Cleaning and Decontamination Guidance

Public Health and Disease Concerns Related to Coast Guard Operations
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combined with a detergent. They do not damage treated surfaces. Disinfection can be achieved

after 10 - 20 minutes of contact.

2. Sodium Hypochlorite. Sodium hypochlorite is thought to oxidize microbial enzymes and cell

wall components. A 1:10 dilution of 5.25 percent sodium hypochlorite in water yields a solution

which can provide an intermediate level of disinfection in 10 minutes. Since sodium

hypochlorite solution tends to be unstable, a fresh solution must be prepared daily. It possesses a

strong odor and can be harmful to eyes, skin, clothing, upholstery and metals (especially

aluminum).

B. Chemical Disinfectants Not Recommended.

1. Alcohol. Alcohol is bactericidal against vegetative forms of bacteria through the denaturation of

cellular proteins. A 70 - 90 percent solution (diluted with water) is more effective than a more

concentrated solution. The disadvantages of alcohol use are (a) rapid evaporation, (b) lack of

sporicidal or viricidal activity, and (c) rapid inactivation by organic material. Alcohol alone

shall not be used for disinfection.

2. Quaternary Ammonium Compounds. In the past, benzalkonium chlorides and other "quats"

have been used as disinfectants because they were thought to be safe, inexpensive and to have

low surface tension. Their biocidal activity results in a breakdown of the bacterial cell

membrane producing an altered cellular permeability. As a group, these compounds have

several serious deficiencies. Being positively charged, they are attracted not only to bacteria but

also to glass, cotton, and proteins. This decreases their biocidal activity. The negatively charged

ions of common cleaners, soaps, and other compounds will also neutralize "quats." Some

"quats" have been shown to support the growth of gram-negative organisms. They are

ineffective against most spore formers, the Hepatitis B virus and the Tubercle Bacillus.