Chemical terrorist attacks using nerve gas require patients with immediate administration of antidote, or otherwise they will experience abnormal neurological activity, respiratory arrest, and death. When it occurs in large stadiums at mass gatherings such as the Olympics, under normal medical care systems, preventable deaths occur due to insufficient deployment of on-site auto-injectors and stockpiled antidotes in hospitals. In Japan, the government has stockpiled antidotes in confidential warehouses and deployed auto-injectors around possible terrorist sites. When a chemical attack occurs, a stockpile of antidotes go to hospitals, auto-injectors go to the site, and firefighters and police are allowed to administer auto-injectors to patients. However, few studies are conducted on pre-deployment of auto-injectors and antidotes in chemical terrorisms. Therefore, the number of pre-deployment was examined.

A single chemical attack with 750 patients was assumed. Response was divided into five steps: (1) transportation of stockpiles to hospitals, (2) transportation of auto-injectors to the site, (3) on-site use of auto-injectors, (4) transportation of patients to hospitals, and (5) patient care in hospitals. Computer estimation was used for the time required for transportation for (1), (2), and (4). Desktop exercises were conducted for on-site response time, outpatient response time, and the number of beds available at hospitals for (3) and (5). The values obtained from computer estimation and desktop exercises were imported into the simulation model to measure the number of paramedics, auto-injectors required to be deployed in advance, and the amount of stockpiles required to be delivered to hospitals.

A minimum of 80 auto-injectors and ten paramedics were required to be pre-positioned at the scene. A minimum of 100 ampules of antidote was required immediately at the nearest hospitals.

The pre-deployment of auto-injectors and personnel are essential to reduce the number of deaths in the event of chemical terrorisms.