"This is the first time the issue of exemptions on methyl bromide has ever been taken up," Milton Catelin, chairman of the Open-Ended Working Group on the Montreal Protocol, told a news conference.

Environment ministers and officials from more than 100 countries are gathering for a two-day meeting in the capital Colombo to review the 1987 Montreal Protocol on ozone depleting substances. The meeting will be formally inaugurated on Thursday.

While developed countries have until 2004 to phase out methyl bromide, developing countries have 10 years longer.

About 70,000 tonnes of methyl bromide are used each year, mostly in developed countries.

The Montreal protocol requires its more than 170 signatory states to phase out the use of some 95 chemicals that damage the ozone layer, a stratum of the atmosphere that protects the earth from ultra violet radiation which can cause skin cancer.

Catelin could give no details of how long the exemptions would be, but said all applications would be subject to a strict review process.

"An exemption will be granted only if there are no viable alternatives for a particular industry in a particular country," he said.

Catelin said a mechanism to review applications for exemptions was discussed yesterday by several representatives including those of the United States, Canada, Japan and the European Union.