Cost Effectiveness of On-Site Chlorine Generation for Chlorine Truck Attack Prevention

A chlorine tank truck attack could cause thousands of fatalities. As a means of preventing chlorine truck attacks, I consider the on-site generation of chlorine or hypochlorite at all U.S. facilities currently receiving chlorine by truck. I develop and apply mathematical models to estimate the amount of chlorine shipped by truck in the United States and the cost of generating chlorine at each facility. I then calculate system costs, as well as cost effectiveness in terms of expected cost per death avoided. The median estimated amount of chlorine trucked in the United States is 500 thousand tons/year, with 80% going to water and wastewater treatment. The median net cost of on-site generation totals $800 million/year for the United States as a whole. On-site generation would pass a cost-effectiveness test requiring median estimated cost per death averted to be $6.5 million or less if the investment reduces the annual probability of a chlorine truck attack in the United States by at least 0.03, depending on the chlorine attack simulation dose--response model and other factors. The expected value of the reduction of fatality risk from truck accidents causing chlorine releases would be $8 million per year, too low for cost effectiveness if that is the only benefit of on-site chlorine generation.