How to Dispose of High Level Disinfectants Safely


For many healthcare workers, the act of dumping non-deactivated disinfectant solutions down the drain is a common practice, with many believing that used HLD solutions cease to pose a substantial risk after either their reuse date has passed or if they have failed an MEC test.

Unfortunately, this represents a major - and potentially hazardous - misconception.

The truth is that most HLD solutions - including OPA, glutaraldehyde, hydrogen peroxide, and peracetic acid - remain highly biocidal after either occurrence 1....and the danger that these solutions can pose to both the integrity of one's drainage systems and the environment is substantial.

What's the Risk?

There are various reasons as to why, exactly, the disposing of non-neutralized HLD solutions can be so hazardous. One reason has to do with the fact that pouring used disinfectants into a sink or hopper can break the surface tension, resulting in a rapid off-gassing of toxic vapor that can be destructive to the environment. Another potential hazard? Drainage system pipes are typically made of either polyvinyl chloride (PVC) or copper, both of which are materials that can corrode and deteriorate when directly confronted with the chemicals that compose most major high-level disinfectant solutions. 1 2

The damage that these solutions can pose both structurally and environmentally is so severe, in fact, that in some areas of the country, it is actually illegal to dispose of used disinfectant solutions into a Publicly Owned Treatment Works (POTW) without first neutralizing the solution. Yale Environmental & Safety has the following to say with regards to disposing of solutions: "In no case shall a substance with a pH less than 5.0 be discharged, unless the POTW is specifically designed to accommodate such a discharge (GNHWPCA requires a pH of 5.5 to 9.5, WHWPCF requires a pH of no less than 5.5 to state permit pH high limit)." 3 4

Clearly, it's important to neutralize an HLD solution before disposing of it. But knowing exactly how to accomplish this can oftentimes appear to pose an intimidating hurdle, with many healthcare workers lacking a full understanding of where - and what - to start with.

The truth, however, is that the act of neutralizing the used chemical before disposal doesn't have to be difficult...just so long as you have the right tools.

Achieving Safe Neutralization

There are a variety of HLD solutions that can be utilized to help disinfect transducers, each of which require varying degrees of care and oversight, depending on the situation. Thankfully, when it comes to safely disposing of these solutions, there are also an array of tools that can be safely utilized to achieve neutralization of the chemicals before disposal.

  • Ortho-phthalaldehyde (OPA) and Glutaraldehyde solutions:
    • What Are They: OPA and glutaraldehyde are the most widely used liquid high-level disinfectants for heat sensitive devices (including endoscopes and endocavity ultrasound probes). 5
    • What Are The Requirements for Disposal?: When properly disposing of OPA-based and Glutaraldehyde-based solutions, there are a variety of well-regarded recommendations that users can and should abide by:
      • OPA:
        • CDC:
          • "The OPA must be disposed in accordance with local and state regulations. If OPA disposal through the sanitary sewer system is restricted, glycine (25 grams/gallon) can be used to neutralize the OPA and make it safe for disposal." 6
        • Cidex OPA HLD IFU:
          • "Check state and local disposal regulations. Glycine (free base) may be used as a neutralizer for Cidex OPA Solution prior to disposal, if required. A minimum of 25 grams of glycine (free base) should be used to neutralize one gallon of CIDEX OPA Solution. The minimum recommended neutralization time is one hour. Discard residual solution into drain. Flush drain thoroughly with water." 7
      • Glutaraldehyde:
        • OSHA:
          • "Dispose of glutaraldehyde solutions in accordance with local, state, and Federal regulations. Check with your local Publicly Owned Treatment Works (POTW) to determine if glutaraldehyde solutions can be disposed of in the sanitary system. Some POTWs may prohibit the disposal of glutaraldehyde solutions in the sanitary system or may require neutralization prior to disposal. If there are no disposal restrictions, glutaraldehyde solutions may be disposed of, along with copious amounts of cold water, into a drain connected to the sanitary sewer system." 8
    • Tool To Neutralize: Glute-Out is a glycine-based powder neutralizer (57 grams/gallon) that effectively deactivates glutaraldehyde and OPA solutions in five minutes, meeting all California EPA Requirements (CIVCO internal testing results indicated that OPA was at 6 pH after neutralization using Glute-Out). To learn more about how Glute-Out can effectively transform the way you dispose of your solutions - and save you time and stress - click here.
  • Hydrogen Peroxide and Peracetic Acid solutions:
    • What Are They: Hydrogen peroxide and peracetic acid are two chemicals that are often utilized as a high-level disinfectants for ultrasound transducers, containing an average pH of 2.5 to 3.0. and 2.8, respectively. 9 10
    • What Are The Requirements for Disposal?: Per Yale's aforementioned guidelines with regards to pH levels, both hydrogen peroxide and peracetic acid are considered too powerful to be disposed of without having been first properly and thoroughly neutralized.

      In some states or municipalities, there may be regulatory requirements which mandate the waste effluent discharged from a facility be within a specific pH range, commonly pH 5-9. In some cases, it may be appropriate to neutralize used product solutions to meet effluent requirements for a facility.

    • Tool to Neutralize: Oxid-Out is a neutralizer agent designed specifically for hydrogen peroxide and peracetic acid-based solutions, providing an environmentally safe - and easy-to-use - way of neutralizing HLD solutions in one minute (CIVCO internal testing results indicated hydrogen peroxide range from 6-7 pH after neutralization using Oxid-Out). To learn more about how Oxid-Out can help you to safely and simply neutralize your solutions, click here.


  1. OSHA Solutions. Why Neutralize High Level Disinfectants.
  2. Rooter Plumbing. Everything You Ever Wanted to Know About Home Drain Pipes.,made%20of%20iron%20or%20steel
  3. Frequent Questions About Hazardous Waste Identification.
  4. Yale Environmental Health and Safety. Procedures and Requirements for the Discharge of Wastewater.
  5. Science Direct. Phthalaldehyde.
  6. Chemical Disinfectants - Guideline for Disinfection and Sterilization in Healthcare Facilities.
  8. Best Practices for the Safe Use of Glutaraldehyde in Health Care.
  9. Science Direct. Hydrogen Peroxide.
  10. gov. Peracetic Acid Processing.