The short answer
Six dates carry most of the exam's date questions: Jul 1, 1992 (venting ODS becomes unlawful), Nov 15, 1993 (certified recovery equipment — the Table 1 split), Nov 14, 1994 (technician certification + sales restriction), Nov 15, 1995 (venting ban reaches substitutes), Dec 31, 1995 (CFC production ends), and the Montreal Protocol behind all of it.
The timeline
| Date | What happened | Why the exam cares |
|---|---|---|
| Sep 16, 1987 | The Montreal Protocol is signed — the international treaty phasing out production of ozone-depleting substances (in force Jan 1, 1989). In the U.S., Clean Air Act Title VI carries it out. | It's the "which of these is an international treaty?" answer — and the framework every other date hangs on. |
| Jul 1, 1992 | Knowingly venting CFC and HCFC refrigerants during maintenance, service, repair, or disposal becomes unlawful (Clean Air Act §608(c)). | The venting prohibition's start date — the single most-asked date on the Core exam. |
| Nov 15, 1993 | Recovery and recycling equipment manufactured on or after this date must be EPA-certified (§82.158). | This date splits Table 1's two evacuation columns AND the Type I recovery rules (80% vs the 90%/80% compressor split). |
| Nov 14, 1994 | Technician certification becomes mandatory, and refrigerant sales are restricted to certified technicians, their employers, and the certified resale chain (§82.154(c) / §82.161). | One year and a day after the equipment date — the pair students most often swap (see the trap below). |
| Nov 15, 1995 | The venting prohibition extends to substitute refrigerants — HFCs and other non-exempt substitutes (§608(c)(2)). | "Venting HFCs was always illegal" is false for 1992–95; 1995 is when substitutes joined the ban. |
| Dec 31, 1995 | CFC production and import phaseout completed in developed countries under the Montreal Protocol / Title VI schedule. | Ends the CFC era: after this date, CFCs come only from recovery, recycling, and reclamation of existing stock. |
| Jan 1, 2026 | The AIM Act leak-repair rules (40 CFR §84.106) apply: HFC appliances covered at 15 lb, triggers 10/20/30. | The modern anchor date — and the one old study guides can't know about. |
The traps, named
- 1993 vs 1994: equipment certification is Nov 15, 1993; technician certification + the sales restriction are Nov 14, 1994. If a question pairs "certified" with a machine, it's 1993; with a person, 1994.
- The 35% leak trigger in old study guides is a pre-2016 key. Current triggers are 10 / 20 / 30 (comfort / commercial / industrial) — see the triggers page.
- "Montreal Protocol" is not a U.S. regulation and not the exam blueprint — it's the treaty; the Clean Air Act is the U.S. law under it.
Drill it
Dates show up across Core and the Recent Rule Changes bin.