The UN said Thursday an insecticide used in farming and to treat woodworm, Lindane, was among nine highly toxic chemicals added to a "dirty dozen" of dangerous substances on an international red list.
The eight others added to the Stockholm Convention under changes that came into force on Thursday are also used commercially in some countries as pesticides or industrial flame retardants, the UN Environment Programme said in a statement.
The Stockholm Convention bans or restricts hazardous pesticides and industrial chemicals that can kill, damage the nervous and immune systems, cause cancer and reproductive disorders or interfere with normal child growth.
The 2001 treaty, ratified by 170 nations, originally covered 12 chemicals known as Persistent Organic Pollutants (POPs) because they do not break down over time in the environment and accumulate in soil, water, the food chain and in human tissue or organs such as the liver.
Lindane, which has toxic effects in laboratory animals and aquatic organisms, will be authorised solely for pharmaceutical use to treat head lice and scabies, the UNEP said.
"By extending for the first time the scope of coverage of the Stockholm Convention, governments have strengthened efforts to protect human health and raise chemicals issues to the top of the global agenda," said Donald Cooper, executive secretary to the Stockholm Convention.
Eight of the new chemicals were classified under Annex A which bans or phases out their production.
One of new group is chlordecone, a pesticide which was banned in France in 1993 after being used widely in banana plantations in the French Antilles.
A chemical incorporated in some plastics, perfluorooctane sulfonic acid, was also restricted, with exemptions in making flat screens, computer semiconductors and for some types of ant and termite control.
Some countries have already banned or restricted the sale of the chemicals.
Explore further: UN: Treaty expanded by 9 more dangerous chemicals