixture or contain a denaturant.
| Property | NIOSH value |
|---|---|
| Flash point | 55 F |
| Lower / upper explosive limit | 3.3% / 19% |
| Boiling point | 173 F |
| Vapor pressure | 44 mmHg |
| Specific gravity | 0.79 |
| NIOSH REL and OSHA PEL (TWA) | 1000 ppm (1900 mg/m3) |
| IDLH | 3300 ppm [10% LEL] |
| Incompatibilities | Strong oxidizers, potassium dioxide, bromine pentafluoride, acetyl bromide, acetyl chloride, platinum, sodium |
NIOSH lists inhalation, ingestion and skin or eye contact as exposure routes, with irritation of the eyes, skin and nose, headache, drowsiness and lassitude as symptoms. For storage context see flammable liquid storage cabinet requirements; for how exposure limits are defined, see permissible exposure limits (PELs, TLVs, RELs); for reading hazard labels, see GHS labels, pictograms and hazard statements.
The CDC adds that alcohol is flammable and should be stored in a cool, well-ventilated place, and that prolonged use can damage some equipment: it can damage shellac-mounted lensed instruments, swell or harden rubber and plastic tubing, bleach rubber and plastic tiles, and damage tonometer tips. Where alcohol sits among other chemical disinfectant classes is covered in types of disinfectants.
Common misunderstandings
Ethyl alcohol, ethanol and grain alcohol are different products
They are names for the same substance. What differs between products is concentration, water content and, for industrial alcohol, whether and how it is denatured.
Stronger is better for disinfection
The CDC states the opposite: absolute ethanol is less bactericidal than alcohol-water mixtures, and the optimum range is 60% to 90%.
Denatured alcohol is just a label
Under 27 CFR 21.11 denaturing is a regulatory category: a denaturant makes the spirits unfit for beverage or internal human medicinal use, and CDA and SDA carry different permit rules.
Alcohol sterilizes
It does not. It is not sporicidal and is not recommended for sterilizing medical or surgical materials.
FAQ
What is ethyl alcohol?
Ethanol, CH3CH2OH (CAS 64-17-5), a clear, colorless, flammable liquid also called EtOH, grain alcohol and cologne spirit.
Is ethanol a disinfectant?
Ethyl alcohol in water is bactericidal, tuberculocidal, fungicidal and virucidal against many viruses, with optimum activity at 60% to 90%. It is not sporicidal and does not inactivate hepatitis A virus or poliovirus (CDC).
What are examples of ethyl alcohol?
Under the regulation’s categories: alcohol (undenatured ethyl alcohol), completely denatured alcohol, specially denatured alcohol, and ethanol-water mixtures at disinfectant strengths.
How is ethyl alcohol classified?
By NIOSH it is a flammable liquid with a flash point of 55 F; by federal alcohol regulation it is undenatured spirits, CDA or SDA.
What should an ethyl alcohol label or SDS show?
The values to cross-check against the SDS supplied with the product are flash point (55 F), explosive limits (3.3% to 19%), exposure limits (1000 ppm TWA) and incompatibilities, as listed in the NIOSH table above.
What are the types of ethyl alcohol?
Undenatured ethyl alcohol, completely denatured alcohol (CDA) and specially denatured alcohol (SDA) in federal regulation, plus alcohol-water mixtures at disinfectant strengths. The table above lists each with its source.
Sources
- NIOSH Pocket Guide to Chemical Hazards, Ethyl alcohol: https://www.cdc.gov/niosh/npg/npgd0262.html (checked 2026-10-30).
- CDC, Guideline for Disinfection and Sterilization in Healthcare Facilities, Chemical Disinfectants: https://www.cdc.gov/infection-control/hcp/disinfection-sterilization/chemical-disinfectants.html (checked 2026-10-30).
- 27 CFR 21.11, Definitions: https://www.law.cornell.edu/cfr/text/27/21.11 (checked 2026-10-30).
- TTB, Specially Denatured Alcohol tutorial: https://www.ttb.gov/regulated-commodities/industrial-alcohol/sda-tutorial/sdamenu2sub1 (checked 2026-10-30).
