Basic Information

Section 612(c) of the Clean Air Act (CAA) requires the Agency to publish a list of acceptable and unacceptable substitutes for ozone-depleting substances (ODS). The SNAP program does not require that substitutes be risk- free to be found acceptable. The Agency interprets Section 612 as a mandate to identify substitutes that reduce risks compared to use of class I or II compounds and other substitutes for class I or class II substances, rather than mandate to list as acceptable only those substitutes that are risk free.

How do the SNAP listings work?

What is the difference between a rule and a notice?

Who Should Notify EPA if They Have an Alternative?

What Are the Guiding Principles of the SNAP Program?

What Are EPA's Criteria for Evaluating Alternatives?

How do the SNAP listings work?

EPA's listing decisions for substitutes fall in the following industrial sectors: Refrigeration and air conditioning, foam blowing, solvents cleaning, fire suppression and explosion protection, sterilants, aerosols, tobacco expansion and adhesives, coatings and inks. The following are EPA's classifications of decisions on alternative substitutes:

• Acceptable alternatives are determined to reduce overall risk to human health and the environment. These alternatives may be used without restriction in specific end-uses.
• Acceptable subject to use conditions means that a substitute is acceptable only if used in a certain way. For example, substitutes for CFC-12 in automotive air conditioning systems are acceptable subject to a condition that the substitute be used with unique equipment fittings such as for cars, recovery and recycling, and refrigerant containers.
• Acceptable subject to narrowed use limits means that a substitute may be used only within certain specialized applications within a sector end-use, and may not be used for other applications within an end use or sector. For example, some alternative fire suppressants may be used as total flooding agents in normally unoccupied areas, but not in occupied areas.
• Unacceptable alternatives are prohibited because the Administration has determined the use of the substitutes pose significantly higher human health and environmental risks than those risks from either continued use of the class I substitutes themselves or from use of other available substitutes. For example, HCFC-141b must not be used for metals cleaning, electronics cleaning, or precision cleaning because of its high ozone depletion potential and the refrigerant MT-31 must not be used in air conditioning and other refrigerant uses because of its toxicity.
• Pending alternatives are those for which EPA determines an extension of the 90 day review period is necessary. A delay of the review period will not affect a manufacturer’s ability to sell a product 90 days after the agency issues a notice of completion for a submission.

Further Definitions for SNAP are found here.

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What is the difference between a rule and a notice?

In general, substitutes found acceptable without restriction will be published in a notice of acceptability. Substitutes that that are found unacceptable or acceptable subject to restrictions will go through a comment period and then be published as a rule.

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Who Should Notify EPA if They Have an Alternative?

Under Section 612(e) of the CAA, producers must notify EPA at least 90 days in advance of selling an alternative for ozone-depleting substances, with exceptions. In addition, others may petition EPA for consideration of an alternative. In either case, the interested party should fill out the SNAP Submission Form and submit it to EPA. An instruction manual for SNAP Submission Forms is available here (PDF, 24 pp., 120K)

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What Are the Guiding Principles of the SNAP Program?

