Detailed Questions About HC-12a ®, OZ-12 ®, DURACOOL 12a ®, EC-12a, and other Flammable Hydrocarbon Refrigerants

If you have questions beyond those in this fact sheet, or would like paper copies of the lists, please call the Stratospheric Ozone Protection Hotline toll-free at 1 (800) 296-1996 or direct dial (202) 343-9210 to leave inquiries.

What are HC-12a® and OZ-12®?
What is DURACOOL 12a®? Is there a difference between HC-12a® and DURACOOL 12a®?
What is the legal status of hydrocarbon refrigerants such as HC-12a® and DURACOOL 12a®?
What is EC-12a and what is its legal status?
May hydrocarbon refrigerants be used to replace CFC-12, commonly referred to as "Freon®," in cars?
How did EPA make this determination?
Why is it legal to use hydrocarbon refrigerants as CFC-12 substitutes in industrial process refrigeration, but not elsewhere?
Gasoline and brake fluid are flammable, but they're allowed in cars. Why not hydrocarbon refrigerants?
Is the sale of hydrocarbon refrigerants legal?
Since the autoignition temperature of HFC-134a is lower than that of hydrocarbon refrigerants such as HC-12a® and DURACOOL 12a®, doesn't that mean that HFC-134a is more flammable than these hydrocarbons?
What is a "sham retrofit" of a motor vehicle A/C system?
May hydrocarbon refrigerants be vented?
What other regulations restrict the use and handling of hydrocarbon refrigerants?
Are there other refrigerants that can replace CFC-12?
Are there any advantages to using flammable hydrocarbon refrigerants?
Has EPA found any flammable refrigerants acceptable under SNAP?
Is it legal to replace HFC-134a in a motor vehicle with hydrocarbon refrigerants such as DURACOOL 12a® and HC-12a®?

What are HC-12a® and OZ-12®?
HC-12a® and OZ-12® brand hydrocarbon refrigerant blends are flammable refrigerants. Their primary components are hydrocarbons, which are flammable substances such as propane and butane. HC-12a® and OZ-12® are registered trademarks of OZ Technology, Inc. HC-12a® has been marketed since 1994. OZ-12® was a similar blend marketed until the introduction of HC-12a® . Both products have been reviewed by EPA under the Significant New Alternatives Policy (SNAP) program. More information about the SNAP program is available from the hotline listed at the top of this page.
Note that EPA refers to the chemical composition of HC-12a® as Hydrocarbon Blend B. EPA considers any substance with that chemical composition, no matter what its trade name is, to be Hydrocarbon Blend B and to have the same legal status that HC-12a® has.

In order to meet Department of Transportation requirements for shipping HC-12a® in six-ounce cans (DOT refers to these cans as DOT 2Q containers), OZ Technology reduced the vapor pressure of HC-12a® in June, 1998. In order to reduce the vapor pressure, OZ Technology changed the composition of HC-12a®. EPA does not consider this reformulated HC-12a® to be the same as Hydrocarbon Blend B. The reformulated HC-12a® has not been submitted for SNAP review, and thus cannot be marketed or used as a substitute for ozone-depleting substances.
What is DURACOOL 12a®? Is there a difference between HC-12a® and DURACOOL 12a®?
DURACOOL 12a® has the same chemical composition as the HC-12a® formulation that was submitted for SNAP review as Hydrocarbon Blend B. Both HC-12a® and DURACOOL 12a® are different than the new formulation of HC-12a® in six-ounce cans. DURACOOL 12a® is the registered trademark of Duracool Limited, the Canadian company that has manufactured DURACOOL 12a® since 1997. Duracool Limited and OZ Technology, the manufacturer of HC-12a®, are separate, unrelated companies with their own manufacturing facilities and distribution mechanisms.
What is the legal status of hydrocarbon refrigerants such as HC-12a® and DURACOOL 12a®?
It has been illegal since July 13, 1995 to replace CFC-12 with the HC-12a® formulation that was submitted for SNAP review in any refrigeration or A/C application other than industrial process refrigeration. The same prohibition for OZ-12® took effect on April 18, 1994. Because DURACOOL 12a® has the same chemical composition as the HC-12a® formulation that was submitted for SNAP review (i.e., Hydrocarbon Blend B), DURACOOL 12a® is also subject to the same restrictions.
HC-12a®, as reformulated to meet DOT requirements, is not the same as Hydrocarbon Blend B and has not been submitted for SNAP review. OZ Technology is therefore prohibited from marketing this blend as a substitute for any ozone-depleting substance. In addition, any use of this blend as a substitute for CFC-12 or any other ozone-depleting chemical, in industrial process refrigeration or any other refrigeration or A/C end use, is prohibited under the Clean Air Act.

