The Secretary of Labor moved to dismiss the petition for lack of jurisdiction on the ground that, because of the remands to determine the amount of wages owed to various employees, the Commission's orders are not final. A screening panel of this court denied the motion. See RSR Corp. v. Donovan, 733 F.2d 1142 (5th Cir. 1984). We have since heard oral argument, and we turn now to an analysis of the merits of RSR Corporation's petition for review. Because we find that the Commission's interpretation of the lead standard is reasonable and that its findings of fact are supported by substantial evidence, we affirm the orders in all respects.