Consumers who want to be sure they are not buying aerosols that damage the ozone layer no longer need worry.

Yesterday, the annual International Day for the Preservation of the Ozone Layer, the United Nations announced that the ban on using materials harmful to the ozone layer is the first ecological treaty to be ratified by every country in the world.

The news came after the Pacific nation of Timor-Leste announced it had also ratified the treaty, known as the Montreal Protocol.

However, ozone-thinning materials can be found in some products in daily use. The Environmental Protection Ministry here still allows materials to be imported, among other uses, for cooling systems, to fill and inflate mattresses and as insulation.

Use of these materials is to be greatly reduced as well.

The UN's EnvironmentProgram announced yesterday that some 100 ozone-damaging materials have so far been banned from use.

Had the ban not been put into effect, their presence in the atmosphere would have grown 10-fold by the middle of this century, causing an estimated 20 million people to have skin cancer and harm the eyesight in another 130 million people. But it will take four decades for the ozone layer to be fully restored.

Before the first signing of the Montreal Protocol in 1987, the ozone layer thinned so much, the famed hole in it was created over Antarctica.

Israel plays a central role in the ozone issue, as the Bromine Compounds firm in Ramat Hovav in the Negev is a major producer of methyl bromide, a pesticide and a powerful ozone-thinning compound.

It is essential for crops and is being phased out only gradually.

"The quantities of methyl bromide in Israel have been greatly reduced in recent years," Ronny Seri, of the Environmental Protection Ministry's air quality division, said yesterday. "We have a permit to use it for what is defined as critical use, including fumigating soil for crops such as strawberries."

However, Seri said use of methyl bromide for this purpose fell by 83 percent since 1991.

The focus of the fight to save the ozone layer has been various aerosols containing gases like freon, and it won't be found any more in such sprays. The ozone layer filters the sun's ultra-violet rays and is thus critical for life to survive on earth.

Protecting the ozone layer also helps fight global warming, as some of the materials in question act as greenhouse gases. According to the UN, the reduction in ozone-thinning materials has slowed the increase in global warming by years.