a particular degree and kind of pollution for example in this regard substances rich in protein have a restricting action on the antimicrobial effect of the disinfectant agent and consequently the concentration is generally increased in such a situation illustrative of useful antimicrobial agents is a water solution of 5 chloramine or a 1 2 to 2 4 chlorinated trisodium phosphate and potassium bromide solution sold under the trademark of k644 these particular agents are especially effective for use with hepatitis virus infected material beta propio lactone bpl is active against vegetative organisms and bacteria spores as well as virus bpl is used in an 0 2 1 water solution the purest form of bpl 3 5 mg per ml acts synergetically with ultraviolet light in the destruction of serum hepatitis virus in blood from blood donors it hydrolyzes completely to non toxic acid products when heated to above 37 u00b0 c chlorhexidine in concentrations of 0 1 1 w v are active against gram positive and gram negative organisms chlorine compounds such as hypochlorites organic and inorganic chloramines such as chloramine t and halazone and nh 2 cl and nhcl 2 respectively are also useful in the method of this invention their effect is considerably increased by the presence of inorganic bromide and they affect bacteria virus and to a certain extent also bacteria spores sodium hypochlorite solution generally should contain 1 20 free chlorine sodium hypochlorite 1 can be stabilized by the addition of nacl 16 5 which also corrodes metals and accelerates solidification of plaster useful as a solid compound a formaldehyde solution is effective against bacteria spores and is in addition suitable for disinfecting.