Managing Dental Mercury
Effective March 16, 2003, New York State Law requires that all dentists recycle mercury and mercury amalgam waste generated in their practices. The law also requires that dentists use encapsulated mercury and prohibits, in the practice of dentistry, the use or possession of elemental mercury not in capsules. Effective May 12, 2006, dental facilities are required to install amalgam separators that remove waste amalgam from the dental facilities' wastewater.
A list of amalgam separator manufacturers is available. This is an informational list and is not endorsed by the Department. Specific regulatory requirements are provided under Subpart 374-4 (link leaves DEC). Multiple questions dental facilities may have concerning the installation of amalgam separators are also addressed.
Elemental Mercury (also referred to as free, bulk, or raw mercury)
In the event that elemental mercury is present in your dental office:
- Recycle all elemental mercury. Many hazardous waste haulers and dental amalgam recyclers will accept elemental mercury for recycling.
- Never rinse elemental mercury down the drain.
- Never dispose of elemental mercury in the trash.
- Never dispose of elemental mercury in the sharps container or as medical waste.
- If only a small amount of elemental mercury is to be recycled, it may be possible to initiate a reaction with an amalgam alloy to form scrap amalgam, which must then be recycled through your amalgam recycler.
Some solid waste planning units (such as in Erie, Monroe, Otsego, Rockland, Oneida-Herkimer and Cayuga Counties) offer elemental mercury recycling programs, which allow dentists to safely manage their elemental mercury. Some will charge a fee for this service. Call your local solid waste district to inquire about such programs. A list of New York State recycling coordinators.
If you are concerned about the possible uncontained presence of mercury in your dental office due to historical or recent mercury spills, equipment is available for the detection of mercury vapor and mercury spill locations in the workplace environment. This equipment can be rented from rental test equipment companies.
If your dental practice continues to utilize dental amalgam, New York State Law requires the use of single-use amalgam capsules. This minimizes the chance of accidental mercury spills.
Minimize the generation of amalgam waste. Don't mix a double-use capsule if a single-use capsule will do. Less waste means less amalgam that needs to be recycled.
In the event of a mercury spill, put on disposable nitrile gloves and immediately clean up the spill utilizing a mercury spill kit. Do not use latex gloves as mercury can penetrate latex. Mercury spill kits are available from a number of sources including: companies that specialize in Occupational Safety and Health Administration (OSHA) compliance supplies and equipment; amalgam recyclers; and dental product suppliers. Before purchasing a kit, make sure it comes with complete instructions on how to perform a spill clean up. Train several staff members in proper spill clean up procedures.
- Never put scrap amalgam in the sharps container.
- Never put scrap amalgam in the red biohazard bag.
- Never discard scrap amalgam in the trash.
- Never rinse scrap amalgam down the drain.
- Never remove excess amalgam from the amalgam well with the high-speed suction vacuum line.
- Never clean up a mercury spill using a vacuum cleaner.
- Never place extracted teeth with amalgam restorations in the red biohazard bag. They should be placed in a container that is acceptable to your recycler. Precautions, such as glasses, gloves, and mask, should be used when handling extracted teeth.
Recycling Scrap Amalgam
- Collect and store all contact and non-contact scrap amalgam, capsule waste and extracted teeth with amalgam restorations in separate, appropriately labeled, tightly closed containers.
- Recycle scrap amalgam through an amalgam recycler.
- Do not use heat. If contact amalgam must be disinfected before shipment to your recycler, do not use any method that utilizes heat. The heat will cause the mercury to volatilize and be released into the environment.
- Do not decant liquid. If you store scrap amalgam under used radiographic fixer, water, or other liquid, do not, under any circumstances, decant the liquid down the drain. Contact your dental amalgam recycler or hazardous waste hauler for more information on how to dispose of this material properly.
The control of waste dental amalgam includes proper management of the traps and filters used in your office vacuum system. Disposable amalgam traps are preferable to reusable traps because of the difficulty in effectively removing amalgam particles from the trap without spilling the particles into the drain or garbage. In addition, consider replacing size 40 mesh traps with size 100 mesh traps if your suction system can function adequately with the smaller mesh. Although finer screens may be more effective at trapping amalgam particles, they may require cleaning and changing more often.
