Montreal Protocol

(updated to take into account Decision XXXV/5 of the 35th Meeting of the Parties to the Montreal Protocol)

The Montreal Protocol on Substances that Deplete the Ozone Layer was signed on September 16, 1987, in Montreal, Canada. As of January 2021, 196 countries and the European Union were parties to the Montreal Protocol.

Initially, the treaty provided for freezing and phasing out of five most commonly used chlorofluorocarbons (CFCs) and halons and limiting export and import of ozone-depleting substances (ODSs).

Later amendments extended the protocol to other CFCs, hydrochlorofluorocarbons (HCFCs), ODSs, and even substances that do not deplete the ozone layer but feature considerable global warming potential, hydrofluorocarbons (HFCs).

Article 5.1 of the Montreal Protocol stipulates that the Parties to the Protocol approve the destruction technology. The first version of the list was introduced with the report on the Fourth Meeting of the Parties (November 23–25, 1992, Copenhagen, Denmark). The list was subsequently adjusted and supplemented by decisions of the Meetings of the Parties to the Montreal Protocol.

Annex II to the Decision XXX/6 of the 30th Meeting of the Parties (November 5–9, 2018, Quito, Ecuador) presents destruction technologies and status of their approval in the table form.

Decision XXXV/5 of the 35th Meeting of the Parties amends the list as follows:

cement kiln was approved as destruction technology for diluted sources of ozone-depleting substances and Annex F, group I substances for which there is already approval for concentrated sources;
portable plasma arc technology was removed as a separate approved technology, given that this technology is a subset of the already-approved category of nitrogen plasma arc destruction technology.

With all additions and corrections, the list took the following form (view in PDF format).

Technology	Applicability
	Concentrated Sources									Dilute Sources
	Annex A		Annex B			Annex C	Annex E	Annex F			Annex F
	Group 1	Group 2	Group 1	Group 2	Group 3	Group 1	Group 1	Group 1	Group 2		Group 1
	Primary CFCs	Halons	Other CFCs	Carbon Tetrachloride	Methyl Chloroform	HCFCs	Methyl Bromide	HFCs	HFC-23	ODSs	HFCs
DRE*	99.99%	99.99%	99.99%	99.99%	99.99%	99.99%	99.99%	99.99%	99.99%	95%	95%
Cement Kilns	Approved	Not approved	Approved	Approved	Approved	Approved	Not determined	Approved	Not determined	Approved	Approved
Gaseous/Fume Oxidation	Approved	Not determined	Approved	Approved	Approved	Approved	Not determined	Approved	Approved
Liquid Injection Incineration	Approved	Approved	Approved	Approved	Approved	Approved	Not determined	Approved	Approved
Municipal Solid Waste Incineration										Approved	Approved
Porous Thermal Reactor	Approved	Not determined	Approved	Approved	Approved	Approved	Not determined	Approved	Not determined
Reactor Crackin	Approved	Not approved	Approved	Approved	Approved	Approved	Not approved	Approved	Approved
Rotary Kiln Incineration	Approved	Approved	Approved	Approved	Approved	Approved	Not determined	Approved	Approved	Approved	Approved
Rotary Kiln Incineration	Approved	Approved	Approved	Approved	Approved	Approved	Not determined	Approved	Approved
Inductively Coupled Radio Frequency Plasma	Approved	Approved	Approved	Approved	Approved	Approved	Not determined	Not determined	Not determined
Microwave Plasma	Approved	Not determined	Approved	Approved	Approved	Approved	Not determined	Not determined	Not determined
Nitrogen Plasma Arc	Approved	Not determined	Approved	Approved	Approved	Approved	Not determined	Approved	Approved
Chemical Reaction with H₂ and CO₂	Approved	Approved	Approved	Approved	Approved	Approved	Not determined	Approved	Approved
Gas Phase Catalytic Dehalogenation	Approved	Not determined	Approved	Approved	Approved	Approved	Not determined	Approved	Not determined
Superheated Steam Reactor	Approved	Not determined	Approved	Approved	Approved	Approved	Not determined	Approved	Approved
Thermal Reaction with Methane	Approved	Approved	Approved	Approved	Approved	Approved	Not determined	Not determined	Not determined
Thermal Decay of Methyl Bromide	Not determined	Not determined	Not determined	Not determined	Not determined	Not determined	Approved	Not determined	Not determined

* — Destruction & Removal Efficiency