Defendant challenges his convictions for using a chemical weapon in violation of 18 U.S.C. section 229(a) and making false statements to the FBI in violation of 18 U.S.C. section 1001. Defendant contends that Congress exceeded its authority when it passed section 229(a) to criminally enforce provisions of the Chemical Weapons Convention. Defendant's convictions and sentence are affirmed, where: 1) the prosecution pursuant to section 229 was within the federal government's prosecutorial authority, and Congress has the constitutional authority to proscribe the conduct in which defendant engaged, as defendant's detonation of chlorine bombs requiring the evacuation of an entire neighborhood had the potential to cause severe harm to many people; 2) section 229(c) does not require the government to prove that defendant's criminal act was against property owned, leased, or used by the United States; 3) the information supporting probable cause to search was not stale because it was based on defendant's continuing pattern of criminal conduct, and the warrant application sufficiently limited the agents' discretion in conducting their search; 4) the statements of defendant's co-participant were admissible pursuant to Federal Rules of Evidence Rule 801(d)(2)(E) as co-conspirator statements even though the indictment did not allege a conspiracy count; and 5) application of a two-level obstruction of justice enhancement pursuant to U.S.S.G. section 3C1.1 did not constitute impermissible double-counting.