In an interview, Mr. Tyler said he did no such thing. “We’re supposed to be using science and making science-based decisions,” Mr. Tyler said. He said he wrote the memo and circulated it to agency attorneys whose job it is to be aware of documents that potentially shouldn’t be made public in a lawsuit.

He is trying to get his job back. The Public Employees for Environmental Responsibility, a legal group that works with government environmental whistle-blowers that is representing Mr. Tyler, argues that his removal is illegal retaliation.