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Recycling of Mercury By Dentists FAQ

1. Why are mercury and mercury wastes of concern?

Mercury is a highly toxic, persistent and bioaccumulative neurotoxin. Mercury is released into the air through the burning of coal at power plants and the burning of mercury-containing wastes. Mercury is also discharged directly into waterbodies by publicly owned treatment works (POTWs are wastewater treatment plants) or remains in the sludge generated by the treatment plant. Typically, this sludge is composted (resulting in land application) or incinerated causing the mercury to vaporize. Once mercury reaches a water body through rain or snow, bacteria convert it to a more toxic form, methylmercury. Methylmercury accumulates in the tissues of plants, insects, fish, and animals. Mercury releases disperse over a wide area and will remain in the environment for years.

Health concerns arise when humans consume fish and wildlife and the associated health effects may be severe. The developing fetus and young children are especially at risk when exposed to methylmercury. Delayed development, impaired motor function, and impacts on cognitive thinking are associated with methylmercury exposure. In adults, symptoms such as memory loss, fatigue, muscle tremors, skin rashes, and brain/kidney damage may occur depending on the degree of mercury exposure.

2. What does New York State's law require for dentists?

Chapter 506, Laws of 2002, states, "No dentist shall use or possess elemental mercury in the practice of dentistry unless such elemental mercury is contained in appropriate pre-encapsulated capsules specifically designed for the mixing of dental amalgam. All dentists shall recycle any elemental mercury, including any pre-encapsulated mercury capsule waste and dental amalgam waste generated in their dental practices in accordance with rules and regulations established by the commissioner."

6NYCRR Subpart 374-4, Standards for the Management of Elemental Mercury and Dental Amalgam Wastes at Dental Facilities (link leaves DEC) (effective May 12, 2006), requires dental facilities to install dental amalgam separators; recycle dental amalgam waste and elemental mercury; and maintain records on the installed separator and recycled dental amalgam wastes.

3. Why the legislative concern and requirement?

Historically, dentists mixed elemental mercury with amalgam in the dental office to prepare amalgam for use as cavity filler. During the mixing process, excess mercury could easily be spilled exposing the dentist, dental assistants and patients to mercury. This practice has now been replaced by the process of using pre-measured capsules of dental amalgam that are mixed by the dentist just prior to filling a cavity. This is much more efficient, uses a specified amount of mercury, eliminates the need for storing and using additional elemental mercury by the dentist, and reduces the potential for mercury spills and mercury exposure.

The second aspect of the legislation requires that any elemental mercury and excess dental amalgam waste generated by the dentist must be recycled. This was legislated to reduce the risk of mercury entering the environment through wastewater discharges, landfilling or incineration. Presently, the most environmentally responsible action for the management of this material is to recycle it. Recycling is made possible by collecting elemental mercury and dental amalgam waste in proper containers and installing an amalgam separator.

National and regional efforts are under way to establish long-term storage options for the management of elemental mercury and mercury containing wastes; however, those options are not yet fully developed or available.

4. How should dental facilities store and then dispose of leftover encapsulated mercury and mercury amalgam waste?

All elemental mercury, as well as any contact and non-contact amalgam, should be collected and stored in an air-tight, leak-proof and structurally sound container with a label stating the type of the dental amalgam waste contained and the date the waste was initially placed in the container. The containers holding the dental amalgam waste must be tightly closed except when adding or removing dental amalgam waste. A container cannot be stored by the dental facility for more than one year from the date the waste was initially placed in the container.

All dental amalgam waste and elemental mercury generated by the dental facility must be sent for mercury recycling. A few communities in New York State allow dentists to bring mercury waste to their household hazardous waste facilities. Dentists should contact their local solid waste management authority or officials for more information.

Most dentists will hire mercury waste recycling companies to regularly take their waste. These recycling companies will usually provide the proper containers and either pick up the waste or arrange for its shipping.When the waste is picked up by a collection service or recycler, the dental office must obtain written or electronic certification documenting: the name and address of the collection service; the amount, by weight, of dental amalgam waste collected and the date it was collected; the name and address of the facility where the dental amalgam waste will ultimately be recycled; and certification that the mercury contained in the waste was destined for recycling. The dental facility should keep this information on an annual basis for a period of three years.

The intent of the record keeping requirement is to require the dentist to maintain records from the recycler of the amount of dental amalgam waste generated by the dental office and sent for recycling. This waste will inevitably contain various materials such as scrap amalgam and used amalgam capsules to polishing paste, body tissues, wastewater, amalgam particles, and tooth fragments retained by chair-side traps, filters, and amalgam separators. There is no requirement for the dentist to identify or measure the amount of mercury sent for recycling. The actual amount of mercury in dental amalgam waste is unknown when the waste is sent for recycling.