Check with your dental amalgam recycler to determine if disposable amalgam traps are accepted. Disposable amalgam traps should not be placed in the regular garbage or with medical waste and must also be sent for recycling.
Precautions, such as glasses, gloves and mask, should be used when handling the chair-side trap. These traps should be changed as often as necessary.
The vacuum system should be flushed with disinfecting line solution before changing the chair-side trap. Research has suggested that some types of line cleansers, such as those that contain bleach, may dissolve mercury from amalgam particles. This would increase the release of mercury into the dental wastewater.
According to the American Dental Association, the following line cleansers do not contain bleach or chlorine and do not appear to dissolve mercury from amalgam. This is an informational list and is not endorsed by the Department or the American Dental Association. You should check with your equipment manufacturer to determine the appropriate line cleanser for your equipment:
- Biocide (Biotrol International)
- BirexSe (Biotrol International)
- DRNA Vac (Dental Recycling North American, Inc.)
- E-Vac (L&R Manufacturing Co.)
- Fresh-Vac (Huntington)
- GC Spray-Cide (GC America Inc.)
- Green and Clean (Metasys)
- Microstat 2 (Septodont USA)
- Patterson Brand Concentrated Ultrasonic Cleaner/Disinfectant Solution (Patterson Dental Supply, Inc.)
- ProE-Vac (Cottrell Ltd.)
- Pure-Vac (Sultan Chemists Inc.)
- Sani-Treet Plus (Enzyme Industries Inc.)
- SRG Evacuation (Icon Labs)
- Stay Clean (Apollo Dental Products)
- Turbo-Vac (Pinnacle Products)
- Vacusol Ultra (Biotrol International)
- Cavicide (Metrex Research Corp.)
- Vacuum Clean (Palmero Health Care)
The best method is to flush the line with an appropriate line cleanser at the end of the day. The trap should be changed the next morning before the suction is used. This method will allow the particles in the trap to dry.
An alternative method is to flush the system with a cleaning solution according to the product's directions. The lid may then be removed from the trap. This allows air to pass through the trap until the contents are dry (usually not more than five minutes).
Replaceable Amalgam Traps
Steps to clean this type of trap are:
- Open the chair-side dental unit to expose the amalgam trap.
- Remove non-amalgam fragments such as cement from the trap with cotton forceps and discard in the garbage.
- Remove all visible amalgam by tapping the contents into a properly labeled container. Close the cover tightly.
- If the trap is visually clean, it can be reused. A heavily contaminated trap should always be recycled. Store contaminated traps in the properly labeled container.
Disposable Amalgam Traps
- Remove the amalgam trap and place it in a properly labeled container.
- Do not clean disposable traps under running water or discharge the trapped amalgam into the wastewater system.
- Do not discharge the trapped amalgam into the sharps container, as medical waste, or in the trash.
Vacuum Pump Filters (by the central suction pump)
- Replace vacuum pump filters regularly as recommended by the equipment manufacturer.
- Remove the filter. While holding it over a tray or other container that can catch spills, decant as much liquid as possible without losing visible amalgam. The decanted, amalgam-free liquid can be rinsed down the drain.
- Put the lid on the filter and place it in the box in which it was originally shipped. When the box is full, the filters must be recycled. Be sure to check with your amalgam recycler to ensure that they will take these filters.
- Do not dispose of used vacuum pump filters in the sharps container, as medical waste, or in the trash.
Dental amalgam separators will remove the maximum amount of amalgam waste and are much more efficient in removing amalgam from the dental wastewater than filters and traps used in chair-side dental units and vacuum lines. Most amalgam separators can attain an efficiency of 99 percent removal of amalgam.
An amalgam separator must be installed in dental facilities where dental amalgam is applied, altered, maintained, removed, disposed, generated or where elemental mercury is used or possessed by licensed dentists. An amalgam separator must treat all dental facility waters likely to come into contact with dental amalgam waste prior to discharge. This includes wastewater from chair-side water collection units as well as sinks and drains.
The only dental facilities not required to install an amalgam separator are specialties where orthodontics, periodontics, prosthodontics and oral and maxillofacial surgery are exclusively performed.
