Scientists Joe Farman, Brian Gardiner, and Jon Shanklin at the British Antarctic Survey published shocking results regarding ozone concentrations above Halley Bay near the South Pole in May 1985. Their data showed abnormally low levels of ozone that defied previous models of atmospheric behavior.
Non-Article 5 parties froze production and consumption of Group I substances at 1986 base levels starting the 1st of July 1989. These nations achieved a 75% phasedown by 1994 and complete elimination by 1996.
Pledges amounting to US$3.1 billion were made over the period from 1991 to 2005 to finance technology transfer. One hundred forty-seven of the 196 Parties to the treaty meet these criteria and are known as Article 5 countries.
A study detected fresh atmospheric releases of carbon tetrachloride from China's Shandong province beginning sometime after 2012. Scientists monitoring the atmosphere reported evidence of continuing industrial production of CFC-11 following the 2010 phaseout date.
Developing nations completed their halon phase-out by 2010 after freezing production in 2002. Halons used in fire suppression systems followed similar schedules, with developed nations freezing output in 1992 and eliminating them by 1994.