NAIROBI — More than 140 countries agreed Friday to launch negotiations establishing a treaty on mercury to limit pollution affecting millions of people across the world, the UN environment body said.

They also agreed an interim plan to curb pollution while awaiting the treaty because “the risk to human health was so significant that accelerated action … is needed,” the United Nations Environment Programme said in a statement.

“Today we are united on the need for a legally binding instrument and immediate action towards a transition to a low-mercury world,” UNEP chief Achim Steiner said at the end of the body’s governing council meeting in Nairobi.

He added that world ministers who attended the week-long meeting “decided the time for talking was over. The time for action on this pollution is now.”

The interim plan includes boosting countries’ efforts on safe stockpiling of mercury, reducing supply and use among artisanal miners as well as reducing mercury in products such as thermometers.

Mercury is a heavy metal whose highly toxic compounds — propagated notably by the production of coal, certain kinds of plastics and improper disposal of fluorescent light bulbs — poison millions of people worldwide.

Fish-eating is the prime source of exposure among humans. The effects of mercury ingestion include damage to the brain, kidney and lungs.