If we fail with the environmental issues, then all other political work will be pointless

Swedish Prime Minister Goran Persson

They applauded after conference chairman Kjell Larsson, the Swedish environment minister, declared the treaty adopted.

"We must put a stop to the use of poisons which threaten plants, animals and the environment in which we live", said the Swedish prime minister Goran Persson at the opening of the conference.

POPs are found in everything from paint to pesticides and remain in the environment for decades without breaking down.

They are spread by winds and oceans, and have been found everywhere from Antarctica to remote areas of Canada.

They accumulate in fatty tissue and have been blamed for disease and birth defects in humans and animals.

"POPs are a chemical time bomb", Mr Persson said.

DDT exemption

One widely known chemical is DDT, which was originally created to control the spread of malaria during World War II.

The 'dirty dozen'

Aldrin Chlordane DDT Dieldrin Dioxins Endrin Furans Heptachlor Hexachlorobenzene (HCB) Mirex Polychlorinated Biphenyls (PCBs) Toxaphene

Although it is widely banned or restricted, some nations have continued to use it to control insect-borne diseases.

The treaty will allow about 25 countries to continue using DDT to combat malaria in accordance with World Health Organization guidelines, until they can develop safer solutions.

The environmental group Greenpeace has welcomed the treaty, but pointed out that it still has to be ratified by individual parliaments.

It will take effect once 50 countries ratify it.

The treaty aims to control the production, import, export, disposal, and use of POPs.

It has been endorsed by US President George W Bush, giving him an environmental reprieve with European leaders and environmentalists worldwide, who criticised his rejection of the 1997 Kyoto global warming treaty and domestic policies they say favour production over conservation.