The worst-case analysis regulation[1] was promulgated in 1979 by the US Council on Environmental Quality (CEQ).
The regulation is one of many implementing the National Environmental Policy Act of 1969[2] and it sets out the formal procedure a US government agency must follow when confronted with gaps in relevant information or scientific uncertainty about significant adverse effects on the environment from a major federal action.
[3] The regulation requires an agency to make known when it is confronted with gaps in relevant information or scientific uncertainty.
[1] The agency then must determine if the missing information is essential to a reasoned choice among the alternatives.
[4] This article incorporates public domain material from websites or documents of the United States Government.