Dentists must enact these mercury managing requirements at their facilities. Mercury is considered a hazardous waste and must be properly managed. It is not legal for dental offices to dispose of mercury or mercury amalgam waste in the regular trash, down a drain, or through incineration. It is also not appropriate to dispose of any mercury capsule or amalgam waste with medical waste. Most medical waste is incinerated or autoclaved which causes mercury to volatilize and enter the atmosphere.

5. What is an amalgam separator and what is the purpose of this equipment?

An amalgam separator is equipment placed in-line and designed to capture dental amalgam particles from a dental facility's wastewater. This reduces the amount of amalgam particles entering the sewage system. The equipment accomplishes separation of the amalgam particles by centrifuge, filtration, sedimentation, ion exchange or any combination of these methods.

Chair-side traps, combined with vacuum filters, remove some of the amalgam waste; however, the percentage of amalgam waste removed increases to 99% with the installation of an amalgam separator. An amalgam separator, certified to International Organization for Standardization (ISO 11143), is a reasonable and cost effective means for the dental community to help protect the environment from mercury contamination.

There are a number of manufacturers that produce amalgam separators. Multiple models are available and should be closely reviewed to determine which amalgam separator will work best in your dental facility. Suppliers usually install these systems, and maintenance agreements are common.

6. Are chair-side traps and vacuum filters enough to capture dental amalgam?

These traps and filters do capture a portion of the amalgam waste, which is usually "coarse" dental amalgam; however, various studies suggest approximately 40% - 60% of the dental amalgam waste passes through these traps and filters. Amalgam separators ensure the capture of "fine" materials and waste that passed through the traps and filters. In addition, some dental facilities are switching from wet vacuum pump systems to dry vacuum pump systems. Dry vacuum pump systems do not require a vacuum filter.

7. Which dental facilities must install an amalgam separator?

All dental facilities must install an amalgam separator(s)where dental amalgam is applied, altered, maintained, removed, or disposed; where dental amalgam waste is generated; or where elemental mercury is used or possessed by licensed dentists.

Dental facilities not required to install an amalgam separator are specialties where orthodontics, periodontics, prosthodontics and oral and maxillofacial surgery are exclusively performed. Exemptions are not granted to other dental facilities.

Although the exempted specialties listed above are not required to install an amalgam separator, they must properly collect, store, and recycle dental amalgam waste. For instance, extracted teeth containing dental amalgam, chair-side traps, and vacuum pump filters must be sent to a mercury waste recycler.

8. By what date must the dental facilities have an amalgam separator installed?

Dental facilities operating prior to May 12, 2006 have two years (until May 12, 2008) to install an amalgam separator. If a dental facility begins operations after May 12, 2006, an amalgam separator must be in place prior to the beginning of the facility's operation.

9. What standards must the amalgam separator meet?

It is important for a dentist to confirm that the amalgam separator meets the ISO 11143 Standard. The Standard is designed to ensure that the equipment removes nearly all dental amalgam from the wastewater discharged through the equipment.

The amalgam separator must be installed, operated, and maintained in strict accordance with the manufacturer's specifications and recommendations. Applicable state and local building code requirements must be followed when an amalgam separator is installed, and the separator must be properly sized for the volume and flow of the dental facility's amalgam wastewater. Typically, a dental facility will produce the most flow when line cleaning is performed at the end of the day. The line cleaning process disinfects the line and also pushes residual amalgam through the line creating the need for a separator to efficiently perform at a higher flow rate. The maximum flow rate capacity, which the separator tested at and met to pass the ISO Standard, must not be exceeded.

The performance requirement (95% or 99%) for the amalgam separator is determined by the date it is placed into service. An amalgam separator in service at dental facilities prior to May 12, 2006 must be ISO 11143 certified and achieve a minimum 95% removal efficiency of dental amalgam. An amalgam separator placed into service after May 12, 2006 must be ISO 11143 certified and achieve 99% removal efficiency.

Large dental facilities (50 or more chairs) must also adhere to either of the above performance standards according to the date that the amalgam separator is placed into service. Because the ISO Standard is not written for large separators, a large separator cannot be certified under the Standard. The appropriate removal efficiency certification must be made by a person or firm licensed to practice professional engineering in the State of New York.

A large dental facility may install multiple amalgam separators of the same model that are capable of processing the facility's large flow rate. Specific separator models do exist that are designed to address the demands of institutional settings and have been appropriately tested and certified by accredited testing laboratories and certification bodies.

