information in this report is copyrighted to Colorado Recycles, and
is provided as a public service, it may be used with proper attribution
||Original Version: December, 2003
For a PDF version of this report, click here: Antifreeze
A Wonderful, But Hazardous, Product
Disposing of Antifreeze
Reclaiming/Recycling Used Antifreeze
Finding Recycling Resources
is a motorized and mechanized society, and Americans operate their
vehicles and equipment
in all kinds of weather, seasons and climates.
In the early days of the automobile, motorists drove vehicles that did
not have heaters or side windows. Needless to say, driving in inclement
weather – particularly in the winter – could be extremely
unpleasant. Not only were the driving conditions unpleasant and uncomfortable,
the vehicle could be particularly hard to start in cold weather. Eventually,
heaters and side windows were added, and operating or riding in the vehicle
became less uncomfortable.
Technological innovation in lubricants and engine antifreeze and coolants
progressed rapidly. These products made the operation of the vehicle
in extreme weather more feasible. Early versions of antifreeze were water
with such additives as honey, sugar, molasses, or other sugar type ingredients.
However, the most popular additive was methyl alcohol. Although the methyl
alcohol had much better performance and reliability than the other products,
it was prone to boiling away, it had an odor and it was flammable. Even
though the performance was better, drivers still faced a considerable
amount of unpredictability about the ability of the car to start and
operate in the cold.
As technology progressed, so did the ability to blend antifreeze/coolants.
They are still made predominantly of water, but the additive now is primarily
ethylene glycol or propylene glycol. Ethylene glycol and propylene glycol
have the ability to lower the freezing point of water while at the same
time raising its boiling point. This allows the vehicle to operate without
freezing on very cold days and without boiling over on very hot days.
Ethylene glycol is the most widely used automotive cooling-system antifreeze,
although methanol, ethanol, isopropyl alcohol, and propylene glycol are
In automotive windshield-washer fluids, an alcohol (e.g., methanol) is
usually added to keep the mixture from freezing; it also acts as a solvent
to help clean the glass. The brine used in some commercial refrigeration
systems is an antifreeze mixture, and is ordinarily a water solution
of calcium chloride or propylene glycol.
In recent years, antifreezes designed for different applications have
been developed and can often be distinguished by color. Green and orange
antifreeze are engine coolants for vehicles and other machines, while
pink antifreeze is often used to prevent freezing in pipes or plumbing
A Wonderful, But Hazardous, Product
Antifreeze is hazardous. Ethylene glycol is a toxic chemical that requires
proper handling, storage and disposal to avoid harming humans, animals
and the environment. One of the properties of ethylene glycol is that
it is a sweet-tasting liquid which makes it attractive to animals and
small children. Unfortunately, it is very poisonous and each year thousands
of dogs, cats and other animals die from lapping up pools of antifreeze
that have accumulated on streets and in parking areas. There have been
many cases of human poisonings and deaths over the years, predominantly
among small children. The Centers for Diseases Control and Prevention
provides a considerable amount of useful information about poisonings
and poisoning prevention on its website at http://www.cdc.gov/ncipc/factsheets/poisoning.htm .
As a broad generalization, orange colored antifreeze is an indication
that the antifreeze is manufactured for more extended uses, and has a
longer service life than does green antifreeze. However, under no circumstances
should green and orange antifreezes be mixed together because the enhanced
properties of the orange antifreeze will be diminished.
Used antifreeze may also contain levels of dissolved heavy metals that
can be toxic to animal life and may contaminate soils, water and sediments.
If ethylene glycol biodegrades in large quantities, it can deplete the
levels of dissolved oxygen in surface waters, killing aquatic organisms.
Antifreeze picks up many contaminants from engine operation in addition
to some heavy metals. It will also pick up toxins such as benzene. That
is why antifreeze must be tested to determine whether or not it falls
under the classification as being a hazardous waste.
There are some new antifreeze products on the market which purport to
be environmentally safe and to be free of the common risks of antifreeze.
While we note that the products are available, we did not search for
nor encounter any independent analyses or verifications of the claims.
If you are shopping for such products, we encourage you to research beyond
the manufacturer statements to determine whether the claims have been
Based upon our research, it appears that these “safe” alternatives
are the ones manufactured with propylene glycol rather than ethylene
glycol. Propylene glycol is not as immediately poisonous as is ethylene
glycol, nor does it have a sweet taste that makes it attractive to children
and animals. However, propylene glycol is also hazardous even if it is
less hazardous than ethylene glycol. As noted previously, all antifreeze
will absorb contaminants while it is in the cooling system, and some
of these contaminants, such as lead or chromium, are highly hazardous
in their own right.
If an antifreeze spill or leak occurs, it should be cleaned up immediately.
This can be done by spreading an absorbent material such as kitty litter
or saw dust on top of the antifreeze. Once absorbed, it can be swept
up and disposed of properly.
Disposing of Antifreeze
The best solution for disposing of antifreeze is full use or reuse.
In many cases, individuals find containers with antifreeze still in them,
and use it to top off cooling systems. If the antifreeze is still usable
and in good condition, it can be used since antifreeze stores well for
a long period of time. If the antifreeze cannot be used, give it to friends,
family, neighbors or other potential users. When the antifreeze is in
a container or a cooling system, it is not a likely pollutant or health
As we did our research for this discussion paper, we became concerned
that there were a number of seemingly conflicting recommendations from
equally credible experts and sources. While all agree that antifreeze
should never be dumped on the ground or down storm drains, there were
mixed recommendations about diluting and pouring old antifreeze (in very
small quantities) down a sink drain. Some experts recommend against the
practice entirely, while others held that small highly diluted quantities
can be handled by municipal sewer treatment systems. However, even though
antifreeze is biodegradable over time, this dilute and dispose opinion
does not extend to household septic sewer systems. Home septic systems
are bacteria driven systems that are confined to small areas and small
amounts of waste. Antifreeze could harm the bacteria that process the
wastes and impair the proper functioning of the septic system.
Because of the uncertainty, it is the strong recommendation of Colorado
Recycles that you should check directly with the operators of the municipal
sewer system for guidance and approval before considering pouring any
amount of antifreeze, no matter how diluted it may be, down the sink
drain. Colorado Recycles recommends that you assume that the wastewater
treatment facility prohibits the disposal of antifreeze into its system
until you have confirmed directly from the operator that such a disposal
Under no circumstances should antifreeze ever be poured on the ground,
in gutters, in storm drains, or in sanitary sewers. It is an almost absolute
certainty that antifreeze will pollute the aquifers, streams and bodies
of water that it comes in contact with. Nor should antifreeze be disposed
of in the trash. Waste haulers will not accept it under most circumstances,
and landfills operators will not allow liquid antifreeze to be deposited
in the landfill because compacting will damage the container and cause
the antifreeze to leak into the landfill, its leachate and into aquifers.
Antifreeze would be considered hazardous waste if it is mixed with a
hazardous waste (such as gasoline, motor oil or various solvents). Antifreeze
could be hazardous if it comes from an older vehicle where the antifreeze
has been sitting for years and has picked up enough metals (primarily
lead) to be characteristically hazardous for metals content. If the antifreeze
is determined to be a hazardous waste, it must be managed in accordance
with all hazardous waste notification, generation and transportation
requirements, laws and regulations. If there is any question at all whether
the antifreeze would be considered a hazardous waste, check directly
with the Colorado Department of Public Health and Environment for a determination
It should go without saying that antifreeze, whether new or used, should
never be stored in open containers that might be easily accessed by children
or animals. And, antifreeze should never be collected in containers that
have been used to hold other substances (such as oil or gasoline) unless
the container has been thoroughly cleaned so that no harmful substances
can leach from the sides of the container into the antifreeze. All containers
that contain antifreeze should be labeled so that individuals know that
the product is potentially hazardous. And, containers that could be mistaken
by children for food or drink products should never be used.
