Aims: An effective decontamination procedure of personnel wearing personal protective equipment is required by CBRN responders and healthcare workers when dealing with biological warfare agents or natural outbreaks caused by highly contagious pathogens. This study aimed to identify critical factors affecting the efficacy of peracetic acid (PAA)-based disinfectants and products containing either hydrogen peroxide or sodium hypochlorite under the same conditions. Methods and Results: The influence of concentration, application (contact) time, erroneous human behaviour, interfering substance, technical assets and weather conditions on disinfection efficacy against Bacillus subtilis spores were assessed in 14 experimental groups. Residual contamination of protective suits was measured to provide responders with readily understandable information (up to 100 colony forming units classified a suit as disinfected). Weather conditions, short application time and erroneous human behaviour substantially affected the effectiveness of PAAs (P < 0Á05). Non-PAA-based disinfectants (either liquid or foam) did not reach comparable efficacy (P < 0Á001). Conclusions: Peracetic acid was effective at a concentration of 6400-8200 ppm and an application time of 4 min. Significance and Impact of the Study: The study provides operationally relevant data for the use of PAA-based disinfectants in preparedness planning and management of biological incidents and natural outbreaks.