Managing Hazardous Waste: Amalgam

Nov. 1, 2006
All dental facilities deal with general and regulated waste. One type of regulated waste is hazardous waste.

All dental facilities deal with general and regulated waste. One type of regulated waste is hazardous waste. Once employees are trained in the procedures of handling, management and disposal, hazardous waste management is not complex. Dental hygienists need to be aware of the federal and state regulations associated with the different types of dental waste. A comprehensive program of infection control and safety includes policies, procedures and practices relevant to dental waste.

The goal of a waste management program is to provide all dental health-care workers (DHCW) with a working knowledge of potential health hazards and the regulatory standards associated with hazardous products. This includes being able to:

  • Review health hazards
  • Identify proper management and disposal techniques
  • Identify issues relevant to amalgam waste
  • Develop monitoring protocols for OSHA-regulated chemicals
  • Develop appropriate procedures for cleanup/spills
  • Be aware of resources available.
  • Identifying the waste and risks The first step in managing hazardous waste is to identify the type of waste. The dental hygienist may be the person designated to this task, and he/she should be sure a waste assessment has been done and is available for review. The primary types of hazardous wastes in dental settings are amalgam wastes and other office wastes. Amalgam wastes include contact amalgam, non-contact amalgam, unused amalgam, and elemental mercury. Other office wastes include silver-bearing X-ray fixer, cements, lead foil and lead shields, used chemicals, and disinfectants.Hazardous waste is regulated through the Occupational Safety & Health Administration (OSHA), Environmental Protection Agency (EPA), and state and local agencies. In 1987, OSHA extended the Hazard Communication Act (HAZCOM) to the health care industry. OSHA is the federal agency responsible for protecting the health and safety of workers. Under the HAZCOM standard, employers are obligated to inform employees of potential dangers associated with any chemicals they are exposed to during their duties; this applies only to chemicals “known to be present.” The idea behind the Standard is simple - employees have a right to know the hazards associated with the chemicals they work with and how to protect themselves through proper practices and personal protective equipment (PPE). Also, they must have access to Material Safety Data Sheets (MSDS) in the event of an exposure incident. The Standard applies to the handling, not disposal, of hazardous waste.Each dental facility must develop a HAZCOM plan for the office chemicals. This plan should discuss the physical and health risks of the chemicals, symptoms of exposure, how to detect the presence or release of hazardous chemicals in the work area, risk reduction techniques, follow-up for exposures, how to read labels and MSDS to obtain hazard information, and how to prepare an office-specific list of chemicals. Also included in the plan is employee training for the chemicals they use.For employee protection, every chemical container must be labeled with the identity of the agent and carry the appropriate hazard warning. This applies to all chemicals in the office inventory. The inventory should be kept up to date and the MSDS for each chemical should be available. Employees must be given appropriate PPE to use when handling waste. Offices must be properly ventilated to reduce exposure. It is prudent to limit hazardous chemicals and choose safer alternatives when possible. The National Institute of Occupational Safety & Health (NIOSH) has published a “Pocket Guide to Chemical Hazards” that provides information on common chemicals. It includes limitations, routes of exposure, PPE, respirator protection, and first aid. It’s a good idea to survey operatories to determine if all products are properly labeled according to the OSHA Standard.Amalgam waste Amalgam waste is regulated, and most states allow an exemption for mercury-containing dental amalgam generated by small quantity generators, provided the waste is recycled. It is in the best interest of an office to appropriately and through licensed facilities recycle all amalgam waste. Dental workers should avoid using bulk mercury, should never pour elemental mercury in the garbage, red bag or down the drain, and should never place amalgam of any kind in the biohazard bag, trash, or sharps container.Also, they should not rinse traps, filters or screens over the drain or into a wastebasket. If the office disinfects extracted teeth containing amalgam, employees should not use a heat treatment