A Pennsylvania congressman has given the Environmental Protection Agency until Tuesday, the sixth anniversary of the Sept. 11 attacks, to resolve a metal discharge problem at the Flight 93 crash site. Rep. Bill Shuster, R-Pa., is demanding that the EPA grant a waiver for manganese discharge at the site, saying construction of the memorial cannot proceed without it. If the EPA does not grant the waiver by Tuesday, Shuster said he will go ahead with legislation. Thirty-nine passengers and crew members were killed when Flight 93 crashed. Manganese is a naturally occurring metal that can damage the central nervous system. Past surface mining at the crash site caused the discharge. But officials said the levels found there are lower than those considered dangerous.