Dipentino

Rocco Dipentino and Rafiq Ali appeal their convictions following their joint trial for improperly removing asbestos-containing materials from the Landmark Hotel and Casino in Las Vegas, Nevada, prior to its demolition, in violation of the Clean Air Act, 42 U.S.C. §§ 7412 (f)(4) and (h), 7413(c)(1). The government cross-appeals the sentences imposed by the district court. We conclude that the district court committed plain error when it constructively amended the indictment by instructing the jury on a work practice standard that the defendants were not charged with *1093 violating. We exercise our discretion under Federal Rule of Criminal Procedure 52(b) to reverse the defendants’ convictions and remand the case to the district court. We dismiss the government’s cross-appeals as moot.

BACKGROUND

The Las Vegas Convention and Visitors Authority (“Visitors Authority”) hired Ab-Haz Environmental, Inc. (“Ab-Haz”), an asbestos-abatement consulting firm, to oversee the removal of asbestos-containing materials from the Landmark Hotel and Casino in Las Vegas, Nevada, prior to its demolition. Rafiq Ali 1 was the president and sole proprietor of Ab-Haz; Rocco Dipentino was an industrial…