The Montreal Protocol is an international treaty that phases out the production and consumption of ozone-depleting substances (ODS) and, under the 2016 Kigali Amendment, high-global-warming-potential hydrofluorocarbons (HFCs). Adopted on 16 September 1987 and entered into force on 1 January 1989, the protocol is administered by the UN Environment Programme through the Ozone Secretariat in Nairobi. Universal ratification has been achieved, every UN member state is a party. The protocol covers 96 listed substances across five annexes and is widely considered the most successful environmental treaty in history, having delivered measurable recovery of the stratospheric ozone layer.
What the protocol controls
| Annex | Substances | Phase-out class |
|---|---|---|
| Annex A Group I | Five CFCs (CFC-11, -12, -113, -114, -115) | Phased out by 2010 globally |
| Annex A Group II | Three halons (Halon 1211, 1301, 2402) | Phased out by 2010 globally |
| Annex B Group I | Ten other CFCs | Phased out by 2010 globally |
| Annex B Group II | Carbon tetrachloride | Phased out by 2010 globally |
| Annex B Group III | Methyl chloroform | Phased out by 2015 globally |
| Annex C Group I | HCFCs (39 substances including HCFC-22, HCFC-141b, HCFC-142b) | Phasing out 2013-2040 by Article 5 status |
| Annex E | Methyl bromide | Phased out 2005-2015 with critical-use exemptions |
| Annex F (Kigali Amendment) | 18 HFCs (HFC-134a, HFC-23, HFC-125, HFC-32, others) | Phasing out 2019-2047 by Article 5 status |
Article 5 status determines the phase-out schedule. Developed countries (non-Article-5) phase out earlier and faster. Developing countries (Article 5) phase out later with longer transition windows. China is an Article 5 party, so its HCFC and HFC phase-out schedule is later than the US, EU, or Australia schedule.
China’s Article 5 schedule
China is the world’s largest producer and consumer of HCFCs and HFCs. The China-specific phase-out targets:
| Substance | China target |
|---|---|
| HCFC-22 (refrigerant; chemical intermediate for fluoropolymer production) | 67.5% reduction from baseline by 2025; 97.5% by 2030; complete by 2040 |
| HCFC-141b (foam-blowing agent) | Phase out completed by 2026 in foam manufacturing applications |
| HCFC-142b (foam, refrigerant) | Following the broader HCFC schedule |
| HFC-134a (mobile air-conditioning, foam) | 10% reduction by 2029; 30% by 2035; 80% by 2045 |
| HFC-23 (by-product of HCFC-22 production) | Captured and destroyed under the Multilateral Fund mechanism |
The phase-out is enforced through the Chinese Ministry of Ecology and Environment (MEE), which administers production and consumption quotas annually. Producers and importers must hold a quota allocation to legally produce or import controlled substances within the year.
What a Chinese exporter must do for ODS or HFC cargo
For a chemical shipment from China that contains an Annex A, B, C, E, or F substance, the exporter must:
- Confirm the substance is on a current production/import quota. If the producer’s quota for the year is exhausted, no further export is legally possible until the next year’s allocation.
- Obtain the Montreal Protocol export licence. Issued by MEE through the Ozone Secretariat office. The licence references the specific substance, quantity, and destination country.
- Confirm the importing country’s import licence. The Montreal Protocol requires both export and import licences for controlled substances. Both must be in place before customs clearance on either side.
- Match the HS code. ODS and HFC chemicals have specific HS codes that customs authorities use to flag controlled substances. The commercial invoice and customs declaration must use the correct codes.
- Maintain records. Export volumes are reported annually to the Ozone Secretariat through national reporting obligations.
A Chinese factory shipping HFC-134a to the US must hold a Chinese export quota and licence; the US importer must hold a 2024 EPA HFC import allocation under the AIM Act (the US implementation of the Kigali Amendment). Without both, the cargo is held at one customs or the other.
How the protocol catches exporters off guard
Three failure patterns recur:
- Quota exhaustion mid-year. A factory producing HCFC-22 hits its annual production quota in October and cannot legally produce more for export until January. A signed contract for November shipment goes into dispute or force majeure.
- Importing country quota changes. The US AIM Act allocations are revised annually. An importer’s allocation can drop year-on-year, forcing them to find alternative refrigerants or accept reduced volumes.
- HS code misclassification. A product containing 5% HCFC-22 by weight may be shipped under a non-controlled HS code, causing it to clear customs without the export licence. When the misclassification is discovered, retroactive penalties and licence-restoration delays follow.
The mitigation: Chinese factories producing controlled substances should maintain a quota dashboard that tracks production-to-date against the annual allocation, and book export shipments only against confirmed remaining allocation.
How Montreal interacts with other treaties
The protocol is one of several treaties governing chemical trade:
| Treaty | Scope |
|---|---|
| Montreal Protocol | Ozone-depleting substances + Kigali HFCs |
| Stockholm Convention | Persistent Organic Pollutants |
| Rotterdam Convention | PIC for hazardous chemicals and pesticides |
| Basel Convention | Hazardous waste trade |
| Minamata Convention | Mercury and mercury compounds |
Some chemicals appear under multiple treaties. Methyl bromide is Annex E under Montreal (phased out from agriculture under critical-use exemptions) and is not on Stockholm. Carbon tetrachloride is Annex B under Montreal (phased out) and is also tightly controlled under most national chemical regimes for non-feedstock use.
The Multilateral Fund
Article 5 parties (developing countries including China) receive technical and financial assistance from the Multilateral Fund for the Implementation of the Montreal Protocol. The Fund finances:
- HCFC-22 by-product (HFC-23) destruction at production facilities
- Phase-out of HCFCs in foam manufacturing
- Conversion of refrigeration servicing to non-ODS alternatives
- Capacity building for licensing systems
China has been the largest single recipient. The funding has been instrumental in delivering the production-side phase-out, a Chinese HCFC-22 factory that converts to alternative refrigerant production receives Fund support that would otherwise sit on the factory’s capital expenditure budget.
Related terms
Stockholm Convention is the parallel treaty for Persistent Organic Pollutants. Rotterdam Convention is the trade-side PIC framework. REACH and TSCA are the EU and US chemical regimes that incorporate Montreal phase-outs into domestic law. MEE China is the Chinese authority for the Montreal Protocol implementation. HS Code classification is critical for customs control of ODS and HFC cargoes.