Biological Safety Manual - University of Florida

Formaldehyde gas kills all microorganisms and spores but not prions. It is used for spacedecontamination and to decontaminate biological safety cabinets. This method of decontamination is anextremely dangerous process requiring properly trained, experienced personnel. Formaldehydedissolved in water is active at 1-8% solutions and can be used to decontaminate hard surfaces.However, because formaldehyde is an irritant at low concentrations (0.1 to 5 ppm) and a probablecarcinogen, its use as a hard surface disinfectant is limited to situations in which it is particularly needed.Due to its toxic effects, there are no EPA-registered disinfectants that contain formaldehyde.GlutaraldehydeMost commonly used for high level disinfection of medical equipment, e.g. endoscopes. Glutaraldehyde isusually supplied as a 2% solution and requires activation by the addition of an alkaline agent prior to use.The activated product may be stored for about 1-4 weeks and should be discarded when turbid.Glutaraldehyde is active against all microorganisms, but is toxic, an irritant, and mutagenic and should beused only when necessary. The manufacturer’s guidance must be followed when using glutaraldehydebasedproducts as there are many different formulations that have been designed for specific uses.Hydrogen peroxideHydrogen peroxide is usually available as a ready-to-use 3% solution or as a 30% solution to be diluted1:5-1:10 to decontaminate work surfaces of laboratory benches and biosafety cabinets. It is activeagainst a wide array of microorganisms. However, it is a strong oxidizing agent and should not be usedon aluminum, copper, zinc, or brass. Hydrogen peroxide is unstable at high temperatures and in light.Iodine and IodophorsIodine and iodophors are compounds in which the iodine is combined with a solubilizing or carrier agentand are general all-purpose disinfectants with an action similar to that of chlorine products. Theappropriate concentration for iodine-containing products is 75 ppm available iodine for disinfecting worksurfaces. Concentrations may be much higher for other purposes. Like chlorine compounds, theeffectiveness of iodine compounds may be diminished in the presence of protein/organic material.Iodophor compounds that are used for antisepsis (germicide applied to tissue or skin) are not appropriatefor use as hard surface disinfectants and vice versa. Read the product material for appropriate dilutionsand applications.Phenolic compoundsPhenolic compounds are active at 0.2 - 3% concentrations against all forms of vegetative microorganismsbut not against spores. They have limited effectiveness against non-lipid viruses and when properlyformulated are anti-mycobacterial. There are many common disinfectants based on phenol and theyshould be used according to the manufacturer’s recommendations.Quaternary ammonium compoundsCompounds in this class are active at concentrations of 0.1 - 2%. They are active against vegetativebacteria and lipid viruses, but not against bacterial spores, non-lipid viruses, or tubercle bacilli. Thesecompounds should be used only when a low-level disinfectant is required.Vapor Phase Hydrogen Peroxide Requires specialized equipment Temperature: 4°C-60°C Concentration: 30%, less than 10 mg/liter Non-toxic end products of water and oxygen Limited to surfaces, no penetration Corrosive to some materials Degrades natural rubber and nylonChlorine Dioxide gas Dilute chlorine gas and sodium chlorite, less than 25 mg/liter Temp 25°C-30°C, pre-humidification required Limited to surfaces, no penetration Corrosive to some materials Mucous membrane irritant41