Leftover, unused, antifreeze should be stored in its original container
because the container and lid were designed for safe storage. The container
also has a label that will clearly indicate what the product is, its
hazards and its proper handling.
Reclaiming/Recycling Used Antifreeze
About 12 percent of all antifreeze produced in the United States is
recycled each year, and that amount is increasing.
There are essentially three strategies for recycling antifreeze that
can be used: on-site recycling, mobile recycling services, and off-site
recycling. Under most circumstances, these strategies are more applicable
to larger users (i.e., fleet operations or vehicle repair and service
operations) than to household or “do-it-yourself” activities.
On-site recycling occurs when the operator channels all the waste antifreeze
into units purchased or leased by the facility, and which are located
on the premises, and are operated by the personnel of the facility.
Mobile-recycling services exist to make periodic visits to a facility
and use specially designed or equipped vans or trucks to collect the
waste antifreeze and recycle it while still on the site.
Off-site recycling services exist to collect and transport waste antifreeze
to a specialized facility for the recycling of the antifreeze. Very often
these services will supply the customer with replacement supplies of
new or recycled antifreeze.
For the small user, household and “do-it-yourselfer”, disposing
of used antifreeze at an established household hazardous waste facility
or through a community household hazardous waste collection or roundup
event is likely to be the most feasible alternative. Some automotive
service operations will accept antifreeze for recycling from customers
as part of the service provided. Some will accept small amounts from
the public and may charge a small fee for the disposal.
Recycling used antifreeze makes sense for two reasons: first, it is cost-effective,
and second, it saves resources. Ethylene glycol, the primary active ingredient
in antifreeze, is produced from natural gas, which is a finite, non-renewable
resource. For businesses that use a lot of antifreeze, like automobile
repair shops, setting up an antifreeze recycling program can significantly
reduce management costs and decrease the amount of new materials purchased.
Using commonly available technology, these businesses can recycle antifreeze
on site and recondition it with additives at a cost that is significantly
lower than the cost of purchasing new antifreeze.
All antifreeze recycling involves two steps:
*Removing contaminants such as emulsified oils and heavy metals either
by filtration, distillation, reverse osmosis, or ion exchange. Distillation
and ion exchange systems restore the antifreeze to a high level of purity.
Filtration may remove undissolved sold contaminants, but may not capture
those that are dissolved. For that reason, mechanical filtration systems
are often combined with chemical filtration to have a more complete impact
on the contaminants.
*Restoring critical antifreeze properties with additives. Additives typically
contain chemicals that raise and stabilize pH, inhibit rust and corrosion,
reduce water scaling, and slow the breakdown of ethylene glycol.
Conventional antifreeze lasts only 2 or 3 years. The new extended-life
coolants represent a major advancement over the more conventional coolants
and greatly reduce the need to purchase new antifreeze. Different chemicals
in the antifreeze made with extended-life coolants allow it to last 5
years or 150,000 miles. Heavy-duty, extended-life antifreeze lasts between
400,000 and 600,000 miles with the use of a one-time extender. Manufacturers
expect that over the coming years, this technology will replace conventional
antifreeze and become the industry standard.
The acceptance of recycled antifreeze for the purposes of warranty coverage
may vary with manufacturer and type of vehicle. Some of the major manufacturers
will recognize the use of recycled antifreeze as being consistent with
warranty requirements. However, the manufacturer and dealer should be
contacted to make certain that the use of recycled antifreeze is approved.
Many Colorado counties and municipalities sponsor household hazardous
waste collection centers and roundup events. The Colorado Department
of Public Health and Environment maintains a current list of scheduled
roundup events on its website at http://www.cdphe.state.co.us/hm/hmhom.asp . To access this data base directly, please use the following link: Household
Hazardous Waste Collection Events at http://www.cdphe.state.co.us/hm/hhwcollect.asp .
Recycles maintains a list of antifreeze recyclers as part of our Recycling
Go to our website at www.colorado-recycles.org and
click on Recycling Guide on the menu bar. On the pull down menu for products
and materials, click on “antifreeze”. On the county pull
down menu, click on the county for which you would like to see the listings.