• Evaluate substitutes within a comparative risk framework- The program evaluates the risk of alternative compounds compared to those of ozone-depleting compounds and the available alternatives. The environmental risk factors that are considered include ozone depletion potential, flammability, toxicity, occupational health and safety, as well as contributions to global warming and other environmental factors. There are also risk factors associated with quality of information, uncertainty of data, and economics factors including feasibility and availability.
• Do not require that substitutes be risk-free to be found acceptable- The Agency finds substitutes to be either acceptable, acceptable in restrictions, or unacceptable by the Agency. For substitutes to be found acceptable they must have a reduced risk, which is not necessarily risk free, compared to ozone depleting compounds in class I or class II.
• Restrict only those substitutes that are significantly worse- The EPA does not intend to restrict a substitute if it has only marginally greater risk than another substitute. Drawing fine distinctions concerning the acceptability of substitutes would be extremely difficult given the variability in how each substitute can be used within a specific application and the resulting uncertainties surrounding potential health and environmental effects. The Agency also does not want to intercede in the market's choice of available substitutes, unless a substitute has been proposed or is being used that is clearly more harmful to human health and the environment than other alternatives.
• Evaluate risks by use- Section 612 requires that substitutes be evaluated by use. Environmental and human health exposures can vary significantly depending on the particular application of a substitute. Thus, the risk characterizations must be designed to represent differences in the environmental and human health effects associated with diverse uses. This approach cannot, however, imply fundamental tradeoffs with respect to different types of risk to either the environment or to human health.
• Provide the regulated community with information as soon as possible- The Agency recognizes the need to provide the regulated community with information on the acceptability of various substitutes as soon as possible. Future determinations on the acceptability of new substitutes are published several times a year.
• Do not endorse products manufactured by specific companies- The Agency does not issue company-specific product endorsements. In many cases, the Agency may base its analysis on data received on individual products, but addition of a substitute to the acceptable list based on that analysis does not represent endorsement of that company's products. Generally, placement on the list merely constitutes an acknowledgement that a particular product made by a company has been found to be acceptable under SNAP.
• Defer to other environmental regulations when warranted- In some cases, EPA and other federal agencies have developed extensive regulations under other statutes or other parts of the CAA that address any potential cross- or inter-media transfers that result from the alternatives to class I and class II substances. The SNAP program will take existing regulations into account. For example, EPA considers the additional safety added by existing environmental regulations on hazardous air pollutants or hazardous waste or by existing regulations for occupational safety and health.

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What Are EPA's Criteria for Evaluating Alternatives?

EPA's evaluation of each substitute in an end-use is based on the following types of information and analyses. 40 CFR 82.178 details the specific data to be submitted:

• Atmospheric effects-

  The SNAP program considers the ozone depletion potential and 100-year integrated global warming potential of compounds to assess atmospheric effects.

  
  

• Exposure assessments-

  Exposure assessments are used to estimate concentration levels of substitutes to which workers, consumers, the general population, and environmental receptors may be exposed over a determined period of time. These assessments are based on personal monitoring data or area sampling data if available. Exposure assessments may be conducted for many types of releases including:

  • Releases in the workplace and in homes
  • Releases to ambient air and surface water
  • Releases from the management of solid wastes

  
  

• Toxicity data-

  Toxicity data is used to assess the possible health and environmental effects for exposure to substitutes. The Occupational Safety and Health Administration (OSHA) or EPA approve wide health based criteria that is available for a substitute such as:

  • Permissible Exposure Limits (PELs for occupational exposure)
  • Inhalation reference concentrations (RfCs for noncarcinogenic effects on the general population)
  • Cancer slope factors (for carcinogenic risk to members of the general population)

  If OSHA has not issued a PEL for a compound, EPA also considers Workplace Environmental Exposure Limits set by the American Industrial Hygiene Association or Threshold Limit Values set by the American Conference of Governmental Industrial Hygienists. If limits for occupational exposure or exposure to the general population are not already established, then EPA derives these values following the Agency's peer reviewed guidelines.
  
  

  Exposure information is combined with is combined with this toxicity information to explore any basis for concern. Toxicity data is used with existing EPA guidelines to develop health-based criteria for interim use in these risk characterizations.

• Flammability-

  Flammability is examined as a safety concern for workers and consumers. EPA assesses flammability risk using data on:

  • Flash point and flammability limits (e.g. OSHA flammability/ combustibility classifications)
  • Data on testing of blends with flammable components
  • Test data on flammability in consumer applications conducted by independent laboratories
  • Information on flammability risk minimization techniques

  
  

• Other environmental impacts-

  The SNAP program also examines other potential environmental impacts such as ecotoxicity and local air quality impacts. A compound that is likely to be discharged to water may be evaluated for impacts on aquatic life. Some substitutes are volatile organic compounds (VOCs), which are chemicals that increase tropospheric air pollution by contributing to ground-level ozone formation. In addition, EPA notes whenever a potential substitute is considered a hazardous air pollutant or hazardous waste.

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