Managing Specific Wastes - Sterilants & Disinfectants


In a dental office, it is essential to be able to control infectious organisms. Sterilants and disinfectants are important tools for meeting that need. But because they are necessarily toxic to living organisms, sterilants and disinfectants must be handled carefully, and their associated wastes must be managed properly, to avoid causing unintentional harm as they fulfill their intended function.

Depending on the potential risk for infection associated with their intended use, patient-care items (dental instruments, devices, and equipment) are categorized by the Centers for Disease Control as critical, semicritical, or noncritical:

  • Critical items are used to penetrate soft tissue or bone (e.g., surgical instruments, periodotal scalers, scapel blades, surgical dental burs). They have the greatest risk of transmitting infection and should be sterilized by heat.
  • Semicritical items touch mucous membranes or nonintact skin and have a lower risk of transmission; because the majority of semicritical items in dentistry are heat-tolerant, they also should be sterilized by using heat (e.g., dental mouth mirrow, amalgam condenser, reusable dental impression trays, dental handpieces). If a semicritical item is heat-sensitive, it should, at a minimum, be processed with high-level disinfection.
  • Noncritical patient-care items pose the least risk of transmission of infection, contacting only intact skin, which can serve as an effective barrier to microorganisms (e.g., radiograph head/cone, blood pressure cuff, facebow, pulse oximeter). In the majority of cases, cleaning, or if visibly soiled, cleaning followed by disinfection with an EPA-registered hospital disinfectant is adequate. When the item is visibly contaminated with blood or OPIM, an EPA-registered hospital disinfectant with a tuberculocidal claim (i.e., intermediate-level disinfectant) should be used. Cleaning or disinfection of certain noncritical patient-care items can be difficult or damage the surfaces; therefore, use of disposable barrier protection of these surfaces might be a preferred alternative.

FDA-cleared sterilant/high-level disinfectants and EPA-registered disinfectants must have clear label claims for intended use, and manufacturer instructions for use must be followed. A more complete description of the regulatory framework in the by which liquid chemical germicides are evaluated and regulated is provided by CDC (see Regulatory Framework for Disinfectants and Sterilants).

Three levels of disinfection, high, intermediate, and low, are used for patient-care devices that do not require sterility and two levels, intermediate and low, for environmental surfaces. The intended use of the patient-care item should determine the recommended level of disinfection. Dental practices should follow the product manufacturer's directions regarding concentrations and exposure time for disinfectant activity relative to the surface to be disinfected. CDC has prepared a summary of sterilization and disinfection methods (see Methods for Sterilizing and Disinfecting Patient-Care Items and Environmental Surfaces).

Some common chemical sterilants and disinfectants used in dental offices include glutaraldehyde, glutaraldehyde with phenol, hydrogen peroxide, hydrogen peroxide with peracetic acid, ortho-phthalalhyde (OPA), alcohols (ethyl, isopropyl), quatemary ammonium chloride, oxidizers (bleach), formaldehyde and phenolics.

Disposal of Sterilant and Disinfectant Wastes

Unused disinfectant concentrates may be considered hazardous wastes in some cases. If so, they need to be managed under a particular set of rules (RCRA). You should also to check to see if the end product being used (i.e. the product after dilution) also needs to be managed under RCRA.

Here are a few considerations:

  • If the sole active ingredient of a sterilant or disinfectant is a P or U-listed waste, the product itself must be managed as a hazardous waste.  (This information should be available on the Material Safety Data Sheet (MSDS) that your supplier can provide for the product.)
  • A sterilant or disinfectant might also have to be considered a characteristic hazardous waste due to:
    • corrosivity: It is important to check the pH level of the product. Many products have pHs higher than 11 or lower than 2. A sterilant or disinfectant product may be considered hazardous if it has a pH of less than 2 or greater than 12.5. This information can be determined form the MSDS under the "Physical Data" category.
    • toxicity
    • reactivity

See the Hazardous Waste Determination page for more background information on this topic.

Some solutions can be disposed of to the sanitary sewer if the local POTW permits it. You are strongly advised to check with your POTW to determine what wastewater discharges of sterilants and disinfectants are acceptable.

A note on the disposal of ortho-phthalaldehyde (OPA)-containing products: Due to its toxicity, California legislation deemed Cidex OPA a hazardous waste beginning January 1, 2001. However, this legislation exempts healthcare facilities from tiered permitting regulatory requirements when treating Cidex OPA with glycine on site to render it a non hazardous waste. Note also that if local publicly owned treatment works (POTWs) or sewer agencies have other prohibitions against sewerage of aldehydes, facilities must seek approval for this process as well.  (Source: Replacing Ethylene Oxide and Glutaraldehyde, USEPA)

See HERC section on Sterilants and Disinfectants in Healthcare Facilities for definitions, properties, risks, compliance requirements, disposal options, P2 alternatives and other information.

More Resources

See HERC section on Sterilants and Disinfectants in Healthcare Facilities for information on properties, risks, compliance requirements, disposal options, P2 alternatives and other information.

The Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) provides EPA with the authority to oversee the registration, distribution, sale and use of pesticides.  FIFRA applies to all types of pesticides, including antimicrobials, which includes sterilants, disinfectants and other cleaning compounds that are intended to control microorganisms on surfaces.  FIFRA requires users of products to follow the labeling directions on each product explicitly. (go to HERC's FIFRA page).

Fact sheets on EtO and glutaraldehyde are also available from OSHA. 

The EPA provides a list of antimicrobial agents registered as pesticides.

The California Department of Health Services provides a detailed fact sheet on EtO in the workplace.

P2RX Topic Hubs—P2 for Hospital Sterilizers: P2 Opportunities
This primer is intended as a quick guide to the essential P2 information on hospital sterilizers, as well as a compilation of pertinent on-line resources.

Best Practices for the Safe Use of Glutaraldehyde - extensive best practices recommendations from the federal Occupational Safety and Health Administration (OSHA)

Glutaraldehyde: Occupational Hazards in Hospitals -  provides useful information on adverse health effects of glutaraldehyde and on how you can be exposed to glutaraldehyde, and suggests control methods and work practices to prevent or reduce your exposure to glutaraldehyde.  The brochure was published by the National Institute for Occupational Safety and Health (NIOSH), a division of the Centers for Disease Control.

Guideline for the Use of High-Level Disinfectants and Sterilants for Reprocessing of Flexible Gastrointestinal Endoscopes - information provided by The Society of Gastroenterology Nurses and Associates, Inc. (SGNA).


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