- Created on Wednesday, 02 January 2002 14:27
- Written by Staff
In his November letter to the editor, Dr. Nathan Belkin raises an issue of critical importance to public health: Is there adequate disinfection of linens and other textiles in health care facilities, especially with the growingconcern over transfer of bacterial infections among patients. The Design for the Environment (DfE) program shares Dr. Belkin's concern, but finds his advocacy of chlorine bleach as the sole solution to disinfection challenges in health care facility laundries a position that must be carefully examined--and perhaps seriously questioned.From its inception, the DfE formulator initiative has raised issues with the use of chlorine bleach in laundry detergent systems. Sodium hypochlorite (NaClO), the active ingredient in chlorine bleach, is a chemical with more than its share of potential risks and negative characteristics, among them:
Toxicity. Chlorine bleach is highly toxic, corrosive if swallowed or inhaled. It is the source of more poison exposures than any other substance--over 60,000 incidents reported to poison control centers in 1999 alone (according to statistics from the American Association of Poison Control Centers, Toxic Exposure Surveillance System, www.aapcc.org). Of note, these statistics also indicate that ocular, dermal, and inhalation exposures, while less frequent than ingestion cases, tend to be more serious.
Chlorine concentrations of 30 parts per million (ppm) cause immediate chest pain, vomiting, and coughing; at 430 ppm, death occurs in 30 minutes; and exposures of 1000 ppm cause death in minutes (see US EPA Air Toxics Website). In addition, it can combine with other wash room chemicals in hazardous ways: with certain substances, like ammonia or acids, it forms a toxic gas.
Generation of trihalomethanes (and other chlorination by products). In the presence of organic matter, found in abundance on health care laundry textiles, chlorine forms harmful byproducts, including trihalomethanes (THMs), the most common class of chlorination by products (chloroform is a THM). Overexposure to trihalomethanes may increase the following risks to human health: liver, kidney, and central nervous system damage, miscarriages, neural tube defects, and cancer (esp. of the bladder, colon, and rectum).
The U.S. EPA regulates trihalomethanes and soon will lower the allowable amounts in drinking water from 100 to 80 parts per billion (rule to take effect for large water systems in Jan. 2002). Humans receive their highest exposure to trihalomethanes through skin contact and inhalation, especially when water is heated. The health care laundry room, where chlorine bleach, heated chlorinated water, and heavily soiled linens mix and washing vapors are vented, certainly would seem to present the potential for elevated trihalomethane exposures.
Inefficient use of resources. A chlorine-based bleaching system is chemical and resource intensive. Chlorine bleach performs best at high wash temperatures and requires anti-chlor chemicals and an extra rinse step to neutralize the wash water and to arrest chlorine's fabric-damaging properties. The result: wasted energy, water, chemicals, linens and dollars.
Because of these concerns, DfE has recommended that laundry detergent formulators consider alternatives to bleaching with chlorine. DfE formulator partners have switched to oxygen bleaches and blends, like hydrogen peroxide or sodium percarbonate mixed with tetra acetyl ethylene diamine (TAED) (mixture forms peracetic acid in the wash water), with very successful results. The challenge for oxygen bleach alternatives has been to meet state and federal sanitizing and disinfection standards, and achieve an equal footing with chlorine bleach, the industry standard.
Problems with Chlorine Bleach as a Sanitizer. A question DfE believes should be raised, however, is whether chlorine bleach should remain the industry standard. While an able sanitizing agent in certain contexts, the purification of drinking water being the most familiar example, the health care facility laundry room may not be one of them. There appear to be significant issues on both the adequacy of chlorine bleach application in institutional laundries and the chemical's effectiveness in heavy soil conditions.
With respect to appropriate dosing, there seems to be a major disconnect between the manufacturer's specifications for sanitizing textiles and standard laundry practices. According to the Clorox company, sanitizing fabrics (like dishcloths) requires sodium hypochlorite concentrations of 2700 parts per million or 6 ounces NaClO (at a 6% solution) per gallon of water. Achieving that concentration in the wash aisle, for example, using a 50-pound washer with a fill level of about 22 gallons, would mean adding 1 gallon of chlorine bleach per load. That's over 50 times the normal bleaching level. (And if laundries were to bleach at sanitizing levels, consider the wear and tear on linens and additional replacement costs.)
Of even greater concern than insufficient bleaching is the possibility that chlorine bleach may be unable to adequately disinfect linens in the heavy soil conditions common at health care facility laundries, regardless of dose. According to summary laboratory data supplied to DfE by a formulator partner company, sodium hypochlorite fails to eliminate a number of common, disease-carrying microorganisms when applied in the presence of dirt or soil. Among the bacteria against which chlorine bleach may be ineffective in the institutional laundry are: staphylococcus aureus, echerichia coli 9 (E-coli), salmonella cholerasuis, pseudomonas aeruginosa, and proteus mirablis. Organic material appears to bind up the reactive chlorine molecule, significantly weakening its biocidal properties.
The challenges to safe and effective use of chlorine bleach in the institutional laundry room may be insurmountable. It takes large quantities of NaClO to disinfect under normal soil conditions; it's not clear how much more would be needed under heavy soil conditions or whether complete disinfection is even possible. And disinfection at what price to laundry room workers? More chlorine bleach means more potential poisonings and more THMs in the air, increasing long-term health risks.
Alternatives to Chlorine Bleach. Accelerated oxygen bleaches, like peracetic acid, may offer a solution. They can bleach and apparently sanitize very effectively. Based on information from a raw material supplier, peracetic acid is far more effective than chlorine bleach in killing bacteria under heavy soil conditions (when tested as hard surface cleaners, quaternary ammonium also yielded generally poor kill rates).
In the institutional laundry context, recent laboratory tests on hospital wash water, sponsored by a DfE formulator partner, indicate that, in the presence of high levels of organic matter (fecal material, blood, etc.), peracetic acid is an effective biocide and sodium hypochlorite is not. (Note: Peracetic acid works best to kill bacteria when combined with surfactants and certain enzymes that weaken bacteria cell walls.)
While pre-formed peracetic solutions are highly corrosive and flammable, generating this chemical at the point of use, for example in laundry wash water, eliminates these concerns. This form of peracetic acid also appears to generate far fewer THMs than chlorine bleach. (Note: Products sold as sanitizers must be registered with the U.S. EPA and a registration number should appear on the label.)
Based on this information, albeit preliminary, one must ask whether the high incidence of hospital patient infections may be linked to inadequate disinfection procedures and whether the current heavy reliance on chlorine bleach may be contributing to this problem.
Next Steps. In view of the potential serious shortcomings of sodium hypochlorite as a disinfectant of heavily soiled textiles and concerns over the chemical's health and environmental effects, the DfE program believes that its widespread acceptance and use in the health care sector demands a thorough re-evaluation. We hope Dr. Belkin agrees and will join us in advocating additional research and study, and in the meantime, a precautionary approach. Public health officials must determine the extent to which patients, wash room employees, hotel clients, and others may be at risk if current sanitizing practices prove inadequate. The effects on biocidal activity of wash water and dryer temperature, among other factors, must be carefully evaluated.
While the research continues, DfE asks laundry detergent formulators and users to consider their bleaching options. In a world full of risks, many beyond our control, laundry bleaching may offer an opportunity to act preventively. As DfE often reminds: If a chemical of concern is not in your formulation, you don't have to worry about it. By using a chlorine bleach substitute, one with a positive environmental profile that effectively meets your laundry needs, you will have taken a positive step toward making the planet a safer and more healthful place.
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