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ECAR Fact Sheet for Colorado

Self-Audit Checklist
Best Management Practices
Related ECAR Fact Sheets
Other Relevant Resources


The following fact sheet was prepared by the ECAR Center staff. Once prepared, each ECAR Center fact sheet undergoes a review process with the applicable state environmental agency(ies). You can check on the status of the review process here. Please read the disclaimer on the status page. While we have tried to present a summary of the essential information on this topic, you should be aware that other items, such as local regulations, may apply to you.

What You Need to Know

State Manuals/

Compliance Bulletin Hazardous Waste - Used Antifreeze

Antifreeze is used as an engine coolant and contains ethylene glycol or propylene glycol. Ethylene glycol is very toxic and is attractive to animals and small

children due to its sweet taste. Propylene glycol is significantly less toxic and has an acrid taste. Both of these products have a lime green color. Some vehicle manufacturers are now using an extended-life engine coolant that is orange colored and has a recommended service change interval of five years/100,000 miles.

The green coolants should never be mixed with the orange coolant, even in tiny amounts, or the extended life benefits of the orange coolant are lost.

The Colorado Department of Public Health and Environment (CDPHE) has prepared a guidance document to help auto recyclers manage used antifreeze. Much of that information is included in the fact sheet below. You can access the link to the CDPHE's Used Antifreeze Compliance Bulletin under Other Relevant Resources.


Waste Classification. Waste antifreeze is not a listed hazardous waste under the federal hazardous waste regulations. However, it may be a hazardous waste depending on the contaminants it has picked up. The test used to find out if used antifreeze is a hazardous waste is called the Toxicity Characteristic Leaching Procedure (TCLP).

If your used antifreeze is determined to be a hazardous waste, you must manage it according to the hazardous waste rules. Listed below are the proper management requirements or see the ECAR Hazardous Waste Fact Sheet for more detailed information.

  • Label all containers in accordance with the hazardous waste rules. Remember to clearly mark the words "WASTE ANTIFREEZE - HAZARDOUS WASTE."
  • Keep storage containers closed to prevent evaporation and spills.
  • Use only permitted waste transporters that have obtained an EPA identification number to transport drums of antifreeze off site.
  • Keep a copy of the test results and manifests for off-site disposal in your files.
  • Manage the residue or filter cartridge as a hazardous waste.

Recycling.  Acceptable methods of managing used antifreeze include recycling, disposal at a hazardous waste treatment, storage, or disposal facility (TSDF), or discharge to a wastewater treatment plant with prior written approval of the Publicly Owned Treatment Works (POTW). Most wastewater treatment plants discourage sewering of used antifreeze, and many no longer allow discharges of antifreeze to their systems at all.

Antifreeze may be recycled by distillation, ion exchange, or filtration. Distillation and ion exchange restore the antifreeze to a high level of purity. Mechanical filtration may remove undissolved solids, but may not remove contaminants dissolved in the antifreeze. Mechanical filtration combined with other technologies, such as chemical filtration (which precipitates heavy metals out of used antifreeze), can be very effective in removing contaminants. After recycling, the antifreeze should be chemically refortified with rust and corrosion inhibitors, acid neutralizers, clogging and foaming agents, and pH buffers. Some major vehicle manufacturers allow recycled antifreeze meeting specific criteria to be used in vehicles under warranty. Check with vehicle manufacturers for further information. Used antifreeze should not be mixed with used oil as the mixture is not easily recycled.

Generators may recycle their own used antifreeze in any of several commercially available onsite recycling units. Alternatively, the generator may have his used antifreeze handled by a legitimate recycler. Many used oil recyclers also pick up used antifreeze for recycling. The recycler may recycle the used antifreeze at the generator's facility or may transport it to a recycling facility for reclamation. A hazardous waste determination must be made on all wastes produced by the recycling process, such as filters and sludges, and these wastes managed appropriately. Such wastes contain concentrated heavy metals and other contaminants removed from the antifreeze.

Although the recycling process does not require a treatment permit, the owner or operator of a facility that recycles contaminated antifreeze without storing it before it is recycled must notify the state of their hazardous waste activity and must utilize the manifest system. If the recycler stores used antifreeze that exhibits one or more characteristics of hazardous waste longer than 24 hours before recycling, the recycler must also obtain a hazardous waste storage permit.