10. What is 99% efficiency?

An amalgam separator will collect dental amalgam waste which consists of a myriad of waste materials such as polishing paste, tissue, tooth fragments, and amalgam particles to name a few. The efficiency of an amalgam separator is determined by measuring the mass percentage of the amalgam retained by the separator. A separator with 99% efficiency means 99% of the dental amalgam is retained by the separator and 1% is passed through the separator with the wastewater. The material, retained in the separator, must be sent for recycling. Water, which is treated by and passes through the amalgam separator, is no longer considered dental amalgam waste.

11. Is flow rate important for an amalgam separator?

According to law, the flow rate entering the amalgam separator should not exceed the tested flow rate (the flow rate the separator was tested at using the ISO 11143 test procedure and achieving 99% efficiency)during all maintenance or operational procedures performed at the dental office. Dental offices generate different flow rates during both procedures. For instance, a liter or more of line disinfectant may be flushed through the system during routine maintenance procedures. Dental facilities may also perform multiple line cleaner flushings throughout the day or multiple operatories may be flushed with line cleaner at the same time. Line cleaning creates "peak flow" conditions that pushes residual materials through the line. The appropriately sized separator is very important to capture dental amalgam and to prevent untreated wastewater from passing through the system when excessive flow is encountered. Some amalgam separators offer flow restrictors to assure the appropriate flow rate is maintained.

Although operational procedures may not create "peak flow" conditions, dental facilities may perform various procedures by multiple staff at the same time thus creating a substantial flow. Cuspidor use also increases the flow. Every dental facility performs both maintenance and operational procedures so it is very important to consider separators that can accommodate the flow rate generated by your dental facility. A separator vendor can provide information concerning properly sized models that have adequate tanks and flow restrictors appropriate for your office.

12. What factors should a dental facility consider when purchasing an amalgam separator?

There are many aspects to consider when installing a separator such as peak flow rate and number of operatories, existing wet or dry vacuum system, existing cuspidors, space limitations, maintenance requirements, warranties, post installation service, and cost (including purchase price, installation fees, replacement parts/tanks, and labor). Flow restrictors should also be considered to make sure the separator is operating at its appropriate flow rate. It is wise to request manuals so you can compare separator features and manufacturer recommendations.

After installation, the technician should test the vacuum system performance under typical conditions (chairs in use) as well as closed conditions (no evacuators in use) to make sure that the vacuum suction has not been compromised.

13. What are the costs involved with purchasing an amalgam separator?

Purchasing an amalgam separator can cost from a few hundred to several thousand dollars depending on the number of dental stations in your dental office and the separator that you select. Lease arrangements are possible and most manufacturers offer maintenance agreements for service, repairs and management of the waste mercury collected.

14. Must hygienist operatories and all cuspidors be treated by an amalgam separator?

Wastes generated from dedicated hygienist operatories and hygienist cuspidors do not need to be treated by an amalgam separator; however, most dental facilities have hygienist operatories and hygienists cuspidors connected to the same vacuum and drain lines as operatories that remove and replace dental amalgam. Wastes generated from hygienist operatories and hygienist cuspidors that are on the same drain and vacuum lines with an operatory that removes and replaces dental amalgam must be treated by an amalgam separator. In addition, any cuspidor that is on the same vacuum or drain line with an operatory that removes or replaces dental amalgam must have its wastewater treated prior to discharge by an amalgam separator.

Common activities, such as rinsing chair-side traps, screens, vacuum pump filters or other amalgam collection devices, generate mercury waste and should never be done over drains or sinks that are not connected to an amalgam separator. All dental facility waters that come in contact with dental amalgam waste must be treated by an amalgam separator prior to discharge.

15. What documentation does the NYS Department of Environmental Conservation (Department) require from separator manufacturers and distributors to verify that an amalgam separator has been tested and certified according to ISO 11143 Standards?

According to regulation, the Department requires that amalgam separators sold to NYS dental facilities are certified and tested according to the ISO 11143 Standard. This means that separators should be tested and certified by accredited testing laboratories and certification bodies. The Department is requiring that separator manufacturers provide current and valid certificates and test reports which demonstrate 99% efficiency.

A list of separator manufacturers and distributors that have provided appropriate certificates and test reports to the Department may be obtained from the Department's website.

16. Who must be notified when a separator is installed?

When a separator is installed at a dental facility, the dental facility provides written notification to the appropriate sewage treatment works or sewer authority where the wastewater is discharged. For dental facilities that begin operations after May 12, 2006, notification must be submitted within 30 days from the date the separator is placed into service. For dental facilities operating prior to May 12, 2006, notification must be submitted no later than June 12, 2008. Dental facilities that are on septic systems should complete a form and keep it in their records.

