New EPA Rule on Mercury Fillings Leaves Some Grinning

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By Amena H. Saiyid

Mercury-laden fillings from dental offices that have sometimes ended up being flushed down the drain won’t be regulated as industrial releases of pollution under a new Environmental Protection Agency final rule.

The final dental amalgam rule (RIN:2040-AF26) does require dental offices to install amalgam separators—devices designed to remove mercury and other metals from wastewater. Dentists also must make sure they don’t flush scrap from mercury fillings down drains, and must clean water lines using oxidizing cleaners. All three steps are already voluntary guidelines of the American Dental Association.

Significantly, the final rule does not require wastewater utilities to monitor and report on the more than 100,000 dental offices that fall under the EPA’s jurisdiction.

The EPA rule requires just a one-time certification from the dental offices that the amalgam separator is installed, Cynthia Finley, regulatory affairs director for the National Association of Clean Water Agencies, told Bloomberg BNA in a Dec. 16 telephone interview.

‘We Are Very Happy’

“We were very happy to see EPA removed the dental sector from categorical industrial users and significant industrial users because it helps reduce the burdens on publicly owned treatment plants,” said Finley.

Mercury-laden dental amalgams, or silver filling as they are commonly known, is a material used to fill cavities, though its use is fading because of concerns about mercury, a known neurotoxin.

The final rule applies to publicly owned wastewater treatment plants, which must ensure that the wastewater they receive directly from industrial plants and factories is pretreated to effluent limits set by the EPA.

A ‘Reasonable Approach’

Claudio Ternieden, government affairs director for the Water Environment Federation, said the EPA rule allows flexibility to wastewater treatment plants that have to enforce the rule.

The EPA recognized that dental offices discharge significantly less quantities of pollutants as well as volumes of wastewater than industries regulated under categorical pretreatment standards, the agency said.

The American Dental Association called the rule a “reasonable approach” for capturing mercury from amalgam before it escapes into the sewer systems.

Avoiding Patchwork Regulations

“We believe this new rule—which is a federal standard—is preferable to a patchwork of rules and regulations across various states and localities,” said ADA President Gary Roberts in a Dec. 15 statement accompanying the rule’s release.

Roberts was alluding to the 12 states and 18 localities that have adopted standards to regulate dental amalgam discharges.

According to the Food and Drug Administration, about half of a dental amalgam filling is liquid mercury and the other half is a powdered alloy of silver, tin and copper. Mercury is used to bind the alloy particles together into a strong, durable and solid filling. The International Academy of Oral Medicine and Toxicology released a study in October that found dental amalgam fillings containing mercury to be dangerous.

The pretreatment rule complies with Section 304 (a) of the Clean Water Act. That provision requires the EPA to regulate discharges of pollutants from industries directly to surface waters through effluent limitation guidelines and indirect discharges that first go to wastewater treatment plants through pretreatment standards. Both regulatory limits are based on best available technology.

To contact the reporter on this story: Amena H. Saiyid in Washington at

To contact the editor responsible for this story: Larry Pearl at

For More Information

The EPA final dental amalgam rule is available at

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