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Isopropyl alcohol (also called isopropanol, 2-propanol or IPA) is a colorless, flammable liquid that is used as a disinfectant for small surfaces and certain equipment. The US National Institute for Occupational Safety and Health (NIOSH) lists “rubbing alcohol” as one of its synonyms. This page describes products and general use; it is not medical advice.
Who uses it: clinic and laboratory staff, procurement and supply buyers, and students who need to read a product label or safety data sheet correctly.
What isopropyl alcohol is
Isopropyl alcohol is a simple alcohol with the formula (CH3)2CHOH, CAS registry number 67-63-0 and a molecular weight of 60.1. NIOSH describes it as a colorless liquid with the odor of rubbing alcohol, and lists these synonyms: dimethyl carbinol, IPA, isopropanol, 2-propanol, sec-propyl alcohol and “rubbing alcohol”.
In healthcare, the US Centers for Disease Control and Prevention (CDC) describes alcohols as disinfectants used mainly on small surfaces and certain pieces of equipment. They are not recommended for sterilizing medical and surgical materials.
Is isopropyl alcohol the same as rubbing alcohol?
Largely yes as a name: NIOSH lists “rubbing alcohol” as a synonym for isopropyl alcohol under CAS 67-63-0. A bottle sold as rubbing alcohol is a product, though, and the strength and ingredients are set by the label. Read the label and the safety data sheet for the exact product rather than assuming the name tells you the concentration. For the specific swab format used before injections, see what an alcohol swab is.
Uses
CDC identifies the main disinfection use of alcohols as small surfaces and certain equipment. CDC also notes limits that decide whether it is the right tool:
- Alcohols do not destroy bacterial spores.
- They are not recommended for sterilizing medical and surgical materials.
- They evaporate quickly, so extended contact time is hard to achieve unless items are immersed.
- Isopropyl alcohol is fully active against lipid viruses but not active against the nonlipid enteroviruses.
For its place in skin preparation before an injection, see skin antisepsis before injection.
Isopropyl alcohol concentration: what 60-90% means, and 91% vs 99%
CDC states that the optimum bactericidal concentration of alcohols is 60%-90% solutions in water (volume/volume), and that activity drops sharply when the alcohol is diluted below 50%.
| Concentration (v/v in water) | What CDC says |
|---|---|
| 60%-90% | Optimum bactericidal concentration range |
| Below 50% | Activity drops sharply |
| Above 90% (for example labels reading 91% or 99%) | Outside the 60%-90% range CDC gives as optimum |
Isopropyl alcohol 91% vs 99%
Both strengths sit above the 60%-90% range that CDC gives for disinfection, so a higher number on the bottle does not mean stronger disinfection. If a product is bought for disinfecting, compare its labeled strength with that range and with the manufacturer’s directions. For any other use, follow the product’s instructions for use and safety data sheet.
Properties and hazards
These values come from the NIOSH Pocket Guide entry for isopropyl alcohol (checked 2026-10-29).
| Property | Value (NIOSH) |
|---|---|
| Boiling point | 181 F |
| Flash point | 53 F |
| Flammable limits | LEL 2.0%, UEL 12.7% (at 200 F) |
| Solubility | Miscible |
| NIOSH recommended exposure limit | TWA 400 ppm (980 mg/m3); short-term 500 ppm (1225 mg/m3) |
| OSHA permissible exposure limit | TWA 400 ppm |
A flash point of 53 F is below ordinary room temperature, so flammability controls matter. NIOSH lists a recommended exposure limit (REL) and OSHA lists a permissible exposure limit (PEL); check which limit applies to your workplace. See also the chemical safety software entry for tracking safety data sheets.
Safe use and handling basics
- CDC: alcohols are flammable and must be stored in a cool, well-ventilated area.
- CDC: prolonged and repeated use can swell or harden rubber and some plastic tubing and damage shellac mountings on lensed instruments.
- Read the product’s safety data sheet for the exact product; gloves and other protective equipment depend on it, as covered in the glove compatibility chart entry.
- For wider laboratory storage rules, see oxidizer storage requirements in the laboratory.
Common mistakes
- Assuming a higher percentage disinfects better. CDC’s optimum range is 60%-90%, and activity falls below 50%.
- Using it to sterilize. CDC says alcohols do not destroy bacterial spores and are not recommended for sterilizing medical and surgical materials.
- Expecting a quick wipe to give long contact. It evaporates quickly, so contact time can be too short.
- Using it on every virus. It is fully active against lipid viruses but not against nonlipid enteroviruses.
- Storing it warm or unventilated. It is flammable; CDC calls for a cool, well-ventilated area.
FAQ
What is isopropyl alcohol?
A colorless, flammable liquid (CAS 67-63-0) also called isopropanol, 2-propanol or IPA, used as a disinfectant on small surfaces and certain equipment.
Is isopropyl alcohol the same as rubbing alcohol?
NIOSH lists “rubbing alcohol” as a synonym of isopropyl alcohol. The exact strength of a given bottle is shown on its label.
What is isopropyl alcohol 91 vs 99?
They are two labeled strengths, both above the 60%-90% range CDC gives as optimum for bactericidal activity.
What concentration of isopropyl alcohol disinfects?
CDC gives 60%-90% in water (volume/volume) as the optimum bactericidal concentration, with activity dropping sharply below 50%.
Does isopropyl alcohol sterilize equipment?
No. CDC says alcohols do not destroy bacterial spores and are not recommended for sterilizing medical and surgical materials.
Sources
- NIOSH Pocket Guide to Chemical Hazards, Isopropyl alcohol: cdc.gov/niosh/npg/npgd0359.html (date checked: 2026-10-29).
- CDC, Chemical Disinfectants (Disinfection and Sterilization guideline): cdc.gov chemical disinfectants (date checked: 2026-10-29).