The notification must include the dental facility name, address, telephone number, type of amalgam separator installed, manufacturer's model number, unit specifications (e.g. ISO 11143 tested flow rate, efficiency), date the unit was placed into service, and the number of chairs serviced by the separator. A copy of Notice of Dental Mercury Separator Installation form (PDF, 35 KB) may be obtained from the Department's website.

17. How long must a dental facility keep the amalgam separator's records on file?

A dental facility keeps the following information on file for as long as the separator is in use at the dental facility: type of amalgam separator installed, manufacturer's model number, unit specifications, date the unit was placed in service, and the number of chairs serviced by the separator.

For a minimum of three years, the dental facility keeps a description and a date of all maintenance performed on a separator. These records and any related equipment records must be available for inspection by the Department or its authorized representative upon written or verbal request.

All dental facilities, including specialties that are exempt from installing a separator, must maintain the following written documentation from the collection service or recycler for a minimum of three years: the name and address of the collection service; the amount, by weight, of dental amalgam waste and elemental mercury collected and the date it was collected; the name and address of the facility where the dental amalgam waste and elemental mercury will ultimately be recycled; and certification that the mercury contained in the waste was destined for recycling.

18. A dental facility must not store dental amalgam waste for more than one year from the date the waste was initially placed in the container. Does this one-year storage rule also apply to dental amalgam waste retained in the separator?

The Department views an amalgam separator as a piece of equipment not a collection container. A canister/cartridge that is not removed from the separator equipment system is considered a part of the system and does not fall under the one year storage limitation requirement.

If a dental facility chooses to reuse the canister/cartridge and empties the dental amalgam waste sludge from the canister/cartridge into a collection container, the waste sludge must not be stored at the dental facility for more than one year from the date the sludge was placed in the collection container. If the dental facility replaces a used canister with a new canister, the used canister is no longer considered part of the separator equipment system and is subject to the one year storage limitation requirement.

The one year storage provision also applies to dental amalgam waste, such as but not limited to, extracted teeth with dental amalgam restorations, carving scrap, vacuum pump filters and chair-side traps taken out of service, excess dental amalgam mix, and used dental amalgam capsules. Question 4 provides more storage information on contact and non-contact dental amalgam waste.

19. Some separator manufacturers have recommended "snaking" the lines prior to separator installation. Is this appropriate?

No. This procedure may release a high level of residual dental amalgam which contains mercury and has accumulated in the lines over a period of time. It is far better to install the separator prior to snaking the lines.

20. Will the installation of a separator save me from changing the vacuum pump filter?

The separator captures more amalgam than the vacuum filter. Ideally, the separator should be placed before the vacuum filter to collect the majority of dental amalgam waste. Dental offices with a wet pump vacuum system should not need to change the vacuum filter as frequently if the separator is installed before the vacuum filter. A vacuum filter may need to be changed more often if the separator is placed after the vacuum filter. Also, the warranty for the vacuum system may become void if the separator is not installed correctly. The clinic may want to keep the vacuum filter in place to protect the vacuum pump.

Dental office staff can readily determine if a separator is performing efficiently by noting the amount of dental amalgam waste in the vacuum filter. If the separator is placed before the vacuum filter but a large amount of dental amalgam waste collects in the vacuum filter, a problem with the separator's ability to collect the waste may exist and vacuum may be compromised.

21. What pH level of line cleaner should I use in my system?

An appropriate line cleaner to clean suction lines is also recommended for sanitizing and deodorizing most separators. Separator manufacturers usually inform the dental facility of the appropriate line cleaner to use with the separator. Chlorine-based line cleaners, highly caustic (pH higher than 10) or acidic cleaners (pH lower than 4) can damage a separator and reduce removal efficiency by dissolving amalgam particles which can then pass through the separator. Chlorine bleach must never be used to sanitize and disinfect lines because it mobilizes mercury from amalgam.

22. How will this regulation be enforced?

The Department will perform random site inspections at dental facilities. During the inspection, Department staff will verify separator installation and recycling of dental amalgam waste. Dental facility records which may be reviewed by Department staff include separator installation and maintenance records; the amount, by weight, of dental amalgam waste (may be both contact and non-contact amalgam, filters, traps, etc.) sent for recycling on an annual basis; and certification from a collection service or recycler documenting its name/address, date/weight of dental amalgam waste and elemental mercury collected, and the name/address of the facility where the dental amalgam waste and elemental mercury will be recycled.

23. Where else can mercury and mercury wastes be found in a dental office?

Besides dental amalgam, mercury is present in some medical equipment such as thermometers and blood pressure reading devices. Certain thermostats contain mercury switches. Dental offices often use fluorescent and high-intensity lamps that contain mercury. There are non-mercury alternatives available for most of these items that a dentist should utilize when starting an office or replacing items. There are also lamps available that contain lower amounts of mercury than others.