Since HC-12a® as submitted for SNAP review, is chemically different from HC-12a®, as reformulated to meet DOT requirements, and since it has a different legal status under the Clean Air Act, users of any substance marketed as HC-12a® should be aware of which HC-12a® they have purchased.

Note that the Clean Air Act does not regulate the use of any of these hydrocarbon refrigerants when they are used as replacements for non-ozone-depleting chemicals such as HFC-134a. However, many states prohibit using flammable refrigerants in motor vehicles, regardless of which original refrigerant was used in the vehicle.
What is EC-12a and what is its legal status?
Because it has not been submitted for review under the SNAP program, EPA is not aware of EC-12a's chemical composition. EC-12a is not legal to sell or use in any refrigeration or A/C end-use as a substitute for CFC-12 or any other ozone-depleting refrigerant, because it has not been submitted for SNAP review.
May hydrocarbon refrigerants be used to replace CFC-12, commonly referred to as "Freon® ," in cars?
No. It is illegal to use hydrocarbon refrigerants like HC-12a® and DURACOOL 12a® as substitutes for CFC-12 in automobile or truck air conditioning under any circumstances.
How did EPA make this determination?
The Clean Air Act, as amended in 1990, required EPA to establish a program to review substitutes for ozone-depleting substances, including refrigerants. EPA's Significant New Alternatives Policy (SNAP) program carries out this mandate. Manufacturers of substitutes must submit information to EPA about the products, including ozone depletion potential, global warming potential, and toxicity and flammability data. EPA then compares these characteristics to both the refrigerant being replaced and the other available substitutes.
Most refrigerants submitted to EPA for review under SNAP have been found acceptable, often subject to certain conditions. A full list of alternatives is available online. In particular, several refrigerants have been listed acceptable for use as CFC-12 substitutes in motor vehicle air conditioning, subject to certain conditions on their use. Each acceptable alternative refrigerant has been demonstrated to a) be safer for human health and the environment than the original refrigerant, and b) pose a level of risk similar to that of other acceptable alternatives.

Flammable refrigerants pose a special challenge, because air conditioning and refrigeration systems in the US have been designed to use nonflammable refrigerants. They are not designed to protect users, service technicians, and disposal personnel from the possibility of fire. Therefore, the use of flammable refrigerants in existing systems may pose a risk not found with nonflammable fluids.

Although new systems may be designed to provide that protection, they are not specifically designed so today. Demonstrating that a flammable refrigerant can be used safely in current systems, whether existing or new, requires a comprehensive, detailed, scientifically valid risk assessment. EPA has required a risk assessment for flammable refrigerants since the inception of the SNAP program in 1994. An assessment must address potential leak scenarios such as collisions, servicing errors, and disposal procedures. In addition, it must consider ignition sources ranging from cigarette lighters or matches to sparks caused during a collision.

