excessive   amounts   of   exposure   time   required, corrosiveness, skin sensitization, and odor. Phenolics Chlorine Dioxide-Based Solutions Chlorine   dioxide   is   an   effective   surface disinfectant or sterilant. These solutions may be used for  high-level  disinfection  of  semicritical  items  that are not subject to corrosion. It has a rapid action of 3 minutes for disinfection or 6 hours for sterilization. As with sodium hypochlorite (bleach), there are several disadvantages: chlorine dioxide must be discarded daily; has a 24-hour use life as a sterilant; and does not readily  penetrate  organic  debris. It must be used with protective eyewear and gloves because it is extremely irritating to the eyes and skin. It should always be placed in closed containers, and you must  ensure  adequate  ventilation  when  using  for surface disinfection. In addition, it corrodes aluminum containers. Iodophors Iodophors  are  classified  as  intermediate-level disinfectants or can be used as antiseptics if the product label claims tuberculocidal (lethal to mycobacterium tuberculosis) activity. They are compounds consisting of iodine and usually detergents to which the iodine quickly binds. Iodophor preparations are less irritating to tissues, cause less allergies, and do not normally stain skin or clothing. They should not be used on white or pastel vinyls that are subject to staining from repeated exposure to iodine. Their biocidal activity is accomplished within 10 to 25 minutes of exposure. To ensure tuberculocidal activity, fresh solutions must be prepared  daily.  As  iodophors  lose  effectiveness,  the color changes from amber to clear. Iodophors become somewhat unstable at high temperatures and can have a rapid loss of antimicrobial activity when inactivated by hard water and alcohol. Distilled or at least softened water is recommended to dilute the iodophors before using.  Iodophors  are  EPA-registered  and ADA-accepted as surface disinfectants. They may not be used as sterilants. Iodophor antiseptics are useful in the preparation of   oral   mucosa   for   local   anesthesia,   surgical procedures,  and  handwashing.  Not  only  does  the iodophor remove the microbial populations from the skin, but also a residual antimicrobial effect remains on the scrubbed areas. Although iodophors are used as both antiseptics and disinfectants, the same product is never used for both. Note:  All  semicritical  category  items  should receive  high-level  disinfection  as  shown  in  table  10-3. NONCRITICAL CATEGORY ITEMS REQUIRING CHEMICAL DISINFECTION 10-20 Examples of noncritical category items requiring chemical   disinfection   are   the   following:   dental Phenolics are also classified as an intermediate- level disinfectant, provided the product label indicates a  claim  to  tuberculocidal  activity.  They  act  as  good surface spray cleaners and are effective in the presence of detergents. Phenolics are useful on metal, glass, rubber, and plastic, and are less toxic and corrosive than glutaraldehyde solutions. However, they create a film accumulation, can degrade certain plastics, and etch glass with prolonged exposure. They are very irritating   and   contact   with   skin   and   mucous membranes should be avoided. To prevent skin and eye irritation, protective gloves and eyewear must be worn during their use. SEMICRITICAL CATEGORY ITEMS REQUIRING CHEMICAL DISINFECTION Examples of semicritical items requiring chemical disinfection are three-way syringe tips, high-volume evacuator (HVE) and saliva ejector tips, radiographic positioning devices. For the chemical disinfection of semicritical items, use the following procedures: Follow the manufacturer’s instructions. Thoroughly  wipe  the  item  with  absorbent material  saturated disinfectant. with  an  EPA-registered Allow the disinfecting solution to remain in contact with the item for the length of time specified by the manufacturer. Whenever possible, all semicritical items that can withstand sterilization should be sterilized. Although nitrous oxide masks and breathing tubes fall   into   the   semicritical   category,   if   they   are autoclavable, clean and sterilize them using steam heat. If not autoclavable, wipe after each use with two separate  gauze  pads  saturated  with  a  high-level disinfectant. If breathing tubes are not autoclavable, after each use, rinse inside and outside with running water, wipe and flush with a high-level disinfectant, and rerinse with water.