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For General Healthcare Settings in West Africa: Rationale and Considerations for Chlorine Use in Infection Control

Page Summary

Who this is for: Healthcare providers working in healthcare settings in West Africa.

What this is for: This guidance aims to address disinfection and antisepsis practices in West Africa, where chlorine solutions are primarily used but are not standardized and can vary widely in concentration and source.

How to use: This guidance is intended to help healthcare workers in cleaning and disinfection by preparing and using chlorine solutions.

Key Points

  • Cleaning and disinfection are important ways to help stop the spread of Ebola virus.
  • Chlorine solutions, when prepared and used appropriately, can damage Ebola virus.


Environmental cleaning is only one of several recommended methods to reduce transmission of deadly germs among patients and healthcare workers. Cleaning and disinfection, along with other infection control measures like hand hygiene and isolation precautions, are important ways to help stop the spread of Ebola virus 1-8. Both the World Health Organization10 and CDC have issued guidance on infection control measures specifically for African settings3, 4, 6, 9. Unlike in West Africa, U.S. recommendations for cleaning and disinfection of domestic-based healthcare facilities are standardized; U.S. Environmental Protection Agency (EPA)-registered hospital grade disinfectants, including chlorine-based products that claim effectiveness against nonenveloped viruses9, are recommended. Instructions for use of these products are usually provided on the label. While such products are suitable for use globally, they may not be readily available in West Africa. This guidance primarily aims to address disinfection and antisepsis practices in West Africa, where chlorine solutions are primarily used but are not standardized and can vary widely in concentration and source.

Description of Chlorine Use as a Disinfectant

Rationale for use

Chlorine solutions (Cl2, NaOCL, Ca[OCl]2, ClO) have been used extensively as disinfectants and antiseptics since the 1800s11. Guidance documents on use of these compounds for environmental and healthcare infection control in the context of the Ebola preparedness and response in the United States have recently been published9. Chlorine solutions are oxidative chemicals and have broad-spectrum activity against a wide variety of microorganisms, from viruses to protozoa11-31.

During Ebola responses, chlorine solutions of 0.5% (in the United States, this would generally be equivalent to a 1:10 dilution of household bleach) have been used for environmental surface disinfection, while a 0.05% solution has been used for hand hygiene. Nongovernmental organizations (NGOs) have typically provided hospitals and safe water programs with sodium dichloroisocyanurate (NaDCC), an EPA-approved pool chemical in the United States, for use in preparing disinfectant solutions as well as other chlorine-based products for disinfection use. There have also been some projects in Africa that have involved creating sodium hypochlorite electrolytically from brine solutions (primarily to disinfect drinking water, for example, CDC Safe Water, UNICEF Safe Water).

Bleach (sodium hypochlorite) solutions are produced in different concentrations in different parts of the world, and solution strength can vary between 2% and 12% NaOCl. (In comparison, most U.S. bleach products are currently 6%-6.15%, but can range from 2.5%-8.25%, depending on their intended use). Since there is such a wide variation in the strength of products available in West Africa, it is strongly recommend that concentration of the chlorine product be evaluated prior to use.

Validation of chlorine products

Concerns have been raised that certain locally produced chlorine hypochlorite products in West Africa have inferior quality or lack consistency, due either to poor manufacturing standards or human error during preparation. When in doubt about a product, it is recommended that the chlorine concentration be determined using chemical analysis (for example, DPD [N,N-diethyl-p-phenylenediamine] color-change test kits, amperometric titration for chlorine residuals, commercially available test strips, or dip sticks). Reagent-grade water will also be needed to make 1:100 and 1:1000 dilutions of the prepared solution in order to conduct the testing.

