Refrigerant Safety for the EPA 608 Exam
Updated October 27, 2026
Safety questions are part of the EPA 608 Core section and come up in the type sections too. Most of them come down to a few hazards: suffocation, frostbite, overpressure and toxic gases from heat. Here’s what to know, followed by free practice questions.
The main hazards
- Suffocation: refrigerant vapor is heavier than air and can displace oxygen in an enclosed space, causing suffocation without warning. Ventilate, and use proper breathing protection for a large leak in a confined area.
- Frostbite: liquid refrigerant evaporates very fast and can freeze skin and eyes. Wear safety glasses and gloves.
- Toxic gases from heat: refrigerants exposed to an open flame or very hot surfaces can break down into toxic and corrosive substances, such as phosgene and hydrofluoric acid.
- Overpressure: heat raises pressure in a closed cylinder or system. Never heat a cylinder with an open flame, and never fill a recovery cylinder beyond 80%.
Pressurizing a system safely
- Use dry nitrogen with a pressure regulator and a relief valve.
- Never pressurize with oxygen or compressed air: mixed with oil under pressure, they can explode.
- Don’t exceed the system’s design pressure, or the low-side test pressure on the nameplate.
Safety groups
ASHRAE 34 classifies refrigerants by toxicity and flammability. The letter is toxicity (A = lower, B = higher). The number is flammability (1 = no flame propagation, 2L = lower flammability, 2 = flammable, 3 = higher flammability). Most common HVAC refrigerants, such as R-22 and R-410A, are A1.
Free refrigerant safety practice questions
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Why is a refrigerant leak in an enclosed space dangerous?Answer: BRefrigerant vapor is heavier than air and can push out oxygen in low or enclosed spaces, causing suffocation.
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A technician needs to pressurize a system to find a leak. Which gas is the right choice?Answer: CUse dry nitrogen with a regulator and relief valve. Oxygen and compressed air can explode when mixed with oil under pressure.
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What can happen when refrigerant is exposed to an open flame?Answer: DRefrigerants exposed to flame or very hot surfaces can decompose into toxic and corrosive substances, including phosgene and hydrofluoric acid.
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In the ASHRAE safety group "A1," what does the "A" mean?Answer: AThe letter is toxicity: A means lower toxicity and B means higher toxicity. The number shows flammability.
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What protective equipment protects against frostbite from liquid refrigerant?Answer: BLiquid refrigerant can freeze skin and eyes on contact, so wear safety glasses and gloves when handling it.
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Is it safe to heat a refrigerant cylinder with a torch to speed up charging?Answer: CHeating a cylinder with an open flame can raise the pressure dangerously and decompose the refrigerant. Never use a torch on a cylinder.
Pass the EPA 608 exam on your first try
- All 168 questions across Core, Type I, Type II and Type III
- An explanation for every answer, with the rule or principle behind it
- Unlimited practice exams per section, scored like the real test (18 of 25 to pass)