Former E.P.A. Official Pulls Out of House Hearing

Dr. Armendariz had previously agreed to serve as a witness at the subcommittee hearing. He did not respond to requests for comment on Wednesday.

It went without saying that many expected Mr. Armendariz to face a crucifixion, rhetorically speaking, at the hearing. Its Republican leadership has been sharply critical of the E.P.A.’s efforts to enforce the Clean Air Act and tighten emissions standards.