Spills. When a chemical spill or release occurs in Colorado, there are a number of reporting and notification requirements that must be followed by the agency or individual responsible for the spill.   These requirements tend to be confusing, and regulations often overlap.

At minimum, notify the Colorado 24-hour Emergency Spill/Release Reporting Line at 877-518-5608 and the Local Emergency Planning Committee at 303-273-1622, immediately or within 24-hours. Refer to the Spill Response Fact Sheet to determine your reporting requirements.

Links to the Regulations. Use the following links to view the regulations pertaining to used antifreeze management.

Colorado Hazardous Waste Management Requirements

Federal EPA Standards Applicable to Generators of Hazardous Waste

Self-Audit Checklist

When an inspector comes to your facility, there are certain things he or she checks to see if you are in compliance with environmental regulations. It makes good sense for you to perform a "self-audit" and catch and correct problems before they result in penalties. Also, there are some compliance incentives associated with self-audits (see Audit Policy Page).

Use the following list to audit your antifreeze storage areas and management procedures.

  1. Is used antifreeze stored in drums, tanks or other containers that are in good condition? Open containers, and rusting or leaking containers cannot be used for antifreeze storage.
  2. Are antifreeze storage containers and tanks properly labeled? All waste antifreeze should be labeled "Waste Antifreeze Only," and antifreeze that can be recycled or reused, should be marked "Usable Antifreeze Only."
  3. Is the area around the used antifreeze storage containers free of releases? Releases must be stopped, the released material cleaned up, managed properly, and at minimum, reported to the CDPHE and the local Emergency Planning Commission.
  4. Is used antifreeze transported to a recovery facility by a certified transporter? Check your records and verify that all shipments of used antifreeze were removed from your property by a state certified transporter.
  5. Is oil, solvent or other materials mixed with used antifreeze? Verify that there are separate, clearly labeled containers for each type of material, and that used antifreeze is not mixed with used oil, solvents and other materials.

Best Management Practices (BMPs)

Most regulations tell you what you have to do to be in compliance, but they don't explain how to do it. That's where "best management practices" come into play. BMPs are proven methods that help you to get into compliance and stay there. The following BMPs are recommended for used antifreeze storage areas and management procedures.

  • Use separate equipment for the collection of used antifreeze (funnels, pads, storage containers).
  • Drain antifreeze from radiators and heater cores as soon as possible.
  • Keep waste antifreeze free from cross-contamination with other wastes, including used oil, fuels, degreasers or radiator flush chemicals.
  • Keep antifreeze storage containers closed at all times.
  • Determine if the antifreeze is waste fluid or reusable and can be recycled.
  • Recycle by reuse, distillation, filtration or ion exchange. Recycling can be done on-site or off-site by an antifreeze recycling service.
  • Wear eye protection, clothing that covers exposed skin and rubber gloves when transferring antifreeze. Pour slowly and carefully to avoid splashing.
  • Consider keeping antifreeze in two separate, closed containers: one for antifreeze that cannot be reused marked "Waste Antifreeze," and one marked "Usable Antifreeze."
  • Do not dispose of antifreeze down storm drains (unless you have permission from your wastewater treatment plant), in septic tanks, dry wells or on bare ground.
  • Keep any records relating to used antifreeze for at least 3 years. This includes receipts for used antifreeze shipments and any laboratory results.

  1. For more information, contact the Colorado Department of Health and Environment's technical assistance line at 303-692-3320, or toll-free at 888-569-1831, if outside of the 303 area code.
  2. To report a spill or leak, at minimum, call the Colorado 24-hour Emergency Spill/Release Reporting Line at 877-518-5608 and the Local Emergency Planning Committee at 303-273-1622, immediately or within 24-hours. Refer to the Spill Response Fact Sheet to determine your reporting requirements.

Related ECAR Fact Sheets

  1. Hazardous Wastes
  2. Spill Response Fact Sheet

Other Related Resources

  1. Colorado Used Antifreeze Compliance Bulletin
  2. Colorado's Automotive Salvage Yard Waste Management Practices


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