EPA today announced it intends to propose a rule to reduce mercury waste from dental offices. Dental amalgams, or fillings containing mercury, account for 3.7 tons of mercury discharged from dental offices each year. The mercury waste results when old mercury fillings are replaced with new ones. The mercury in dental fillings is flushed into chair-side drains and enters the wastewater systems, making its way into the environment through discharges to rivers and lakes, incineration or land application of sewage sludge. Mercury released through amalgam discharges can be easily managed and prevented.

EPA expects to propose a rule next year and finalize it in 2012. Dental offices will be able to use existing technology to meet the proposed requirements. Amalgam separators can separate out 95 percent of the mercury normally discharged to the local waste treatment plant. The separator captures the mercury, which is then recycled and reused.

Until the rule is final, EPA encourages dental offices to voluntarily install amalgam separators. Twelve states and several municipalities already require the installation of amalgam separators in dental offices.

Approximately 50 percent of mercury entering local waste treatment plants comes from dental amalgam waste. Once deposited, certain microorganisms can change elemental mercury into methylmercury, a highly toxic form that builds up in fish, shellfish and animals that eat fish.

Fish and shellfish are the main sources of methylmercury exposure to humans. Methylmercury can damage children’s developing brains and nervous systems even before they are born.