However, the environmental lobby is unlikely to regard the talks as their finest hour as not only did the Americans pull out on the first day, but they also failed to get substances such as chromium included in the final plan.

Under the ‘Aarhus Convention’, which countries hope to sign next year, states will establish national registers of industrial pollutants entering the soil, air and water. The outcome of two years of negotiation, the treaty covers the disposal, storage, recycling or treatment of dangerous materials ranging from minerals to hydrocarbons.

But from the outset, this week’s conference - the last of seven before the protocol is ratified in May 2003 - was dogged by controversy. Somewhat surprisingly, the US delegation withdrew not because it thought the proposals were too stringent, but because they did not go far enough. A particular objection was the proposal made by several European states that the system should take the form of a general waste report, as opposed to one that records specific pollutants.

With its powerful chemicals industry, Germany was among the countries pushing hardest for the weaker protocol and with the Americans now out of the way, it is expected that their viewpoint will hold sway when the talks end tomorrow. Other countries, particularly from the former Soviet bloc, balked at how much the more stringent plan would cost to enforce.

The withdrawal of the US delegation came as a particular blow to the environmental lobby, as the US already has a well established system of pollution reporting under its Toxic Release Inventory. This effectively makes the US Environmental Protection Agency database freely available to the public and contains information on releases of some 650 chemicals and chemicals categories.

The protocol will be formally ratified by environment ministers from the ECE’s European region in the Ukrainian capital of Kiev in May.