U.S. Sen. Charles Schumer (D-N.Y.) said yesterday he would join with U.S. Sen. Barbara Boxer (D-Calif.) to block President Bush’s nomination of Donald Schregardus to be the U.S. EPA’s chief enforcement officer. Schumer said he would use parliamentary tactics to stall the nomination until the Bush administration indicated whether it would withdraw from Clinton-era lawsuits against power plants in the Midwest and the South that send pollution to the Northeast. As Ohio’s top environmental enforcer, Schregardus opposed efforts by the EPA to regulate the Midwest brew of pollution that blows east. Environmental groups say Schregardus generally had an abysmal record at his Ohio post.