OZ Technology has submitted reports that it states demonstrate the safety of using OZ-12® and HC-12a® in systems not designed to use such flammable refrigerants. However, after careful review of each document, EPA determined that none of the reports represented valid a risk assessment. Until such assessments are performed, EPA believes that flammable refrigerants like HC-12a®, OZ-12® and DURACOOL 12a® may pose potential risks not present when using nonflammable refrigerants. For these reasons, EPA does not allow the use of HC-12a®, OZ-12® or DURACOOL 12a® as substitutes for CFC-12 outside of industrial process refrigeration. (Note that HC-12a®, as reformulated to meet DOT requirements, is not permitted to be sold or used as a substitute for ozone-depleting chemicals in industrial process refrigeration, since it has not been submitted to SNAP for review.)
Why is it legal to use hydrocarbon refrigerants as CFC-12 substitutes in industrial process refrigeration, but not elsewhere?
EPA has not yet received data that adequately address the safety issues of hydrocarbon refrigerants in applications other than industrial process refrigeration. Flammability risks depend on the type of refrigeration or air-conditioning system. Industrial process refrigeration, for instance, does not include air conditioning, which pipes refrigerated air directly into occupied areas. Industrial process refrigeration generally refers to complex customized appliances used in the chemical, pharmaceutical, petrochemical and manufacturing industries. Direct risk to human health is reduced in industrial process refrigeration; for example, access to areas near the system is typically restricted. In addition, other regulations exist to protect the safety of industrial workers.
EPA will review any additional material that is submitted under SNAP regarding the safety considerations of using hydrocarbon refrigerants in systems other than industrial process refrigeration.
Gasoline and brake fluid are flammable, but they're allowed in cars. Why not hydrocarbon refrigerants?
Because EPA has been directed by Congress, under the SNAP program, to consider the safety aspects of alternative refrigerants for CFC-12 (as well as their environmental characteristics), it is necessary to address the safety aspects of using a flammable refrigerant in motor vehicle A/C systems originally designed for CFC-12, before that refrigerant can be approved.
There are good reasons why gasoline and other fluids may be used safely while the use of hydrocarbon refrigerants in A/C systems may not be safe. Gasoline and other flammable substances are used in systems designed specifically for flammable fluids. A gas tank is deliberately placed in the middle of the rear part of a vehicle to protect it against collisions. Air conditioner condensers, in contrast, are placed at the very front of the car to maintain good air flow. Unfortunately, this location means that condensers may be punctured during a front-end collision. Another difference is that unlike gasoline lines, air conditioners include lines that provide cooling directly to occupied areas -- in this case, passenger compartments. Flammability risk is extremely dependent on the specific system being considered; the simple presence of other flammable fluids in a car does not address the safety of using hydrocarbon refrigerants in an automobile air conditioner.
Is sale of hydrocarbon refrigerants legal?
Sale of subtitute refrigerants listed under the SNAP program is not regulated under SNAP. However, statutes and regulations issued by other federal, state, or local agencies may control the sale of these products, including illegal advertising.
Since the autoignition temperature of HFC-134a is lower than that of hydrocarbon refrigerants such as HC-12a® and DURACOOL 12a®, doesn't that mean that HFC-134a is more flammable than these hydrocarbons?
According to both Underwriters Laboratories and the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE), the main standard-setting body for refrigerants in the U.S., hydrocarbons are flammable materials. Flammability, as defined by the American Society for Testing Materials (ASTM) E-681 standard test procedure for refrigerants, means that a substance will ignite at atmospheric pressure when mixed in some concentration in air at normal temperature and pressure. The minimum and maximum concentrations at which ignition will occur are called the lower and upper flammability limits in air. Hydrocarbons, like the components of HC-12a® and DURACOOL 12a®, become flammable at concentrations as low as 2% by volume. These values are well-established in published literature.
Autoignition temperature is a distinct measure from flammability limits in air. Specifically, this test measures the temperature at which a substance will spontaneously ignite, without any external ignition source like a match or lighter.

Certain documents claim that because the autoignition temperature of HFC-134a is below 750 degrees Celsius (1382 degrees Fahrenheit), it is flammable, and because the autoignition temperature of hydrocarbon refrigerant blends such as HC-12a® is above 750 degrees Celsius, it is nonflammable. However, this statement misrepresents the procedure used by Underwriters Laboratories to classify refrigerants.

UL first examines whether a refrigerant burns in air at some concentration and normal pressure and temperature. If it does ignite under these conditions, it is classified as flammable. Hydrocarbons, like the components of HC-12a® and DURACOOL 12a®, are classified as flammable. (Note that hydrocarbon refrigerant manufacturers recognize that their products are flammable, and label containers for those products with the word "flammable.")