method. Other practices to avoid are pouring liquid used to store amalgam down the drain, rinsing tools used to place or carve amalgam over the drain, and cleaning elemental mercury spills with a vacuum cleaner. For proper use and maintenance of traps, read the manufacturer instructions.When you and other DHCWs handle amalgam waste, remember it may be mixed with saliva or blood and proper PPE should be used, including gloves, masks, and eyewear. All staff should be trained about the hazards of mercury. Carpeting should be avoided in areas where there is the potential for a mercury spill.Amalgam is not the sole hazardous waste of concern. Other dental materials of interest are silver-bearing X-ray fixer and films, zinc phosphate, zinc oxide, eugenol-based cements, lead foil and lead shields, and used chemicals. In addition, dental offices routinely use a wide variety of products that, once used, may become “universal wastes” under the EPA hazardous waste regulations. These include such items as thermometers, fluorescent bulbs, and button cell batteries. Universal waste regulations vary from state to state, so it is worth checking with your state environmental regulatory agency to see which items should be managed as universal wastes.Other sources of hazardous waste Finally, offices that are being renovated or closed can generate regulated hazardous wastes from dental chairs (hydraulic and lubricating oils), X-ray heads (cooling oils), lead shielding, and elemental and amalgamated mercury that can be found in carpets, piping, sink traps and other office locations. Dental offices that have been operating on septic systems should pay particular attention to collecting and proper disposal of office wastes.Here is a final word of caution. Remember that although you rely on your waste hauler to properly handle dental wastes, your office retains the ultimate responsibility and potential liability if dental wastes are not disposed of properly or are spilled or released en route to a disposal site. Ask your recycler about their insurance coverage and the regulatory status of the final recycling and disposal sites. A reputable recycler will readily provide this information.Proper management of dental office wastes will protect you and other DHCP from accidental exposures and reduce potential liabilities from OSHA and state agency inspections. A small investment in training and use of proper containers and procedures can be a big payoff for your office’s health and safety. OSAPKevin R. McManus, MA, MBA, is with EBI Consulting in Burlington, Mass. The company’s Web site can be visited at Bednarsh, RDH, MPH, is the Director of the HIV Dental Program at the Boston Public Health Commission. A life member of OSAP, she has lectured nationally and internationally on issues relevant to oral health, HIV, and on infection control.References 1 American Dental Association. Dental mercury hygiene recommendations. JADA, 1999; 130;11262American Dental Association. Best Management Practices for amalgam waste. Chicago, American Dental Association, 2003.3 American Dental Association. Managing Lead and Silver Waste in Dental Offices. JADA, 2003; 134; 1095-10964 U.S. Environmental Protection Agency. Hazardous Waste Regulations. 40 CFR Part 261 (can be accessed at U.S. Environmental Protection Agency. Little Known But Allowable Ways to Deal with Hazardous Waste U.S. Environmental Protection Agency Small Business Division Washington, D.C. May 20006 U.S. Occupational Safety and Health Administration. Hazard Communication Standard. 29 CFR 1910.1200. (Can be accessed at U.S. Occupational Safety and Health Administration. Bloodborne Pathogens Standard. 29 CFR 1910.1030. (Can be accessed at Useful Links • ADA links on Amalgam and Lead:
    • Minnesota Dental Society Publications:
    •Oregon Dental Association BMPs:
    • NY State Department of Conservation Recyclers List
    Exposure to amalgam waste You may or may not directly handle amalgam products, but there is a possibility that you could be exposed to its waste. The American Dental Association recommends Best Management Practices for dentists. These include:
  • Use of precapsulated alloys
  • Recycling used capsules
  • Salvaging, storing and recycling non-contact amalgam
  • Salvaging and recycling contact amalgam pieces from restorations after removal
  • Recycling extracted teeth with amalgam restorations (after disinfection)
  • Using disposable chair side traps to retain amalgam for recycling
  • Cleaning and replacing screens, traps, and filters on a routine basis
  • Storing amalgam waste in separate, airtight, labeled containers
  • Recycling all amalgam waste through an appropriate amalgam recycler (including used capsules)
  • Training all staff in spill clean-up procedures.