The Observatory · Case 33 · Environment · 1974 to 2022

Montreal Protocol and U.S. ozone regulations (1974 to 2022)

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Sources checked 2026-10-19 · Preliminary research, not a final verdict
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After scientists linked CFCs to ozone loss and an Antarctic hole was reported in 1985, the U.S. Senate approved the Montreal Protocol 83 to 0 in 1988 and Congress wrote a phaseout into law in 1990; chlorine in the stratosphere is falling, but costs, smuggling, a later rise in CFC-11 and a slow recovery show the record is not simple.

In brief

In 1974 two chemists, Frank Sherwood Rowland and Mario Molina, warned that CFCs could destroy stratospheric ozone. When an Antarctic ozone hole was reported in 1985, the question moved from laboratories to legislatures. The Senate approved the Montreal Protocol 83 to 0 in March 1988, and the 1990 Clean Air Act Amendments set 2000 as the end of most U.S. CFC production. DuPont, which first said there was no imminent crisis, announced plans to leave CFCs. Households paid more to service air conditioners, and a black market in smuggled CFCs developed. Total stratospheric chlorine peaked in 1993 and had fallen 11.5 percent by 2020. The Antarctic is not expected to return to 1980 levels until about the 2060s. In 2018 scientists found that CFC-11 emissions had risen after 2012, and later data show they fell again. The case shows a public rule that worked in measurable ways, and that needed open monitoring to stay honest.

The record

Science and treaty

  • In 1974 Frank Sherwood Rowland and Mario Molina proposed that CFCs release chlorine that breaks down stratospheric ozone. A U.S. National Academy of Sciences report backed the idea in 1976. In 1985 British Antarctic Survey scientists reported very low ozone over Halley Bay, and the Vienna Convention was signed. The Montreal Protocol was signed on September 16, 1987, and entered into force January 1, 1989. (Wikipedia, Montreal Protocol; opened)
  • Amendments followed: London 1990, Copenhagen 1992, Montreal 1997 and 2007, Beijing 1999, and Kigali 2016, which phases down HFCs and entered into force January 1, 2019. (Wikipedia)
  • The Multilateral Fund, which helps developing countries comply, drew donor pledges of $3.1 billion for 1991 to 2005. (Wikipedia; amount not checked against the Fund's own report)

U.S. politics and law

  • The Senate voted 83 to 0 on March 14, 1988, to adopt Treaty Document 100-10, the Montreal Protocol. (Voteview, 100th Congress, Senate vote 467; opened) An EPA archive page dated April 5, 1988, carries a statement by Administrator Lee Thomas calling it "a monumental global environmental achievement." (EPA archive; opened)
  • Early in the debate, Interior Secretary Donald Hodel was reported to have said Americans could use sunscreen and hats rather than a treaty. TIME says President Reagan later backed a CFC treaty, and quotes George Shultz suggesting Reagan's own skin growth removal may have mattered. (TIME, April 2019; opened. The Hodel remark is "reportedly" in TIME; we did not open a primary record.)
  • DuPont founded the Alliance for Responsible CFC Policy. In 1987 DuPont told Congress there was "no imminent crisis that demands unilateral regulation." (Wikipedia; congressional testimony not opened.) By August 1988 the Christian Science Monitor reported DuPont aimed to eliminate CFC 11 and 12 by 2000, beyond the 50 percent cut the treaty required, and that EPA projected the five U.S. CFC producers could gain about $7 billion from supply shortages. (Christian Science Monitor, Aug. 12, 1988; opened)
  • The 1990 Clean Air Act Amendments, Title VI, set production limits for class I substances. Production of most class I substances, including CFCs and halons, became unlawful on January 1, 2000, and methyl chloroform on January 1, 2002. Carbon tetrachloride was cut to 15 percent from 1995. There are limited exceptions: essential methyl chloroform uses through 2005, medical devices when FDA finds them necessary, aviation halons when FAA finds no substitute, and up to 15 percent extra for developing countries. (42 U.S.C. 7671c, Cornell LII; opened)
  • EPA says the class I phaseout in the United States was implemented "4 to 6 years faster" than predicted in 1990, covered 13 more chemicals, and cost 30 percent less than predicted. (EPA, Clean Air Act 40th anniversary highlights, archived; opened)

Observations

  • The 2022 WMO and UNEP ozone assessment (summary on NOAA's site) reports total stratospheric chlorine fell 11.5 percent from a 1993 peak of 3660 parts per trillion to 3240 in 2020. Near-global ozone in 2017 to 2020 was about 2 percent below the 1964 to 1980 average. (NOAA CSL, 2022 assessment executive summary; opened, first 100,000 characters of about 122,000)
  • NASA states that measurements show "unambiguous increases in upper stratospheric ozone for 2000 to 2020 outside of the polar regions," and no statistically significant sign of recovery in Arctic ozone for 2000 to 2021. (NASA; opened)
  • In 2018 Stephen Montzka of NOAA and colleagues reported in Nature that CFC-11 emissions had risen after 2012, pointing to new production in East Asia after the 2010 phaseout. Emissions averaged about 67 gigagrams a year in 2014 to 2016, about 13 above 2002 to 2012. The Bulletin of the Atomic Scientists reports China's environment ministry began an enforcement campaign in August 2018. (Bulletin of the Atomic Scientists, 2018; opened. The Nature paper itself was not opened.) The 2022 assessment says global CFC-11 emissions fell back to 45 gigagrams in 2019 and 2020. (NOAA CSL)

