International Programs
Stratospheric Ozone Layer Depletion
Key Topics
- Air Quality and Public Health
- Transboundary Air Pollution
- Air Quality Management Manual
- Air Quality: Methods, Tools, and Training
- Global Climate Change
- Stratospheric Ozone
- Toxic Air Pollutants
- Indoor Air Quality
- Transportation and Air Quality
- Initiatives and Partnerships
- Bilateral and International Agreements
- Partners
Note: EPA no longer updates this information, but it may be useful as a reference or resource.
EPA's Stratospheric Ozone website provides information about the science of ozone depletion, information about the regulatory approach to protecting the ozone layer, and information on alternatives to ozone-depleting substances, as well as information on a number of other topics.
EPA has an Ozone Depletion Resource Center, which provides quick access to a variety of useful information.
The Montreal Protocol is the international treaty which was developed after the scientific reporting on the Antarctic ozone hole in 1985. The Montreal Protocol on Substances that Deplete the Ozone Layer was adopted on 16 September 1987 at the Headquarters of the International Civil Aviation Organization in Montreal. The Protocol came into force on 1st January 1989, when it was ratified by 29 countries and the European Economic Community. To date 189 out of 193 United Nations members have ratified it.
The Protocol was designed so that schedules for reducing and phasing out the production and import of ozone-depleting substances could be revised on the basis of periodic scientific and technological assessments. Following such assessments, the Protocol was adjusted to accelerate the phase out schedules. It has also been amended to introduce other kinds of control measures and to add new controlled substances to the list.
The Secretariat for the Montreal Protocol 
is based at the United Nations Environment Programme.