Benefit-cost analysis of the Stage 1 D/DBP Rule

In December 1998, the U.S. EPA promulgated the Stage 1 Disinfectant /Disinfection By-Products (1 D/DBP) Rule to minimize DBP. The rule would achieve this primarily through low-cost modifications, including enhanced coagulation and moving the point of disinfection, rather than advanced technologies. Although the D/DBP Rule would cost about 700 million U.S. dollars to implement, its benefits would be worth more. Human exposure to DBP was likely to fall 24 per cent, with a projected fall in bladder cancer probably worth 4 billion U.S. dollars. The rule's benefits and costs were analysed by 5 approaches: an overlap analysis of costs and benefits; a break-even analysis of how much bladder cancer risk would have to be reduced for the rule to pay for itself; the cost of compliance for each household; a calculation of annual net benefits from an evaluation of rule cost, exposure reduction and attributable bladder cancer risk; and an analysis of the maximal financial consequences if the supporting assumptions were wrong. Health risk uncertainties made the derivation of definitive answers difficult.