EPA 608 Practice Test

EPA 608 Core Practice Questions

Core makes up 18 of every 50 questions on a Tigertest EPA 608 practice test. Here are 10 of the 72 questions on it, each with the answer and the reason.

Updated 2026-11-10 by the Tigertest team. Based on 40 CFR Part 82 Subpart F and the EPA Section 608 test outline. Each real section is 25 questions, 18 to pass.

1. 1. In which layer of the atmosphere is the ozone layer that shields the Earth from harmful ultraviolet radiation?

   • A.Lower troposphere
   • B.Stratosphere
   • C.Mesosphere
   • D.Thermosphere

   Answer: B. The protective ozone layer lies in the stratosphere, roughly 6 to 30 miles above the Earth. Ozone near the ground in the troposphere is a smog pollutant, not a UV shield.

2. 2. Which type of solar radiation does the stratospheric ozone layer absorb, protecting people, crops, and marine life?

   • A.Visible light from the sun
   • B.Cosmic gamma radiation
   • C.Infrared heat radiation from the sun
   • D.Ultraviolet-B (UV-B) radiation

   Answer: D. Stratospheric ozone absorbs most incoming UV-B radiation. Thinner ozone lets more UV-B reach the surface, increasing skin cancer, cataracts, and crop and marine damage.

3. 3. When a free chlorine atom released from a CFC molecule strikes an ozone molecule, what is formed?

   • A.Chlorine monoxide and an oxygen molecule
   • B.Hydrochloric acid and carbon dioxide
   • C.Fluorine gas and water vapor
   • D.Chlorine dioxide and a new ozone molecule

   Answer: A. Cl + O3 forms ClO + O2; the ClO then reacts with a free oxygen atom and releases the chlorine atom again. Because chlorine is regenerated, one atom can destroy roughly 100,000 ozone molecules.

4. 4. Halons used in fire suppression contain bromine. How does bromine compare with chlorine in destroying stratospheric ozone?

   • A.It only harms ozone in the troposphere
   • B.It is less destructive than chlorine
   • C.It is far more destructive per atom
   • D.It does not react with ozone at all

   Answer: C. Bromine destroys ozone through the same catalytic cycle as chlorine but is many times more effective per atom. That is why halons have much higher ozone depletion potentials than CFCs.

5. 5. Which refrigerant has an ozone depletion potential of zero but a relatively high global warming potential?

   • A.R-11
   • B.R-12
   • C.R-410A
   • D.R-22

   Answer: C. R-410A is an HFC blend with no chlorine, so its ODP is zero, but its GWP is about 2,088 compared with CO2 at 1. R-11, R-12, and R-22 contain chlorine and deplete ozone.

6. 6. A customer asks which refrigerant in their facility contributes to ozone depletion. Which one should the technician identify?

   • A.HCFC-22 (R-22)
   • B.HFC-32 (R-32)
   • C.HFO-1234yf (R-1234yf)
   • D.HFC-134a (R-134a)

   Answer: A. HCFCs such as R-22 contain chlorine and have an ODP of about 0.055. HFCs and HFOs contain no chlorine and have an ODP of zero, although HFCs can have high GWPs.

7. 7. Scientists describe the Antarctic ozone hole as areas where total column ozone falls below about how many Dobson units?

   • A.300 Dobson units
   • B.1,000 Dobson units
   • C.100 Dobson units
   • D.220 Dobson units

   Answer: D. Total column ozone is measured in Dobson units; the global average is about 300 DU. The ozone hole is defined as the region where ozone falls below 220 DU.

8. 8. Since what date has the Clean Air Act prohibited knowingly venting CFC and HCFC refrigerants during service, maintenance, or disposal?

   • A.November 14, 1994
   • B.July 1, 1992
   • C.November 15, 1995
   • D.January 1, 2010

   Answer: B. Section 608 of the Clean Air Act made it illegal to knowingly vent ozone-depleting refrigerants as of July 1, 1992 (40 CFR 82.154(a)). Only de minimis releases during good-faith recovery are allowed.

9. 9. A technician servicing an R-410A heat pump claims HFCs may be vented because they do not deplete ozone. Since when has venting HFCs been illegal?

   • A.January 1, 2025
   • B.November 15, 1995
   • C.July 1, 1992
   • D.September 30, 2020

   Answer: B. Section 608(c)(2) extended the venting prohibition to substitute refrigerants such as HFCs on November 15, 1995. Only specifically exempted substitutes, such as CO2 in certain uses, may be released.

10. 10. Under the Montreal Protocol and the Clean Air Act, U.S. production of CFC refrigerants such as R-12 ended at the end of which year?

    • A.2020
    • B.1987
    • C.2010
    • D.1995

    Answer: D. The 1987 Montreal Protocol set the phase-out schedule, and U.S. production of CFCs for refrigeration ended on December 31, 1995. Since then CFC equipment relies on existing, recovered, or reclaimed stocks.