If a refrigerant is not classified as flammable as a result of this test procedure, UL then uses the autoignition temperature to distinguish between practically nonflammable refrigerants (meaning the autoignition temperature is below 750 degrees Celsius) and nonflammable refrigerants (meaning the autoignition temperature is above 750 degrees Celsius). HFC-134a does not ignite, regardless of concentration, at atmospheric temperatures and pressures. This means that at atmospheric pressures and temperatures, if a can of HFC-134a is opened and a lit match is placed in front of the can, the HFC-134a will extinguish the match. HFC-134a is classified by UL as practically nonflammable because its autoignition temperature is below 750 Celsius. Note that UL lists most alternative refrigerants as practically nonflammable. HCFC-22, the refrigerant used in most home air-conditioning, is also classified as practically non-flammable.
What is a "sham retrofit" of a motor vehicle A/C system?
EPA does not regulate the use of hydrocarbon refrigerants such as HC-12a® and DURACOOL 12a® as substitutes for HFC-134a in motor vehicles. Certain materials have circulated claiming that by first converting a system from CFC-12 to HFC-134a, the system may then be converted to use a hydrocarbon refrigerant without violating the original prohibition against using hydrocarbons as substitutes for CFC-12. Thus, the question arises about the definition of a legitimate retrofit. This definition hinges on two distinct principles: complying with the conditions placed on using HFC-134a under the SNAP program, and the intent of the retrofit.
In accordance with the SNAP rules, a retrofit from CFC-12 to HFC-134a must meet certain requirements. The CFC-12 must be completely recovered in accordance with regulations issued under section 609 of the Clean Air Act. Fittings designed for use with HFC-134a must be permanently attached to the system. These fittings mechanically prevent the mixing of HFC-134a with CFC-12 and other refrigerants. Finally, the system must be labeled, and the label must contain detailed information as described by the SNAP rule. Some vehicles also require the installation of a compressor shutoff switch. Performing these activities complies with the letter of the SNAP regulations.

Even such compliance may not, however, indicate a legitimate retrofit. For example, HFC-134a should be used with a different lubricating oil from CFC-12; if the lubricant is not changed, the air conditioner will not work. Similarly, a vehicle must be charged with the correct amount of HFC-134a in order for the air conditioner to work. Failure to take these steps indicates that the technician does not truly intend to convert the vehicle's air conditioner to work with HFC-134a, and the subsequent installation of a hydrocarbon refrigerant such as HC-12a® or DURACOOL 12a® may violate the prohibition against using hydrocarbon refrigerants as CFC-12 substitutes.

Other indications of a sham retrofit also exist, including the timing of the retrofit. In general, if a car arrives in a repair shop containing CFC-12 and leaves containing a hydrocarbon refrigerant, it is likely that it underwent a sham retrofit, regardless of what actually occurred in the shop. Generally, if HFC-134a is charged into a system and then immediately removed, such a temporary retrofit to HFC-134a was likely intended solely to allow the use of HC-12a®, DURACOOL 12a®, or other hydrocarbon refrigerant in a car designed to use CFC-12. EPA is currently investigating several complaints, and believes indications such as those described above support finding a Clean Air Act violation.
May hydrocarbon refrigerants be vented?
No. The Clean Air Act prohibits the venting of any refrigerant during the service, maintenance, repair, or disposal of air conditioning and refrigeration systems. When working on a system containing a hydrocarbon refrigerant such as HC-12a® or DURACOOL 12a®, the technician must recover the refrigerant into a suitable container and safely dispose of it.
What other regulations restrict the use and handling of hydrocarbon refrigerants?
In addition to the prohibition on use described above, and the federal law banning the venting of all refrigerants, there are also state and local statutes and regulations that relate to certain uses of hydrocarbons. As of the printing date of this fact sheet, EPA is aware that the following states prohibit the use of flammable refrigerants in automobile air conditioners: Arkansas, Arizona, Connecticut, Florida, Idaho, Indiana, Iowa, Kansas, Louisiana, Maryland, Nebraska, North Dakota, Oklahoma, Texas, Utah, Virginia, Washington, Wisconsin, and the District of Columbia.

