The environmental Kuznets curve (EKc) has been extensively criticized on theoretical and empirical grounds. In this article, the EKC is reformulated as the best practice technology frontier-countries' distances from the frontier reflect the degree to which they have adopted the best practice technology in emissions abatement. The Kalman filter is used to model the state of sulfur emissions abatement technology in a panel of 15 mainly developed countries. The results are used to determine whether and howfast countries are converging to best practice throughout time and what variables affect the level of technology adopted. The results show that with the exception of Australia, countries are converging toward the frontier but have settled into low pollution abatement and high pollution abatement groups. Preabatement levels of pollution, income per capita, population density, and perhaps cultural factors might partly explain the level of abatement adopted.