Man Drives Truck Onto National Mall Claiming Anthrax Possession

A man drove his vehicle onto the National Mall in Washington D.C. Tuesday, claiming he had anthrax in his vehicle, law enforcement sources tell ABC News.

The man said he believes he was exposed to anthrax on a rural farm in Virginia, where he says he saw the substance being spread on a field, according to U.S. Park Police spokesperson Sgt. Anna Rose. The man then collected the substance and brought it to the National Mall "in order to warn others of the danger," Rose said.

The man did not present a threat to the public, Rose said.

Initial field tests for the substance were negative. The man was swabbed, checked for anthrax and was cleared of any infection, but will have to undergo a decontamination process by Washington, D.C. officials before being taken to a hospital, Rose said. Police officers who came in contact with him will also undergo the decontamination process.

Authorities interviewed the man and cleared the scene of any other potential hazards. The white four-door truck remained in place as police robots investigated whether it contains a substance "to be concerned with," Rose said. At this stage in the investigation, it is unclear if the truck contains anthrax, she added.

The man sent an email or letter indicating he thought he was exposed to anthrax, Rose said, but it is unclear who the correspondence was intended to or when it was sent.

The incident was called in to police by several passersby who witnessed it.

Roads and walkways in the area will be closed for at least the next few hours, Rose said.