Dispelling the Myths About Bleach Odors

By Krishna Reddy, PhD, DABT

Sodium hypochlorite, or common bleach, is one of the most widely available disinfectants on the market today, and is seeing a resurgence in popularity within healthcare settings, with the advent of harder-to-kill pathogens such as C. difficile spores and methicillin-resistant Staphylococcus aureus (MRSA). Some facilities are reluctant to use bleach-based disinfectants because of a misperception that bleach can cause respiratory issues in patients and staff. In the interest of informed decisions, we have gathered some information to help dispel this and other myths about bleach. This way, the next time you are evaluating disinfecting products for your facility, you can be appropriately informed.

Current uses of bleach (containing sodium hypochlorite at the concentration levels in most bleach-based disinfecting products) and bleach based disinfectants in healthcare settings, following the guidelines of use recommended by CDC, have an established history of effectiveness. The Environmental Protection Agency (EPA) has registered bleach for use in a variety of healthcare settings, from patient rooms and neonatal nurseries to respiratory therapy rooms when used as directed.

The real bleach: sodium hypochlorite bleach has been used since 1913 for disinfecting needs everywhere from hospitals and nursing homes to daycares and households. Most concerns about bleach actually stem from a misperception that bleach contains free standing chlorine. In fact the term chlorine bleach is a misnomer because sodium hypochlorite bleach (common bleach) has a unique chemistry that is derived from sodium chloride -- common table salt.

Furthermore, use of bleach as a disinfectant does not form dioxins. In its manufacturing process, hypochlorite bleach begins as salt and water. After use, the compound breaks down mainly into salt and water during or quickly after use. As an EPA-registered disinfectant, bleach classification as a "pesticide" and related language can sometimes cause further misperception when bleach is actually one of the worlds most widely available and used disinfectants.

Bleach and respiratory effects: The characteristic smell of bleach is indicative of a disinfected environment, but should not be a cause for concern for any adverse health effects. This is because the sensory threshold levels for chlorine species is well below any levels recognized to cause potential respiratory irritation, or overt health effects, and is reflected in the current occupational limits. It is unlikely that typical recommended uses of these disinfectants, used in accordance with the label directions, will exceed the occupational exposure limits for chlorine. In fact, the odor threshold for chlorine (when the scent is noticeable) is listed at 0.002 ppm in air and 0.31 ppm in water (EPA 1994b, 1999). Perceivable sensory irritation, however, occurs at 1.0 ppm in air, 500 times that of the odor threshold (EPA 1999. Cited from Toxicology Profile for Chlorine, ASTDR, USDHHS, September 2007). Odor complaints for bleach are not unlike complaints received for any other chemical with a noticeable smell. Investigation by Paustenbauch and Gaffney (Intl. Occup Env. Health. 79: 339-342, 2006) found that for some odorous chemicals, even when one maintains airborne concentrations below a particular OEL (Occupational Exposure Limit), this level of exposure may not be adequate to prevent all persons from reporting an appreciable adverse response. In some cases, workers pre-existing belief system about the source of an odor may be sufficient to create anxiety when exposed to any detectable concentration. This is why proper education is key: dispelling the fear of bleach odor through real facts and information can drastically reduce concerns and complaints.

Ways to minimize the odor: It is important to recognize that the distinct chlorine odor is an integral part of the usage of bleach disinfectants. The odor that is noticeable is actually caused by the chemical reaction that occurs when bleach begins to break down proteins, such as those that make up HAI-causing pathogens. The more frequently that surfaces are disinfected with bleach, the fewer proteins will be on the surface for the next disinfection. Essentially, the more frequent the surface is disinfected, the lower the odor should be.

End users of bleach products should be made aware that the exposure to the smell of bleach should not be a cause for concern. Even still, areas in which these disinfectants are being used should be kept well ventilated to ensure that the odors do not build up. In cases where bleach smell seems to linger or is particularly strong after cleaning has taken place, check to ensure the area is well ventilated and the product is not being overused.

If using a bleach-based spray, consider choosing a foam option instead of a spray on the trigger nozzle, if such an option exists. The foam has a narrower trajectory and is designed to cause the bleach to cling onto the surface instead of misting in the air. Note: As is standard industry practice (and required by Occupational Safety and Health Administration best practices interpretations), always follow the product label instructions and always refer to MSDS and the appropriate instructions.

Why use bleach for disinfecting: A combination of education and usage experience over time can help dispel fears about bleach usage. Let's face it, with hospital-acquired infections leading to 90,000 deaths and $4.5 billion in excess health care costs each year*and increasing regulations by states to make HAI statistics publicly availablebleach can be an effective tool to improve patient experience. It is an effective disinfectant that is recognized by the CDC and other agencies for killing C. diff spores, MRSA, Mycobacterium bovis (TB) and many other hospital-acquired pathogens. Its smell of clean can be a powerful, recognizable, and reassuring cue for patients and staff that they are in a clean and disinfected environment.

* CDC estimates: http://www.cdc.gov/media/pressrel/r060504.htm?s_cid=mediarel_r060504_x

Krishna Reddy, PhD, DABT, is a research fellow in product safety and global stewardship for The Clorox Company.