Timeline

Date Event Source
1974 Rowland and Molina publish the CFC hypothesis Wikipedia
1985 Antarctic low ozone reported; Vienna Convention Wikipedia
Sept. 16, 1987 Protocol signed Wikipedia
Mar. 14, 1988 Senate votes 83 to 0 Voteview
Jan. 1, 1989 Protocol enters into force Wikipedia
1990 Clean Air Act Title VI; London Amendment Statute; Wikipedia
1993 Stratospheric chlorine peak NOAA CSL
Jan. 1, 2000 U.S. production of most class I substances unlawful 42 U.S.C. 7671c
2007 EPA says Antarctic ozone could return to 1980 levels 2060 to 2075 EPA release
2016, 2019 Kigali Amendment adopted, in force Wikipedia
2018 Unexpected CFC-11 emissions reported Bulletin

Costs and smuggling

  • A 1995 Christian Science Monitor report said about 10,000 tons of CFCs were expected to be smuggled into the United States that year, mostly through Miami. The federal excise tax was $5.35 a pound, and prices rose to about $15 a pound from $1 in 1989. It put lost taxes and duties above $100 million a year. Agents cited were from Operation Cool Breeze. (Christian Science Monitor, Oct. 23, 1995; opened. The figures are the newspaper's, not a court or agency record.)
  • A June 1994 paper by Ben Lieberman of the Competitive Enterprise Institute, which criticized the accelerated phaseout, estimated costs of $44.5 to $99.4 billion over a decade for refrigeration and air conditioning, about $445 to $994 per household. It uses surveys and stated assumptions, and it excludes some costs as speculative. (Lieberman, The High Cost of Cool; opened)
  • EPA estimated in 1999 that the ozone actions would yield $4.2 trillion in U.S. health benefits from 1990 to 2165 and prevent 6.3 million skin cancer deaths. (EPA release, April 26, 2007; opened) Another EPA page gives 295 million avoided non-melanoma skin cancer cases for 1990 to 2165. Both are projections far into the future.

Disputed or differing numbers

| Item | Figure A | Figure B | Notes | |---|---|---| | U.S. cost of the phaseout | $44.5 to $99.4 billion over a decade, refrigeration and air conditioning (Lieberman, 1994) | EPA: 30 percent below 1990 predictions (EPA 40th anniversary page) | Different scope; EPA gives no dollar total on the page opened | | Antarctic return to 1980 levels | about 2065 or 2066 (NOAA CSL 2022) | 2060 to 2075 (EPA 2007) | Newer assessment narrower | | Benefits | 295 million cases avoided (EPA page) | 6.3 million deaths avoided (EPA 2007 release) | Cases versus deaths; both to 2165 | | Smuggled CFCs, 1995 | about 10,000 tons expected (CSM) | not verified | Press estimate | | Date of U.S. action | Senate vote March 14, 1988 | EPA statement April 5, 1988 | Consent versus final act; not reconciled |

What this case shows

  1. A global problem decided in a public record. Scientists published, the Senate voted 83 to 0, and Congress wrote dates into a statute. Ordinary people could read a year, 2000, and hold officials to it. (Voteview; 42 U.S.C. 7671c)
  2. Public pressure and industry both mattered. DuPont first said there was no imminent crisis, then moved to a full phaseout once substitutes were in view. The record shows an industry interest and a public interest aligning, and also that producers expected to gain from shortages. (Wikipedia; CSM 1988)
  3. Costs fell on identifiable people. Households paid more for car air conditioner service and refrigerants. Critics put numbers on it. Supporters cite EPA's finding that costs came in 30 percent below prediction. Voters could see both claims. (Lieberman; EPA)
  4. Enforcement failures were visible. A black market in CFCs grew while the excise tax and ban pushed prices up, and in 2018 new emissions were found by monitoring stations. Open atmospheric data let outsiders catch a violation that official reports did not show. (CSM 1995; Bulletin)
  5. Recovery is slow, so a vote taken in 1988 is judged in 2060. The people who pay now are not the only people who benefit. (NOAA CSL)

