This paper presents an approach for determining the sensitivity of maximum net profits to uncertainty in the waste treatment costs in a chemical process. It is shown that a basic relationship exists between sensitivity analysis and the solution of a multiobjective optimization problem that simultaneously minimizes waste production and maximizes the profits before waste treatment. It is shown that all solutions of the sensivity problem lie on the convex hull of the tradeoff curve generated by the multiobjective optimization problem, and that the sensitivity curve can be generated from the tradeoff curve with a simple transformation. The paper presents a sequential approximation method that rapidly calculates the tradeoff curve. The method is illustrated with four examples.