Considerations for Chlorine Use

  • There are no published or manufacturer-based studies that have tested the effectiveness of chlorine products against Ebola virus. However, chlorine solutions are known to be effective against a broad range of viruses11-31.
  • Wet contact time is the amount of time that a surface being disinfected should remain wet with disinfectant. Wet contact times for chlorine range from 2 minutes to 10 minutes depending on the microbe/virus. For wet contact times more than 10 minutes, chlorine solution or other acceptable disinfectant may have to be reapplied. When treating surfaces that are potentially contaminated with Ebola virus and other bloodborne pathogens, allow a wet contact time of 10 minutes with a chlorine solution of 0.5% to 0.6%.
  • Chlorine solutions and other disinfectants are inactivated by the presence of organic matter (blood, other proteinaceous material, dirt), heavy metal ions, low temperature, or ultraviolet irradiation. Both WHO and CDC recommend cleaning with detergent and water before applying disinfectant. This will help prevent inactivation of the disinfectant by organic matter8, 17, 32-34.
  • Chlorine solutions should not be used for routine hand hygiene, as they will eventually damage the skin. Soap and water or alcohol-based hand rubs are preferred (see WHO Guideline on Hand Hygiene in Health Care, 2009[PDF - 270 pages] and the Healthcare Infection Control Practices Advisory Committee’s Hand Hygiene in Healthcare Settings, 2002). Alcohol-based hand rubs (ABHR) offer benefits when compared with using soap and water in skin tolerance, compliance, and, especially when combined with glove use, overall effectiveness for a wide variety of healthcare pathogens. However, if hands become visibly soiled, use soap and water, not alcohol-based hand rubs3, 4.
  • Strong or mild chlorine solutions can be prepared from a number of different types of available products. To be effective, a solution with concentration that contains either 0.5%-0.6% (5000-6000 ppm) or 0.05-0.06% (500-600 ppm) of available chlorine, depending on its intended use, is required for infection control. Household bleach, which in the United States would be considered NaOCl (Pure bright, Clorox bleach, Clorox germicidal bleach, Ultra Clorox germicidal bleach, CCCP), is different from either Ca(OCl)2 (for example, HTH, chlorinated lime) or the locally prepared “bleach” products that are commonly found in West Africa. Understanding which product is being used to make a solution is very important, as the amount of dilution needed for a product to be effective will vary.
  • Other considerations:
    • Chlorine solutions should be prepared fresh daily, as they are light sensitive.
    • Most chlorine products require the removal of organic soil prior to their use (removing bulk spill matter, cleaning prior to disinfecting).
    • Disinfection requires a wet contact time (amount of time the disinfectant is required to be left on the surface to be effective).
    • Chlorine odor does not necessarily indicate appropriate solution strength, since chlorine odor can be detected even at extremely low concentrations.
    • Chlorine solutions are corrosive and can pit metal and damage skin.

Preparing Bleach Solutions for Infection Control

  • When preparing chlorine-based solutions, remember that there is no one simple dilution that can be used to arrive at the working concentration. How much dilution is needed depends on what type of product is available in West Africa. The following guidance can be used in the preparation of chlorine solutions. Be sure to wear appropriate personal protective equipment (PPE) to avoid chlorine toxicity (chemical resistant gloves, dust/mist respirator, and face shield or goggles)35.
    • Before use, consult the Material Safety Data Sheet (MSDS) [Word - 8 pages] for a full description on how to safely handle the product.
    • Make a 0.05% (approximately 500 ppm) chlorine solution by adding one tablespoon of HTH granules to 20 liters of clean water and stir for 10 seconds.
    • Make a 0.5% (5,250 ppm) hypochlorite solution by adding 10 heaping tablespoons of HTH granules to 20 liters of clean water. After mixing, wait 30 minutes to allow all of the Ca(OCl)2 granules to dissolve.
  • As an alternative, the following can be used to prepare chlorine solutions from either sodium hypochlorite (liquid) or calcium hypochlorite.
    • [% hypochlorite in liquid bleach as indicated on the label/% hypochlorite in the use solution] - 1 = total parts of water for each part of liquid bleach.
    • [% hypochlorite in use solution/% hypochlorite in the granules or powder as indicated on product label] x 1000 = amount in grams of granules to add to each liter of water.


  1. CDC. When Caring for  Patients Under Investigation or Patients with Confirmed Ebola Virus Disease (EVD).
  2. CDC. Infection Prevention and Control Recommendations for Hospitalized Patients Under Investigation (PUIs) for Ebola Virus Disease (EVD) in U.S. Hospitals.
  3. CDC. 2007 Guideline for Isolation Precautions: Preventing Transmission of Infectious Agents in Healthcare Settings.
  4. CDC. Guideline for Hand Hygiene in Healthcare Settings, 2002.
  5. WHO. WHO Guideline for Hand Hygiene in Healthcare, 2009.
  6. CDC. Infection control for viral hemorrhagic fevers in African healthcare settings, 1998 [PDF - 209 pages].
  7. Rutala WA, Weber DJ, Hospital Infection Control Practices Advisory Committee. Guideline for disinfection and sterilization in healthcare facilities, 2008 [PDF - 158 pages].
  8. Sehulster LM, Chinn RYW, Arduino MJ, Carpenter J, Donlan R, Ashford D, Besser R, Fields B, McNeil MM, Whitney C, Wong S, Juranek D, Cleveland J., Hospital Infection Control Practices Advisory Committee. Guidelines for environmental infection control in healthcare facilities, 2003, Recommendations from the CDC and the Healthcare Infection Control Practices Advisory Committee (HICPAC). Chicago, IL; American Society for Healthcare Engineering/American Hospital Association, 2004 [PDF - 249 pages].
  9. CDC. Interim Guidance for Environmental Infection Control in Hospitals for Ebola Virus.
  10. WHO. Interim Infection Prevention and Control Guidance for Care of Patients with Suspected or Confirmed Filovirus Haemorrhagic Fever in Health-Care Settings, with Focus on Ebola. WHO, Geneva, Switzerland, 2014.
  11. Rutala WA, Weber DJ. Uses of inorganic hypochlorite (bleach) in health-care facilities. Clin Microbiol Rev 1997;10(4):597-610.
  12. Bond WW, Favero MS, Petersen NJ, Ebert JW. Inactivation of hepatitis B virus by intermediate-to-high-level disinfectant chemicals. J Clin Microbiol 1983;18(3):535–538.
  13. Bond WW, Petersen NJ, Favero MS. Viral hepatitis B: aspects of environmental control. Health Lab Sci 1977 Oct;14(4):235-52.
  14. Bühler S, Roddy P, Nolte E, Borchert M. Clinical documentation and data transfer from Ebola and Marburg virus disease wards in outbreak settings: health care workers' experiences and preferences. Viruses 2014 19;6(2):927-37.
  15. Ching TY, Seto WH. Hospital use of chlorine disinfectants in a hepatitis B endemic area--a prevalence survey in twenty hospitals. J Hosp Infect 1989;14(1):39–4.
  16. Croughan WS, Behbehani AM. Comparative study of inactivation of herpes simplex virus types 1 and 2 by commonly used antiseptic agents. J Clin Microbiol 1988;26(2):213–215.
  17. Favero MS, Bond WW. Chemical disinfection of medical and surgical materials. In: Block SS, ed. Disinfection, sterilization, and preservation. Philadelphia: Lippincott Williams & Wilkins, 2001:881-917.
  18. Garcia EG, Del Peso G, Celadilla O, Castro MJ, Martinez V, Muñoz I, Sanchez-Villanueva R, de Guevara CL, Selgas R, Bajo MA. Efficacy of sodium hypochlorite in eradicating hepatitis C virus (HCV)-RNA from the peritoneal effluent of PD patients. Perit Dial Int 2010;30(6):644-6.