Local fire codes also often restrict the storage of flammable materials. In addition, other federal, state, and local regulatory agencies may have regulations related to flammable refrigerants. Check with these authorities for more information.
Are there other refrigerants that can replace CFC-12?
Yes. Lists of alternatives in other sectors are available online and from our hotline at 800-296-1996. In addition, the fact sheet titled "Choosing and Using Alternative Refrigerants for Motor Vehicle Air Conditioning" lists all SNAP-reviewed motor vehicle refrigerants and conditions on the use of those listed as acceptable.
Are there any advantages to using flammable hydrocarbon refrigerants?
Many flammable refrigerants offer potential energy efficiency savings, lower global warming potentials, low toxicity, and low cost. EPA believes that, with responsible development, flammable refrigerants have a role to play in the transition away from ozone-depleting substances. However, such development must adequately address safety concerns associated with manufacturing, use, servicing, and disposal of these new products. EPA is aware of several successful uses of flammable refrigerants, and welcomes future development of systems designed to be used with them.
The primary drawback to the use of flammable refrigerants today is that most existing systems are not designed to protect people from that flammability. In order to find a flammable refrigerant acceptable, EPA requires the completion of a risk assessment to determine the additional hazard posed by that flammability and necessary steps to mitigate any additional hazard. EPA believes hydrocarbons and other flammable refrigerants offer the potential to be good substitutes for ozone-depleting refrigerants. The best possibilities exist in the design of new equipment that includes safety features to protect against a fire or explosion. Several such systems are now being sold and developed around the world. EPA has always encouraged U.S. businesses to consider using hydrocarbon refrigerants in such newly designed systems.
Has EPA found any flammable refrigerants acceptable under SNAP?
EPA found the flammable refrigerant HFC-152a acceptable for use in new household refrigerators and freezers. This determination was based on a detailed assessment of the risks posed by this flammable refrigerant in this particular application. Note that HFC-152a, which is a single chemical rather than a blend, is not a hydrocarbon. The fact that HFC-152a was found acceptable in refrigerators cannot be read as encompassing all hydrocarbon or other flammable refrigerants in all end-uses. A risk assessment relates only to the specific end-use and refrigerant.
Is it legal to replace HFC-134a in a motor vehicle with hydrocarbon refrigerants such as DURACOOL 12a® and HC-12a®?
In certain circumstances, the replacement of HFC-134a in a motor vehicle with hydrocarbon refrigerants might be permitted. At a minimum, in order to avoid violating the Clean Air Act, the motor vehicle A/C system must have either been originally designed for use with HFC-134a refrigerant, or must have been previously retrofitted from CFC-12 to HFC-134a refrigerant, AND no sham retrofit must have occurred to convert the system to the hydrocarbon refrigerant. In order to avoid violating other laws, the replacement of the refrigerant must not violate any state or local prohibition on the use of flammable refrigerants in motor vehicle A/C systems.
The following 19 states ban the use of flammable refrigerants such as HC-12a® and DURACOOL 12a® in motor vehicle air conditioning, regardless of the original refrigerant: Arkansas, Arizona, Connecticut, Florida, Idaho, Indiana, Iowa, Kansas, Louisiana, Maryland, Nebraska, North Dakota, Oklahoma, Texas, Utah, Virginia, Wisconsin, Washington, and the District of Columbia.

EPA and hotline staff will not, based solely on facts given in a phone call or letter, determine the legality under the SNAP program of using a hydrocarbon refrigerant in a motor vehicle retrofitted to use HFC-134a, because the determination depends on many factors, including the nature of the retrofit from CFC-12 to HFC-134a, the reason for the retrofit, and the exact procedure and timing involved.

If you plan to change a car from HFC-134a to a hydrocarbon refrigerant such as HC-12a® and DURACOOL 12a®, you should consider that auto manufacturers have stated that changing the refrigerant in new vehicles designed for use with HFC-134a will void the warranty and may damage the system. If the air conditioner on a new car or truck is not working, consult a qualified mechanic or your dealer.

Detailed Questions About HC-12a ®, OZ-12 ®, DURACOOL 12a ®, EC-12a, and other Flammable Hydrocarbon Refrigerants

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