Medical and Hazardous Wastes Don’t Mix

One common situation with medical facility waste is unintentional mixing of hazardous waste and medical waste.

Medical facilities needing disposal service can include those listed below.

  • Laboratories
  • Dentist’s offices
  • Doctor’s offices
  • Acupuncture offices
  • Veterinarians
  • Clinics

Medical waste and hazardous have to be kept separate and disposed of separately for safety, to manage environmental health risks to all of us from managing waste, and to be in compliance with environmental regulations.

Medical waste definitions are at the end of this post. Fair warning: read at your own risk!

Hazardous waste is identified and handled by what chemical activities generated it, what chemicals are in it, or what chemical properties it has.

There are dozens of ways that hazardous wastes are handled properly and sustainably under the regulations. Medical wastes are generally burned to destroy pathogens. Wastes that are burned can’t have certain materials in them because incineration equipment is specifically designed to prevent specific contaminants from going up the smoke stack, but not all contaminants. Hazardous waste is one of the items that need to be kept out of incinerators unless they are specifically designed for a specific waste.

One examples of a crossover between these materials is amalgam dental waste. This waste might be in the form of teeth with metal fillings removed, or from suction systems that remove materials from patients during dental procedures. Waste from suction systems may be watery, sludge, or a mixture of water, sludge, and solids.

Amalgam use is fading away with the increasing use of tooth filling materials like composite resins, but when dentists replace amalgam fillings or remove teeth with amalgam fillings, small amounts of amalgam waste are still generated.

Even if amalgam is not used at a dental facility, there are rules that may apply requiring the installation of an amalgam separator, and this will generate amalgam sludge and other materials. See this article for further information. The Washington State Department of Ecology also has information at this web page.

When amalgam was still used in fillings, there were more recycling options available. Now with low-level, infrequent generation of amalgam waste, it may be best to segregate and dispose of these small amounts.

Amalgam (metal fillings) contain silver and mercury, which are hazardous waste metals. These metals must be kept out of medical waste.

Some best management practices to consider in handling amalgam waste at a dental office include those listed below.

  • Get UN-rated shipping containers from WasteXpress to accumulate your amalgam waste in.
    • A one-gallon container is usually best for cost management.
    • Disposal is charged by the container size, not by how much is in it.
    • Get two or more containers so that you can start using an empty one when one fills up.
  • Keep all amalgam waste separate from your medical waste, or biohazardous waste.
  • When your container is about 80% full, add disinfectant to the container.
    • Make sure nothing is present that will react with household bleach, such as ammonia.
    • Make sure the waste can be mixed and get something to mix it with.
    • Estimate how much waste volume is in the container, for example 3 quarts or 96 ounces.
    • Add 10% by volume household bleach to the container, or 10 ounces in our example.
    • Stir the waste and make sure that the bleach is well distributed.
    • Close the container, label it, and make sure and indicate that bleach has been added.
    • Call WasteXpress for a disposal quote or pickup


Washington State Biomedical Waste Definition

Adapted from Revised Code of Washington (RCW) 70.95K.010.


Medical waste is known as “Biomedical waste” in the regulations. It includes the categories below:

  • Animal waste
    • Waste animal carcasses
    • Body parts
    • Bedding of animals with human pathogenic microorganisms infectious to humans.
  • Biosafety level 4 disease waste
    • Specific government definition
    • Related to highly communicable infectious diseases
    • Blood
    • Excretions
    • Exudates
  • Cultures and stocks infectious to humans
    • Specimen cultures
    • Cultures and stocks of etiologic agents
    • Wastes from production of biologicals and serums
    • Discarded live and attenuated vaccines
    • Laboratory waste
      • Culture dishes
      • Blood specimen tubes, and
      • Devices used to transfer, inoculate, and mix cultures
  • Human blood and blood products
    • Discarded waste human blood and blood components
    • Materials containing free-flowing blood and blood products
  • Pathological waste
    • Human waste from surgery, obstetrical procedures, and autopsy
    • Biopsy materials
    • Tissues
    • Anatomical parts
    • Not teeth, corpses, remains, and anatomical parts for interment or cremation
  • Sharps waste
    • Hypodermic needles
    • Syringes with needles attached
    • IV tubing with needles attached
    • Scalpel blades
    • Lancets removed from original package


American Dental Association Brochure: Best Management Practices for Amalgam Waste

This brochure has basic information but is focused on facilities that use amalgam for fillings.