  19. Hulkower RL, Casanova LM, Rutala WA, Weber DJ, Sobsey MD. Inactivation of surrogate coronaviruses on hard surfaces by health care germicides. Am J Infect Control 2011;39(5):401-7.
  20. Kadurugamuwa JL, Shaheen E. Inactivation of human enterovirus 71 and coxsackie virus A16 and hand, foot, and mouth disease. Am J Infect Control 2011;39(9):788-9.
  21. Kahler AM, Cromeans TL, Roberts JM, Hill VR. Effects of source water quality on chlorine inactivation of adenovirus, coxsackievirus, echovirus, and murine norovirus. Appl Environ Microbiol 2010 Aug;76(15):5159-64.
  22. Koo D, Bouvier B, Wesley M, Courtright P, Reingold A. Epidemic keratoconjunctivitis in a university medical center ophthalmology clinic; need for re-evaluation of the design and disinfection of instruments. Infect Control Hosp Epidemiol 1989;10(12):547–552.
  23. Mbithi JN, Springthorpe VS, Sattar SA. Chemical disinfection of hepatitis A virus on environmental surfaces. Appl Environ Microbiol 1990;56(11):3601–3604.
  24. Park GW, Sobsey MD. Simultaneous comparison of murine norovirus, feline calicivirus, coliphage MS2, and GII.4 norovirus to evaluate the efficacy of sodium hypochlorite against human norovirus on a fecally soiled stainless steel surface. Foodborne Pathog Dis 2011;8(9):1005-10.
  25. Russell AD. Bacterial resistance to disinfectants: present knowledge and future problems. J Hosp Infect 1998;43:S57-68.
  26. Rutala WA, Cole EC, Thomann CA, Weber DJ. Stability and bactericidal activity of chlorine solutions. Infect Control Hosp Epidemiol 1998;19(5):323-7.
  27. Sattar SA, Jacobsen H, Springthorpe VS, Cusack TM, Rubino JR. Chemical disinfection to interrupt transfer of rhinovirus type 14 from environmental surfaces to hands. Appl Environ Microbiol 1993;59(5):1579-85.
  28. Sattar SA, Jacobsen H, Rahman H, Cusack TM, Rubino JR. Interruption of rotavirus spread through chemical disinfection. Infect Control Hosp Epidemiol 1994;15(12):751–756.
  29. Sattar SA, Springthorpe VS, Karim Y, Loro P. Chemical disinfection of non-porous inanimate surfaces experimentally contaminated with four human pathogenic viruses. Epidemiol Infect 1989;102(3):493-505.
  30. Van Bueren J, Simpson RA, Salman H, Farrelly HD, Cookson BD. Inactivation of HIV-1 by chemical disinfectants: sodium hypochlorite. Epidemiol Infect 1995;115(3):567-79.
  31. Ward RL, Bernstein DI, Knowlton DR, Sherwood JR, Young EC, Cusack TM, Rubino JR, Schiff GM. Prevention of surface-to-human transmission of rotaviruses by treatment with disinfectant spray. J Clin Microbiol 1991;29(9):1991–1996.
  32. Bloomfield SF, Miller EA. A comparison of hypochlorite and phenolic disinfectants for disinfection of clean and soiled surfaces and blood spillages. J Hosp Infect 1989;13(3):231-9.
  33. Weber DJ, Barbee SL, Sobsey MD, Rutala WA. The effect of blood on the antiviral activity of sodium hypochlorite, a phenolic, and a quaternary ammonium compound. Infect Control Hosp Epidemiol 1999;20(12):821-7.
  34. Weber DJ, Barbee SL, Sobsey MD, Rutala WA. The effect of blood on the antiviral activity of sodium hypochlorite, a phenolic, and a quaternary ammonium compound. Infect Control Hosp Epidemiol 1999;20(12):821-7.
  35. Arch Chemicals. Material Data Safety Sheet: HTH®, Calcium Hypochlorite [Word - 8 pages].