Written and maintained by CASRAI Editorial Board
Last updated
Isopropyl alcohol disposal depends on the waste’s strength and on the rules that apply where you are. Neat or high-strength isopropyl alcohol is an ignitable liquid under US federal hazardous waste rules (waste code D001), so it is collected as hazardous waste rather than poured away. A dilute water-based solution can fall outside that one federal test, but that is not permission to use the drain. The product’s safety data sheet (SDS), section 13, and your local waste rules decide the actual route. This page is general information for lab, clinic and supply staff, not compliance advice for a specific site.
Short answer
Treat isopropyl alcohol waste as ignitable until the facts say otherwise. Its flash point is 53 F, well below the 140 F (60 C) line in the federal ignitability test, so waste isopropyl alcohol of ordinary strength is ignitable hazardous waste (D001). Only a solution containing less than 24 percent alcohol by volume and at least 50 percent water by weight is excluded from that particular test. Other characteristics, your SDS and local rules still apply.
Definition and scope
EPA describes hazardous waste as waste with properties that make it dangerous or capable of having a harmful effect on human health or the environment. Ignitability is one of the properties a waste can have. For isopropyl alcohol, ignitability is the property that matters most, and it is the one this page covers. Other hazards that a mixed waste carries (for example, from whatever was dissolved in it) are outside what the flash-point test measures; see the guide on hazardous waste determination and the list of RCRA hazardous waste codes.
For what the chemical is and how it is used as a disinfectant, see what isopropyl alcohol is and 70% isopropyl alcohol as a disinfectant. This page is only about what happens to it afterwards.
Why neat isopropyl alcohol is ignitable waste
Under 40 CFR 261.21, a liquid is ignitable if it has a flash point less than 60 C (140 F). Ignitable waste is assigned hazardous waste number D001. The NIOSH Pocket Guide lists isopropyl alcohol with a flash point of 53 F, a lower explosive limit of 2.0 percent and an upper explosive limit of 12.7 percent (at 200 F), and classes it as a Class IB flammable liquid, defined as a flash point below 73 F with a boiling point at or above 100 F.
| Figure | Value | Source |
|---|---|---|
| Federal ignitability threshold (liquids) | Flash point below 60 C (140 F) | 40 CFR 261.21 |
| Isopropyl alcohol flash point | 53 F | NIOSH Pocket Guide |
| Flammable range in air | 2.0% (LEL) to 12.7% (UEL, at 200 F) | NIOSH Pocket Guide |
| Flammability class | Class IB flammable liquid | NIOSH Pocket Guide |
| Waste number for ignitable waste | D001 | 40 CFR 261.21 |
Because 53 F is far below 140 F, the comparison is not close. Neat isopropyl alcohol and waste of similar strength meet the ignitability test.
Where the 24 percent alcohol line comes in
The same regulation excludes “a solution containing less than 24 percent alcohol by volume and at least 50 percent water by weight” from the liquid ignitability test. Two conditions must both hold: the alcohol content is under 24 percent by volume, and water is at least half the solution by weight.
What the exclusion does not say matters as much. It removes one characteristic (ignitability by the liquid test). It does not say the solution is non-hazardous for other reasons, and it does not say a sewer authority will accept it. Whether a waste may go to the drain is a separate question answered by your SDS, your local wastewater authority and your institution’s waste program.
How disposal information is supposed to reach you
OSHA’s Hazard Communication Standard (29 CFR 1910.1200, Appendix D) sets out the sections of a safety data sheet. Section 13, Disposal considerations, asks for a description of waste residues and information on their safe handling and methods of disposal, including disposal of any contaminated packaging. OSHA treats the content of this section as non-mandatory, so it can be brief. It is where to start, not where to stop: pair it with your hazardous waste determination and the local rules that apply to your site.
Related products: what decides each one
People searching for isopropyl alcohol disposal often need the same answer for neighbouring products. This page makes no product-specific disposal claim beyond isopropyl alcohol; for each product below, the deciding documents are the same.
| Product | First place to look | Also check |
|---|---|---|
| Hydrogen peroxide | The product’s SDS, section 13 | Your hazardous waste determination; local wastewater rules |
| Bleach | The product’s SDS, section 13 | Your hazardous waste determination; local wastewater rules |
| Hand sanitizer | The label and SDS, for the alcohol content and flash point | The same 261.21 test applied to the waste liquid; local rules |
| Ethyl alcohol | The SDS flash point and alcohol percentage | The same 261.21 test and 24 percent exclusion; local rules |
| Biohazard bags | Your biohazard waste plan; see biohazard bag and container requirements | Local medical waste rules |
| Glutaraldehyde | The product’s SDS, section 13 | Your hazardous waste determination; local wastewater rules |
For why incompatible chemicals should not share a waste container, see chemical storage compatibility and segregation rules.
Common misunderstandings
“70% rubbing alcohol is under 24%, so it can go down the drain.”
No. 70 percent is well above the 24 percent line, so the exclusion does not apply to it. And even where a solution is under 24 percent, the line is a federal characteristic test for ignitability, not a drain permission.
“If it is not ignitable it is not regulated.”
Ignitability is one characteristic. A waste is judged on all its properties, including what else is in it.
“The SDS will give a full procedure.”
Section 13 is non-mandatory content in the OSHA standard and may be short. Treat it as a pointer to your site’s waste program.
FAQ
Is isopropyl alcohol hazardous waste?
At ordinary strength, yes for ignitability: its 53 F flash point is below the 140 F threshold in 40 CFR 261.21, and ignitable waste is coded D001.
Does a dilute solution count as hazardous waste?
A solution with under 24 percent alcohol by volume and at least 50 percent water by weight is excluded from the liquid ignitability test. Other characteristics and local rules still apply.
Where do I find the disposal instructions for a product?
In section 13 of its safety data sheet, then in your institution’s hazardous waste program and local rules.
Does this apply to hand sanitizer, ethyl alcohol, bleach, hydrogen peroxide, glutaraldehyde or biohazard bags?
Each has its own SDS and waste route. The table above shows what decides each; this page states the isopropyl alcohol facts only.
Sources
- US EPA / eCFR text of 40 CFR 261.21, Characteristic of ignitability (Cornell LII copy): law.cornell.edu/cfr/text/40/261.21. Checked 2026-10-30.
- CDC NIOSH Pocket Guide to Chemical Hazards, isopropyl alcohol: cdc.gov/niosh/npg/npgd0359.html. Checked 2026-10-30.
- OSHA, 29 CFR 1910.1200 Appendix D, Safety Data Sheets (section 13): osha.gov/laws-regs/regulations/standardnumber/1910/1910.1200AppD. Checked 2026-10-30.
- US EPA, Learn the Basics of Hazardous Waste: epa.gov/hw/learn-basics-hazardous-waste. Checked 2026-10-30.
