EPA 608 Core study guide: Clean Air Act, refrigerant law, and venting rules

Core is the shared foundation: the Core section must be passed before any Type credential or Universal certification is issued, and it tests federal law rather than service procedure.

What the EPA 608 Core section tests

The Core section tests every topic on the official EPA outline: ozone depletion, the Clean Air Act and Montreal Protocol, Section 608 regulations, refrigerant classification, the three R's, safety, and shipping. Here is each exam topic and where this guide covers it:

Core exam topic	What the questions ask	Covered in
Ozone depletion	How chlorine destroys ozone, UV health effects, evidence it is manmade	Ozone and the Montreal Protocol
Clean Air Act & Montreal Protocol	1987 treaty, 1990 CAA amendment, phaseout and effective dates	Ozone and the Montreal Protocol
Section 608 regulations	Venting prohibition, effective dates, civil penalties, who can report	Venting and penalties
Refrigerant classification	CFC vs HCFC vs HFC vs HFO, ODP and GWP ranking	Refrigerant categories
Recovery, recycling, reclamation	Three legal definitions, who performs each, ARI-700	The three R's
Sales restriction	Who may legally buy regulated refrigerant	Sales restriction
Safety and shipping	PPE, cylinder rules, leak detection, DOT labeling	Safety, cylinders, and shipping

The statute applies to any technician who opens a refrigerant circuit to service, maintain, repair, or dispose of equipment. For a one-page review of every date and figure below, use the EPA 608 cheat sheet.

Venting prohibitions and civil penalties

Venting refrigerants into the atmosphere is prohibited under Section 608 of the Clean Air Act. For CFCs and HCFCs, the prohibition took effect July 1, 1992. For HFCs, it took effect November 15, 1995.

The prohibition has two effective dates that the Core exam specifically tests:

July 1, 1992. Venting of CFCs (chlorofluorocarbons) and HCFCs (hydrochlorofluorocarbons) became prohibited during service, maintenance, repair, and disposal of refrigeration and air conditioning equipment. R-12, R-22, R-11, and R-113 are covered from this date.

November 15, 1995. HFCs (hydrofluorocarbons) were added to the venting prohibition. R-134a, R-410A, R-404A, R-507, and all HFC blends become covered from this date. The 1995 date is the one most often missed by technicians who memorize only one date.

The de minimis exemption: recovery is not required for refrigerant releases of 0.1 ounce or less. This threshold is the de minimis exemption, the only quantity based exception to the recovery obligation; the releases below are exempt for other reasons. Releases above this amount require recovery equipment.

Releases that do not violate Section 608. The exam tests four lawful releases alongside the prohibition itself:

• De minimis releases while making a good faith attempt to recover, recycle, or dispose of refrigerant
• Releases during normal equipment operation, such as a purge unit venting on a low pressure chiller, as opposed to releases during service
• Small releases when purging gauge manifold hoses; recovery and recycling equipment manufactured after November 15, 1993 must have low-loss fittings to minimize this
• Release of a CFC or HCFC that is not being used as a refrigerant, such as an R-22 and nitrogen mix used as a holding charge (you may not add nitrogen to refrigerant to claim this exemption)

Who can report violations: any person, including fellow technicians, building owners, or environmental advocacy groups, may report Section 608 violations. The EPA does not require the reporter to be an inspector or agency employee. This is the citizen suit provision and is frequently tested.

Refrigerant categories: CFCs, HCFCs, HFCs, HFOs

The Core section tests refrigerant classification by ozone depletion potential (ODP) and global warming potential (GWP). Four categories appear:

CFCs (chlorofluorocarbons): highest ODP, fully phased out from production in the United States. Examples: R-11, R-12, R-113. The 1987 Montreal Protocol mandated the CFC phaseout. CFCs may still exist in older equipment.

HCFCs (hydrochlorofluorocarbons): lower ODP than CFCs but not zero. R-22 is the most commonly tested HCFC. R-22 new equipment production ended January 1, 2010, and all R-22 production ended January 1, 2020. Reclaimed R-22 is still legal for servicing existing equipment.

HFCs (hydrofluorocarbons): zero ODP but high GWP. Covered by the Section 608 venting prohibition since 1995. R-410A, R-134a, and R-404A are common HFCs. The AIM Act mandates an HFC phasedown, with the R-410A new equipment ban effective January 1, 2025. See our AIM Act 2026 refrigerant changes guide for phasedown deadlines and A2L transition details.

HFOs (hydrofluoroolefins): zero or near zero ODP and very low GWP. R-1234yf (automotive) and R-1234ze are examples. HFOs and HFO blends (A2L refrigerants like R-454B and R-32) are the next generation replacements; the low-GWP refrigerants guide covers how the exam tests them.

ESCO Institute, Mainstream Engineering, and HVAC Excellence all test Core section refrigerant classification. The question format varies by provider, but the underlying facts are the same.

Ozone depletion and the Montreal Protocol

The Core exam tests the mechanism, not just the vocabulary: chlorine released from CFC and HCFC refrigerants destroys stratospheric ozone, and a single chlorine atom destroys thousands of ozone molecules before it degrades. That chain reaction is why venting is a federal offense.

• Where ozone matters: ozone in the stratosphere filters UV radiation and is protective. Ozone in the troposphere, near ground level, is smog and a pollutant. The exam asks you to distinguish the two.
• UV health effects: increased skin cancer, eye cataracts, and weakened immune systems are the tested consequences of ozone depletion.
• Evidence it is manmade: chlorine monoxide in the stratosphere is short lived, so its presence proves an ongoing chlorine source. Natural chlorine dissolves in rain and never reaches the stratosphere; CFC molecules do not, and release chlorine only when UV breaks them apart at altitude.

