The new substances, such as n-propyl bromide and halon-1202, which are being used as replacements for chemicals which have been phased out under 1987’s Protocol on ozone-depleting substances, have been indicated in studies to have the potential to damage the ozone layer. Although the quantities being manufactured are at the moment believed to be small, scientists at universities and institutes around the globe, along with UNEP researchers, are concerned that over the coming years they may be produced in ever increasing quantities.
The UNEP has estimated that the ozone layer and the ozone hole over Antarctica, which so far this September is extending over 24 million square kilometres (9.4 million sq miles), or an area about the size of North America, will recover by 2050, as a result of the banning and phasing out of existing, long lived, ozone-depleting chemicals such as chlorofluorocarbons (CFCs). These were widely used in products such as hair sprays until outlawed by the Montreal Protocol. However, the UNEP, is now concerned that the emergence of these new chemicals could significantly delay this recovery date.
“The Montreal Protocol has been a success story of which we can all be proud,” commented the UNEP’s Executive Director, Klaus Toepfer, on International Ozone Day, on 16 September. “Ninety-six ozone-damaging chemicals have been banned or are being phased out…but we must remain vigilant if our success story is to ultimately have a happy ending. Some of these new, replacement chemicals may prove to be no threat at all to the ozone layer although they may pose threats to human health, wildlife and the environment generally. Others, however, may have the potential to cause significant damage to stratospheric ozone, undermining our efforts to date,” Toepfer said.
At least four new substances with a potential to damage the ozone layer have been identified so far, but UNEP warns that not only could there be many more, but each new chemical can have up to 15 different names, making it difficult to monitor and track them in international trade. The four known chemicals are:
- hexachlorobutadiene, which has an ozone-depleting potential (ODP) higher than some ozone-damaging substances that are already banned under the Montreal Protocol and is used as a solvent. The chemical is produced as a by-product of chlorinated chemical production such as the manufacturing of vinyl chloride and has been classified as a high-volume production chemical by the Organization for Economic Cooperation and Development (OECD), with one country reporting that its factories were now producing more than 10,000 tonnes annually. A Canadian Government report has concluded that hexachlorobutadiene has “the potential to contribute somewhat to the depletion of stratospheric ozone”;
- n-Propyl Bromide, which the Technology and Economic Assessment Panel of the Montreal Protocol warns could be as damaging as substances that are already banned or subject to phase-outs, but which is being aggressively marketed as a solvent, a feedstock and as a carrier and intermediate for pharmaceutical and other industries. Between 5,000 to 10,000 tonnes of this substance are being used and emitted annually, with estimates that by 2010, emissions are likely to rise to between 20,000 and
60,000 tonnes as industries switch from banned substances to this one;
- 6-bromo-2-methoxyl-naphthalene, the effects of which are little known a little-known, but which is currently being used in the manufacture of methyl bromide; and
- halon-1202, which is extremely effective for putting out electrical fires and is being used by the armed forces in some countries, but which new research indicates may be long lived and having a higher potential to deplete the ozone layer than some banned substances.
UNEP is urging countries to carry out scientific assessments of these new chemicals and to ban those that are shown to have real ozone-depleting potential. It also wants to see a long-term strategy developed between governments, industry and organizations, involving a voluntary agreement for companies to test and assess a new chemical for its ozone-damaging potential, presenting their findings to Governments before manufacturing and marketing the new substance.
Besides new substances entering the market, UNEP warns that the phase out of existing chemicals, identified as damaging the ozone layer, is far from complete. Hydrochloroflourocarbons (HCFCs) will not be fully phased out until the year 2030 and methyl bromide is not due to be fully phased out until 2015. Meanwhile, smuggling of banned substances is continuing, with a recent report in the Japan Times stating that more than 100,000 bottles of CFC-12, banned in industrialised countries in 1996, have been circulating in Japan.