WASHINGTON – The United States will eventually stop all exports of elemental mercury, a neurotoxin harmful to humans, under legislation sponsored by Democratic presidential nominee Sen. Barack Obama and signed into law by President Bush on Tuesday.

Under the legislation, S 907, the ban on the federal sale and export of elemental mercury will take place immediately. All exports of the substance will be banned as of Jan. 1, 2013. The act provides for a long-term management and storage option for elemental mercury generated by the private sector as of 2010.

Elemental mercury, a dense, shiny, silver-colored metal, is the pure form of mercury. There are also inorganic mercury compounds used in fungicides and antiseptics and organic mercury compounds such as methylmercury.

The United States is one of the world’s biggest exporters of mercury and the export ban would have a notable effect on the market availability of mercury.

Elemental mercury can be found in thermometers, barometers, dental amalgams and batteries. While the U.S. mining and manufacturing industries have developed alternatives, mercury is a major source of pollution, especially in developing countries where it is used in mining operations and industrial processes.

Mercury is particularly harmful to pregnant women, newborns and children. When ingested, it can lead to learning disabilities and physical ailments. As many as 630,000 children born each year in the United States are at risk of neurological problems related to mercury.

The bill, Obama said after it cleared Congress in late September, “Will protect millions of the world’s vulnerable citizens, particularly pregnant women and children, from the deadly threat of mercury poisoning.”

Obama sponsored the bill with Sens. Lisa Murkowski, R-Alaska, and Barbara Boxer, D-Calif. Rep. Tom Allen, D-Maine, was a main sponsor in the House.