The EPA set emission standards for vinyl chloride, a toxic substance that is carcinogenic to humans. The Clean Air Act says such standards must be "at the level which.provides an ample margin of safety to protect the public health." The exact threat from vinyl chloride was not known. The EPA said that the proper emissions requirement is the lowest level attainable by best available control technology.
The Natural Resources Defense Council sued, contending that since there was uncertainty about the danger, the EPA had to prohibit all emissions. Which position do you think was held correct? [NRDC v. EPA, 824 F.2d 1146, D.C. Cir. (1987)]