PUNTA DEL ESTE, Uruguay — The United States is looking to join an international treaty phasing out a dozen of the world's most hazardous pesticides and chemicals next year, a U.S. official said as delegates from 130 nations met.

The United States, along with Russia, is the biggest industrialized country that has yet to ratify the Stockholm Convention on Persistent Organic Pollutants -- a United Nations-sponsored treaty seeking to severely restrict 12 chemicals commonly known as the "dirty dozen."

Delegates opened high-level talks Thursday in this Atlantic Ocean beach resort on ways to eliminate toxins and narrow loopholes for a few countries still allowed to use some dangerous chemicals.

"Our hope is that next year we will be a party to the treaty," said Claudia McMurray, deputy assistant secretary for environment, speaking Thursday on the sidelines of the first U.N. meeting on ways to implement the treaty. "It's a pretty aggressive schedule but that's what we're shooting for."

U.S. President George W. Bush, who has faced heavy criticism for his environmental policies, hailed the treaty as a major breakthrough in a pre-Earth Day speech four years ago.

Nonetheless, disagreements in the U.S. Congress over how more toxic chemicals might be added to the ban in the coming years has slowed U.S. ratification, McMurray said.

In May 2001, the United States and 90 other countries signed the treaty, originally negotiated under the Clinton administration. But U.S. ratification has since stalled as the treaty took effect in May of last year.

Some 98 countries have ratified the convention that calls on countries to stop production, sale, and use of the substances, many of them found in poisons used to fend off or kill mosquitoes, termites and other insects found on crops or in homes.

Among them are Polychlorinated Biphenyls, or PCBs, dioxins, and DDT. Others include furans and the pesticides aldrin, hexachlorobenzene, chlordane, mirex, toxaphene, dieldrin, endrin and heptachlor.

Scientists say the toxic chemicals tend to persist in the environment and travel long distances, posing significant health risks, including birth defects in humans and animals. The chemicals tend to accumulate in the bodies of both humans and animals and have been also linked to cancer and other diseases.

U.N. officials estimate the process to eliminate the chemicals -- known as Persistent Organic Pollutants, or POPS, and replace them with new technologies or other methods could cost billions of dollars.

The use of DDT to combat malaria in Africa, for example, has been allowed, until a safer means to control the disease can be developed.

Another priority for delegates is establishing a framework for adding new and potentially dangerous chemicals.

In the United States, the chemicals have been banned from production for use, but U.S. chemical manufacturers are not prevented from exporting them.

Clifton Crutis, director of the global toxics program at the World Wide Fund, said he hoped the Bush administration moves swiftly to ratify the treaty after years of delays.

"The United States has been one of the most advanced countries in setting regulatory standards for chemicals," he said. "It's hard to believe that they are not a party to this treaty."

Source: Associated Press