Although the department does not endorse any specific amalgam separators, a list of dental amalgam separator companies is available. The following criteria should help you select the right system for your facility:
- The system must be effective. The manufacturer must be able to prove that the system can remove the amalgam from the wastewater regardless of particle size. An amalgam separator placed into service after May 12, 2006 must achieve 99 percent removal efficiency.
- The separator must be properly sized for the volume and flow of the dental facility amalgam wastewater in accordance with the manufacturer's specifications and recommendations. The maximum allowable flow rate through the amalgam separator may not exceed the maximum flow rate capacity that the separator was tested at and passed in meeting International Standards Organization (ISO-11143).
- Available space for the installation and subsequent access to that space for equipment replacement and maintenance should be considered.
- There should be no compromise in suction power.
- You may want to consider a unit that is hands-off. The dentist or staff should not have to perform a series of manual operations or be required to handle and change filters.
- The captured amalgam must be recycled. Consider a company that both sells the system and arranges for the recycling of the captured amalgam. You should, at minimum, request information from the company that sold you the unit about how to assure that the captured amalgam is recycled.
- Simplicity of design is a plus. There will be fewer chances for something to go wrong.
- The unit should operate quietly.
- The unit should come with a fail-safe mechanism that protects you from a spill or back-up in the event that a blockage occurs.
- The unit should install centrally so that the appropriate wastewater streams pass through it before discharging into the sewer system.
- The unit should be reasonably priced. Obtain information from the companies on both short and long term costs (including maintenance and parts replacement) over a five to ten year period before making a decision.
Plumbing Replacement and Repairs
Mercury from prior dental procedures often settles at low points in the plumbing such as sink traps and sumps. The slow dissolution of the mercury in a sink trap or sump can release mercury into the wastewater for years after past disposal practices have been corrected. When there is a possibility that plumbing repairs or demolition may disturb adhered amalgam waste, dental offices should follow common sense approaches and guidelines to protect the environment and those working in the dental facility. For instance, you should advise your plumber that whenever plumbing parts are removed or cleaned, caution should be taken to avoid spilling the contents in case amalgam or mercury are present. The sludge from the pipes should be poured or brushed out and handled as contact amalgam. The plumbing parts can then be put back in place or recycled.
Additional Sources of Mercury in Dental Offices
Electrical equipment with switches, relays or temperature controls (thermostats) may contain mercury and should be properly recycled when replaced.
Mercury thermometers and blood pressure units are also sources of elemental mercury. The following steps should be followed in the event that one of these items break:
- Put on nitrile gloves. Do not use latex gloves as mercury can penetrate latex.
- Clean up all visible elemental mercury using a mercury spill kit. Mercury spill kits are available from a number of sources including: companies that specialize in Occupational Safety and Health Administration (OSHA) compliance supplies and equipment; amalgam recyclers; and dental product suppliers. Before purchasing a kit, make sure it comes with complete instructions on how to perform a spill clean up. Train several staff members in proper spill clean up procedures.
- Place all contaminated items (materials used during the clean up procedure and broken pieces of glass) in a sealable plastic bag or container. Label the bag or container as "Mercury Waste".
- Dispose of all contaminated materials through a hazardous waste hauler.
- Never dispose of mercury contaminated waste in the sharps container, as medical waste, or in the trash.
- Never dispose of elemental mercury down the drain or in the sharps container, as medical waste, or in the trash.
- Consider replacing mercury-containing equipment with non-mercury containing alternatives. Non-mercury containing products are usually available for many of these products at cost-competitive prices.
Alert renovators to the possibility of historical mercury spills that may have resulted in the presence of mercury in carpets, floor cracks, behind mouldings and other areas where elemental mercury may have been used or where amalgam capsules may have been spilled.
The above procedures were adapted for New York State's use from "The Environmentally Responsible Dental Office: a Guide to Proper Waste Management in Dental Offices", prepared by the Northeast Natural Resource Center of the National Wildlife Federation and the Vermont State Dental Society, June 1999.
Additional information may be obtained by contacting the New York State Department of Environmental Conservation, Bureau of Waste Reduction & Recycling at (518) 402-8706 or by e-mail at: [email protected]