The strongest objections, and our answers

  1. Objection: The science was uncertain and the phaseout was too fast and too costly. Mitigation: We cite Lieberman's estimate and note it was a 1994 projection that EPA later said overstated costs. We also report that a House subcommittee hearing in 1995 asked whether CFC damage was overstated, from the CSM article; we did not open the hearing record.
  2. Objection: It was a clear success and critics were wrong. Mitigation: Chlorine is falling and upper stratosphere ozone is rising. But the Arctic shows no recovery signal, the Antarctic is not expected back until the 2060s, and CFC-11 emissions rose after 2012. Success is partial and still being measured.
  3. Objection: Credit belongs to industry substitutes, not government. Mitigation: Both are in the record. DuPont moved after the treaty and the science; the statute set the 2000 date. We do not rank them.
  4. Objection: Projections like $4.2 trillion are not facts. Mitigation: Agreed. We label them EPA projections to 2165 and keep them apart from observed data. We cite the observed chlorine decline separately.
  5. Objection: The smuggling story is a press anecdote. Mitigation: It rests on one newspaper report. DOJ press releases on CFC smuggling appeared in search results but were not opened. We mark the 10,000 ton figure as an expectation reported by the press.

Open questions: what would change our minds

  • The 1987 DuPont congressional testimony and the exact date of DuPont's phaseout announcement were not opened. The CSM article does not mention a March 1988 announcement.
  • The Hodel sunscreen remark is reported by TIME as reported speech. No primary record was opened.
  • The Wikipedia figure of $3.1 billion for the Multilateral Fund was not checked against the Fund's records.
  • The EPA 1999 benefits report (source of $4.2 trillion and 6.3 million deaths) was not opened; only EPA's later summaries were.
  • Whether Lieberman's cost figures were borne out: no independent study was opened.
  • Details of Title VI beyond section 7671c (service rules, labeling, the excise tax) and of the HCFC phaseout and the 2020 AIM Act for HFCs were not opened. EPA's regulatory page refused our fetch.
  • The U.S. Senate hearing record and ratification instrument date are not reconciled with the EPA April 1988 statement.
  • The CFC-11 Nature paper and the identity of producers were not opened; the Bulletin article is a secondary account.
  • The last 22,000 characters of the NOAA 2022 executive summary were not read.
  • If measured Antarctic ozone failed to recover by the 2030s, or CFC-11 emissions rose again, the claim of success would weaken.

Sources

Title Publisher URL Supports Opened?
Montreal Protocol Wikipedia https://en.wikipedia.org/wiki/Montreal_Protocol Timeline, amendments, DuPont, Fund Yes
Senate vote 467, 100th Congress Voteview https://voteview.com/rollcall/RS1000467 83 to 0, March 14, 1988 Yes
Lee M. Thomas statement EPA archive https://www.epa.gov/archive/epa/aboutepa/lee-m-thomas-statement-us-ratification-montreal-protocol.html Quote, date Yes
How Reagan helped save the ozone layer TIME https://time.com/5564651/reagan-ozone-hole/ Hodel, Reagan, Shultz Yes
Industry scrambles to find ozone-safe CFC substitutes Christian Science Monitor https://www.csmonitor.com/1988/0812/fpont.html DuPont, EPA $7 billion estimate Yes
42 U.S.C. 7671c Cornell LII https://www.law.cornell.edu/uscode/text/42/7671c Phaseout dates, exceptions Yes
Clean Air Act 40th anniversary highlights EPA (archived) https://19january2025snapshot.epa.gov/clean-air-act-overview/highlights-clean-air-act-40th-anniversary 30 percent cheaper, 295 million cases Yes
EPA release, April 26, 2007 EPA archive https://www.epa.gov/archive/epapages/newsroom_archive/newsreleases/12abfb1623bc8cc0852572c9005cc8f2.html $4.2 trillion, recovery 2060 to 2075 Yes
Scientific Assessment of Ozone Depletion 2022, executive summary NOAA CSL https://csl.noaa.gov/assessments/ozone/2022/executivesummary/ Chlorine, recovery, Kigali, CFC-11 Yes, partly
Earth's ozone layer on track to recover NASA https://science.nasa.gov/mission/aura/earths-ozone-layer-on-track-to-recover-within-decades Upper stratosphere increase, Arctic Yes
Unexpected, unreported CFC-11 emissions Bulletin of the Atomic Scientists https://thebulletin.org/2018/09/unexpected-unreported-and-so-far-unexplained-emissions-of-cfc-11/ Montzka finding Yes
Miami Ice: Freon smuggling Christian Science Monitor https://www.csmonitor.com/1995/1023/23031.html Smuggling, tax Yes
The High Cost of Cool (1994) Competitive Enterprise Institute https://cei.org/wp-content/uploads/2010/10/Ben-Lieberman-The-High-Cost-of-Cool-The-Economic-Impact-of-the-CFC-Phaseout-in-the-United-States.pdf Critics' cost estimate Yes
EPA regulatory programs for stratospheric ozone EPA https://www.epa.gov/ozone-layer-protection/regulatory-and-voluntary-programs-protect-stratospheric-ozone Not read No, blocked
PMC article on avoided skin cancer (PMC8422883) PubMed Central https://pmc.ncbi.nlm.nih.gov/articles/PMC8422883 Not read No, blocked by browser check

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