Ozone-protection treaty strengthened.

Representatives of more than half the world's nations met in Copenhagen last month to revise the Montreal Protocol, an international ozone-protection treaty The compromise recommendations they agreed to on Nov. 25 would accelerate the phaseout of previously targeted ozone-destroying pollutants, such as chlorofluorocarbons (CFCs), and initiate the treaty's regulation of three additional chemicals.

A progressive erosion of Earth's ozone layer by several major classes of industrial pollutants seriously threatens the ability of Earth's upper atmosphere to filter out the sun's biologically harmful ultraviolet radiation. But "nature and man can cooperate, because the ozone layer will repair itself when we halt the destruction of it," said Denmark's environment minister, Per Stig Moller, who hosted the conference.

Provisions agreed to in Copenhagen would seek to help preserve the ozone layer by:

* Phasing out production of CFCs and carbon tetrachloride by Jan. 1, 1996 -- four years earlier than now required.

* Banning halons, fire retardants used in many fire extinguishers, by 1994, six years early

* Ending production of methyl chloroform, a dry-cleaning agent, by 1996, nine years early

* Initiating controls on hydrochlorofluorocarbons (HCFCs). In 1996, the treaty would freeze consumption of these CFC substitutes at 1991 levels, with a promise to eliminate them by 2030.

* Drafting initial controls on hydrobromofluorocarbons (HBFCs). Both production and use of these fire retardants would be eliminated by the end of 1995.

* Beginning a review of the risks posed by methyl bromide, a widely used fumigant pesticide, to be completed by 1995. A freeze -- at 1991 production levels -- would begin that same year. Though this chemical poses a potentially serious threat to ozone, its relatively short life makes its atmospheric levels fairly responsive to altered patterns of use.

* Agreeing to maintain a multilateral fund beyond 1993. Opened with money from industrial nations last year, this bank account has taken in at least $73 million for the financing of ozone-friendly industrial development in Third World countries. Last month, delegates agreed to increase the fund's capitalization to between $340 million and $500 million by 1996.

Earlier this year, in response to data forecasting a possible Arctic ozone hole similar to the one that now forms annually over the Antarctic, the United States volunteered to accelerate its phaseout of chemicals regulated under the Montreal Protocol (SN: 2/15/92, p.102). However, it left open a big loophole: Companies could produce the banned chemicals indefinitely for "essential uses and for servicing certain existing equipment." Delegates in Copenhagen agreed to the same exceptional-use provisions, says Dan Strub of Friends of the Earth in Washington, D.C.

To date, 92 nations have ratified the Montreal Protocol. Together, these countries produce and consume virtually all the pollutants being regulated under the treaty.