Household bleach as a surface disinfectant

By Noel Brandon Kelsch, RDHAP

I recently received a question from a reader. It said, "Dear Noel, my doctor switched us to using diluted household bleach as a surface disinfectant to save money in our office. Is this safe, and is it effective?"

This is an issue that keeps coming up. The media has talked about the effectiveness of bleach as a disinfectant in homes, but this does not translate to the dental setting. This issue really highlights why it is so vital to stay up to date with the Centers for Disease Control (CDC) findings, and how different the home environment is compared to the medical environment.

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Other articles by Kelsch

• Infection control and the dental lathe
• Risks of Dentistry to Personal Health
• Clostridium Difficile and Dentistry

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The 1993 CDC Guidelines on Infection Control in the Dental Setting stated, "A fresh solution of sodium hypochlorite (household bleach) prepared daily is an inexpensive and effective intermediate-level germicide. Concentrations ranging from 500 to 800 ppm of chlorine (a 1:100 dilution of bleach and tap water or one quarter cup of bleach to one gallon of water) are effective on environmental surfaces that have been cleaned of visible contamination. Caution should be exercised since chlorine solutions are corrosive to metals, especially aluminum."

This information is no longer accurate.

The 2003 guidelines supersede the 1993 guidelines. They state that over-the-counter products cannot be used as disinfectants. Only Environmental Protection Agency-registered products can be used as disinfectants in the medical setting.

In 2003 the CDC expanded the list of agents acceptable for surface disinfection from the 1993 Guidelines. An EPA-registered low-level disinfectant with an HIV/HBV claim or an intermediate-level disinfectant (tuberculocidal claim) may be used on any clinical contact surface not visibly contaminated with blood. Intermediate-level disinfectants should be used when the surface is visibly contaminated with blood or other potentially infectious material (OPIM).

Although low-level agents may be used under certain circumstances, there is little if any cost differential between low- and intermediate-level products. More importantly, the intermediate-level chemicals can be used regardless of the presence or absence of blood. Conversely, a low-level disinfectant cannot be used on a surface with visible blood contamination, requiring the purchase of both the low-level and the intermediate-level products.

Another significant change in the 2003 Guidelines is that ONLY EPA-registered agents should be used to disinfect clinical contact surfaces. Because household bleach is not EPA-registered for this purpose, diluted bleach should NOT be used. Additionally, the use of liquid chemical sterilants/high-level disinfectants (such as glutaraldehyde and related chemicals) for disinfecting environmental surfaces is not recommended.

To assure patient safety, it is vital to stay up to date with CDC guidelines. Check the label of any product you want to use for surface disinfection. If it does not have an EPA registration number, you cannot use it.

NOEL BRANDON KELSCH, RDHAP, is a syndicated columnist, writer, speaker, and cartoonist. She serves on the editorial review committee for the Organization for Safety, Asepsis and Prevention newsletter and has received many national awards. Kelsch owns her dental hygiene practice that focuses on access to care for all and helps facilitate the Simi Valley Free Dental Clinic. She has devoted much of her 35 years in dentistry to educating people about the devastating effects of methamphetamines and drug use. She is a past president of the California Dental Hygienists' Association.