Representatives of about 50 countries began new talks Monday on an international convention to control the movement of hazardous waste and limit the dumping of toxic materials in poorer developing countries.

The U.N. Environment Program said legal and technical experts from the 50 countries would work until Nov. 16 on a fourth draft text of the proposed treaty.UNEP, as sponsor of the negotiations, hopes to get a complete text in time for final agreement and acceptance at a ministerial-level conference tentatively scheduled for next March 20-22 in the northern Swiss city of Basel.

So far, the draft comprises 29 articles over 36 pages but is full of bracketed language on which there is disagreement.

"We hope to eliminate many of these brackets and trust that nothing new will be introduced in the draft convention after the current meeting," UNEP legal adviser Iwona Rummel-Bulska said. UNEP Executive Director Mostafa Tolba proposed a preamble under which signatory states would undertake to keep dangerous waste generation to a minimum.