U.N. officials say more than 130 nations have adopted the first legally binding international treaty aimed at reducing mercury emissions.
The U.N. Environment Program says the treaty was adopted Saturday morning, after all-night negotiations that capped a week of talks.
The treaty will for the first time set enforceable limits on emissions of mercury, a highly-toxic metal that is widely used in chemical production and small-scale mining.
Joe DiGangi, a science adviser with advocacy group IPEN, says that while the treaty is "a first step," it is not tough enough to achieve its aim of reducing overall emissions.