may not appear for minutes to hours, tissue damage from vesicants occurs within a few minutes, and agent that penetrates the skin is far less amenable to decontamination than the agent that has not yet been absorbed Patient decontamination has two important purposes: prevention or minimization of continuing absorption of agent into the patient and prevention of secondary exposure of healthcare workers By preventing absorption of a lethal dose of agent, immediate decontamination can be the most important lifesaving action available for a chemical casualty This process would ideally occur at the scene; however, in a large-scale terrorist incident, it is far more likely that some victims will self-transport to the ED A special decontamination and treatment area in the decontamination corridor outside or adjacent to the ED markedly facilitates casualty processing and management, and accreditation agencies have mandated that all hospitals provide such decontamination capacity FIGURE 132.5 A rapidly deployable outdoor decontamination facility Capability for thorough decontamination must be available quickly with little setup time Many models have been proposed, but most authorities recommend an outdoor facility with multiple patient stations, arranged so that parallel lines of ambulatory and nonambulatory patients may be processed simultaneously ( Fig 132.5 ) An outdoor facility is more capable of handling multiple patients and may make the use of copious water irrigation easier; however, it may be challenging to protect victims from inclement weather in temperate climate zones, an issue especially important in the management of young children Thus,