Decontamination Validation of the BSL-4 Chemical Disinfectant Deluge Shower System

Positive pressure breathing-air-fed protective suits are used in biosafety level 4 (BSL-4) containment laboratories as personal protective equipment to protect workers from high-consequence pathogens. However, even with the use of primary containment devices, the exterior surfaces of these suits could potentially become contaminated with those pathogens and result in their inadvertent removal from containment. To address the risk of such pathogens escaping from containment via contaminated protective suits, these suits are decontaminated in a disinfectant chemical shower situated in an anteroom prior to exiting the BSL-4 laboratory. Properly diluted chemical disinfectants such as Micro-Chem Plus™ (MCP) or peracetic acid are used for this purpose. However, whether these suits are properly decontaminated during the chemical shower process needs to be validated.

The purpose of this study was to develop a suit decontamination validation method for the BSL-4 chemical showers using a risk group 2 (RG2) surrogate virus for the high consequence pathogens that are handled in the BSL-4 laboratories. Here, we evaluated the efficacy of a 5% MCP shower using coupons made from different parts of protective suits (suit fabric, visor, boot, vinyl tape) laden with a dried-on mixture of vesicular stomatitis virus in tripartite organic soil load.

This validation study demonstrated that a chemical deluge shower procedure using 5% MCP for 2 min followed by a 3-min water rinse was successful in decontaminating the positive pressure suits that were experimentally contaminated with the live RG2 virus. This offers valuable insights into the rigor of the decontamination process being undertaken in the BSL-4 laboratory chemical showers.