The regulatory response is a timeline the Core exam tests date by date:

Date	Event
1987	Montreal Protocol signed: international treaty phasing out ozone depleting substances, including CFCs, HCFCs, and halons
1990	Clean Air Act amended: Title VI gives the EPA authority over stratospheric ozone protection
July 1, 1992	Venting prohibition takes effect for CFCs and HCFCs
November 15, 1993	Recovery and recycling equipment manufactured after this date must be third party certified by an EPA approved organization and use low-loss fittings
November 15, 1995	Venting prohibition extended to HFC substitutes
January 1, 1996	CFC production and import banned in the United States; existing and reclaimed stock may still be used
2010 / 2020	R-22 banned in new equipment, then all R-22 production ends

Recovery, recycling, and reclamation

Recovery means removing refrigerant from a system into an external container without testing or processing it. Recycling means cleaning refrigerant for reuse on site. Reclamation means processing refrigerant to ARI-700 purity standards, and only EPA certified reclaimers may reclaim.

Recovery: removing refrigerant from a system and storing it in an external container, without necessarily testing or processing the refrigerant. Any certified technician performs recovery on site using approved recovery equipment. The recovered refrigerant does not need to meet any purity standard at the time of recovery.

Recycling: cleaning recovered refrigerant using oil separation and single or multiple passes through filter driers. Recycling occurs on site or at a facility. Recycled refrigerant meets a reduced contaminant standard but NOT the ARI-700 purity standard required for sale as new refrigerant. Recycled refrigerant may only be returned to the original owner's equipment.

Reclamation: reprocessing recovered refrigerant to ARI-700 purity standards, the same standard as virgin refrigerant. Reclamation must be performed at an EPA certified reclamation facility. Only reclaimed refrigerant may be sold to a different owner. A certified reclaimer issues the purity documentation.

The Core exam frequently asks which process is required before selling refrigerant (reclamation), which process can be performed on site (recycling), and which process must be performed by a third party EPA certified facility (reclamation).

Safety, cylinders, and shipping

The Core exam tests three cylinder facts more than any others: recovery cylinders are gray with a yellow top, disposable cylinders must never be refilled, and no cylinder is ever filled past 80% of capacity. The rest of the safety material follows the same pattern of short, absolute rules.

Cylinder rules:

• Refillable recovery cylinders are DOT approved, gray with a yellow top, and are the only cylinders used for recovered refrigerant
• Disposable cylinders (DOT Specification 39) are single use. Refilling one is a violation; empty them to zero pressure and render them unusable
• Never fill any cylinder beyond 80% liquid capacity, to leave room for expansion
• Never apply open flame or direct heat to a refrigerant cylinder
• Never mix refrigerants in a recovery cylinder; a mixed cylinder usually cannot be reclaimed

Exposure and PPE: wear safety glasses and gloves whenever refrigerant can escape; liquid refrigerant at atmospheric pressure causes frostbite. Refrigerant vapor is heavier than air and displaces oxygen in confined spaces, so ventilate first and use a self contained breathing apparatus (SCBA) where a large release is possible. Open flames and hot surfaces decompose refrigerant into hydrochloric acid, hydrofluoric acid, and phosgene gas, so recover refrigerant before soldering or welding on a circuit.

Leak detection: pressure test with dry nitrogen, never with compressed air or oxygen; compressed oxygen in contact with refrigerant oil is explosive. Always use a pressure regulator and a relief valve on a nitrogen cylinder, and never install relief valves in series. If a pressure test cannot locate the leak, the EPA allows a trace gas as a last resort: nitrogen with a small amount of the system's refrigerant, found with an electronic detector.

Shipping: refrigerant cylinders ship as DOT hazardous materials. They must carry a DOT classification tag identifying the refrigerant, travel secured upright, and refillable cylinders must be hydrostatically retested every five years. The Type I study guide covers the recovery equipment requirements that build on these rules.

Who can buy refrigerant: the sales restriction

Only EPA 608 certified technicians may purchase regulated refrigerants, under the sales restriction in 40 CFR Part 82. Wholesalers must verify certification before selling and retain sales records, which is why distributors ask for your card number at the counter. The exam tests this as a one line fact: sale of CFC, HCFC, and HFC refrigerants is restricted to certified technicians, and an employer's certification can cover technicians buying on its behalf. This is the rule that makes the certification itself legally meaningful, and it is why Core plus at least one Type section is the minimum credential for field work.

The refrigerant lifecycle

Stage	Action	Who performs	Regulatory requirement
Production	Manufacture of virgin refrigerant	Refrigerant manufacturer	EPA and AIM Act production limits apply
Distribution	Sale and transfer of virgin or reclaimed refrigerant	Distributors, wholesalers	Must be sold to certified technicians or purchase verified buyers
Recovery	Removal from equipment into recovery cylinder	Any EPA 608 certified technician	Required before opening refrigerant circuit; recovery equipment must be EPA certified
Recycling	Cleaning recovered refrigerant on site	Certified technician at service site	May only return to original owner's equipment; does NOT meet ARI-700 purity standard
Reclamation	Reprocessing to ARI-700 standard	EPA certified reclamation facility only	Required before selling refrigerant to a new owner; reclaimer documents purity
Reclamation sale	Sale of reclaimed refrigerant	Certified reclaimers, distributors	Reclaimed refrigerant is the legal equivalent to virgin refrigerant for all service purposes

This sequence is the Core section's underlying logic: refrigerant moves from production through use, must be recovered before equipment is opened, and must be reclaimed before it can be resold, and is never vented at any stage. For more study resources, see our EPA 608 practice test with answers, where each answer includes the regulatory citation so you can trace every question back to the source.

Core section FAQ

Practice questions