Half of all dental amalgam is comprised of mercury. Waste amalgam is created when new fillings are inserted and/or old fillings are removed. When material containing mercury is washed down the drain or thrown into the trash, mercury can be released into our air and water and can pose a threat to our health.

Why is mercury a problem?

Mercury that is released into the environment can be transformed through biological processes into methyl mercury, a form of mercury that "bioaccumulates" in the tissue of fish to levels that are 100,000 times higher than those in the water that they inhabit, making them unhealthful or dangerous to eat. Methyl mercury is highly toxic to developing nervous systems.

For these reasons, the Massachusetts Department of Public Health (DPH) has advised pregnant women, nursing mothers, women of child-bearing age and children under 12 to avoid eating native freshwater fish from any Massachusetts lakes, rivers and streams. DPH has also recommended that everyone limit their consumption of certain marine species and avoid certain fish from those bodies of water where sampling has revealed a significant mercury problem.

The Massachusetts Executive Office of Environmental Affairs has adopted a Zero Mercury Strategy, which is designed to virtually eliminate mercury use and releases to the environment. The Strategy focuses on reducing mercury air emissions and wastewater discharges from Massachusetts incinerators and other businesses, and on educating consumers so they can recycle products containing mercury (and buy non-mercury alternatives). Already, mercury emissions in Massachusetts have been cut in half from the high levels recorded in 1996.

How do dental offices contribute to this problem?

Dental offices contribute an estimated 13 percent of the mercury released to Massachusetts waters, primarily through wastewater discharges. Dental offices can release mercury to the environment through wastewater (as drains discharge to sewers or septic systems) and through trash that includes products containing mercury (e.g., amalgam scraps).

How can dentists be part of the solution?

You should keep mercury out of your wastewater and trash! To do so, you need to know what products and waste materials contain mercury and how to handle them appropriately.

Know what products in your office contain mercury:

  • Bulk mercury, formerly used to prepare dental amalgam.
  • Excess pre-packaged amalgam.
  • Mixed amalgam with tooth scraps.
  • Residual mercury in wastewater from dental offices, which can include mercury dissolved in rinse water as well as fine particles of mercury-containing amalgam that do not get captured by an evacuation trap, filter or screen.
  • Other products containing mercury, such as fluorescent lights, thermometers, sphygmomanometers, etc.

One important way to help reduce mercury pollution is to use non-mercury products or products with reduced mercury content where possible. Another is to recycle mercury-containing products at the end of their useful lives.

Collect mercury-bearing wastes and recycle them:

  • Carefully collect excess amalgam and store it in airtight containers. Send it to a recycler when the container is full.
  • Use an evacuation trap to capture scrap amalgam. The traps can be recycled with their contents (and replaced with new ones periodically), or you can use a reusable trap. When cleaning traps, filters, and screens, be careful not to wash scrap amalgam down the drain or throw it in the trash.
  • Use an advanced amalgam separator to further reduce the discharge of mercury into wastewater.
  • Recycle your remaining supply of bulk mercury.
  • Recycle other mercury-containing products rather than throwing them into the trash.

Know your regulatory status and responsibilities:

At this time, we do not have sufficient information to know how much mercury leaches from dental wastes to definitively classify these wastes as hazardous or non-hazardous. Therefore, MassDEP recommends that any waste containing mercury be handled as if it is "hazardous," to ensure that mercury is not released to the environment. Hazardous wastes are regulated by MassDEP to ensure their safe handling and disposal.

  • Very Small Quantity Generators (VSQGs): Dental offices that generate less than 100 kilograms of wastes containing mercury in a month are considered to be VSQGs. State regulations (310 CMR 30.000) provide several options for recycling wastes from these generators. VSQGs must properly identify their waste, store it properly, and send it offsite to an authorized recycling, treatment, storage or disposal facility. As long as dental offices that are VSQGs comply with these requirements, they are exempt from regulation by the U.S. Environmental Protection Agency.
  • Small Quantity Generators (SQGs) and Large Quantity Generators (LQGs): Dental offices generating between 100 and 1,000 kilograms of wastes containing mercury in a month are regulated as SQGs. LQGs are those who produce more than 1000 kilograms per month. While there are few if any dental practices that fall into these categories, those that do must comply with the full spectrum of state and federal hazardous waste management rules.

The Massachusetts Hazardous Waste Management Act (MGL c. 21C) and federal law make all generators responsible for knowing whether their waste is hazardous or not. This decision can be made by testing a waste or by relying on testing conducted by other parties (e.g., a waste treatment technology vendor).

What rules apply to management of mercury-bearing dental wastes?

Recycling Rules: Dentists can recycle mercury-bearing wastes under MassDEP "Class A Recycling Rules" (310 CMR 30.200). To recycle your mercury-bearing waste, you will need to send your mercury-bearing waste to an authorized recycler who has obtained a "Class A recycling permit" from MassDEP (or, if the facility is located outside of Massachusetts, has an equivalent permit from the state it is located in). You may use a common carrier for these shipments. Your shipment should be packaged carefully and labeled properly, and you should keep a record of each shipment. Your recycling facility and/or hauler can assist you with the necessary records, packaging and labeling.

Currently, you also need to file a "Class A permit notification with MassDEP, pay a permit fee, and file an annual report of your recycling shipments. To promote recycling, MassDEP plans to amend its recycling rules in Spring 2002. The proposed changes are expected to eliminate the Class A permit, permit fee, and annual reporting requirements.

Disposal Rules: If you do not recycle, you should send your mercury-bearing waste to a hazardous waste facility for disposal. You should comply with the requirements of 310 CMR 30.353:

  • Register with MassDEP as a Very Small Quantity Generator;
  • Use U.S. Department of Transportation-approved containers for waste accumulation and transportation;
  • Mark and label containers as hazardous waste;
  • Arrange to have the waste shipped to a licensed hazardous waste facility by a licensed hazardous waste transporter, or transport your waste yourself to another generator or a hazardous waste facility;
  • Maintain records of the quantities of hazardous waste you accumulate and ship offsite for disposal; and
  • Use a hazardous waste manifest or bill of lading to document your shipment.

Who Can Help?

There are several companies that provide mercury waste handling, disposal and recycling services. MassDEP maintains a list of service providers.

For more information: