Oregon envelopes labeled as anthrax being examined

Two envelopes containing white powder and marked "anthrax" were found in Portland, Ore., on Wednesday and have been examined for possible toxic substances.

The preliminary tests on the first envelope, found at the Portland International Airport, found no dangerous substances. The second envelope, discovered at a downtown Hilton hotel, has yet to undergo conclusive tests, Reuters reports.

Offices at the airport were evacuated upon the discovery of the letter, though airport operations were not disrupted. The Hilton offices were also evacuated, but the hotel remained in operation. Earlier in the week, a similarly marked envelope was found in the offices of Lloyd Center shopping mall in Portland. The envelope was found to contain no harmful material.

Paul Corah, a fire department spokesman, did not know if the incidents were related or if the letters were sent through U.S. mail, according to Reuters.

Beth Anne Steele, an FBI spokeswoman, said the bureau is looking into the incidents.

In April, a Vancouver, Wash. nurse pleaded not guilty to allegations that he sent more than 100 threatening letters containing a benign substance to the news media and members of Congress in February. The incident represented the largest postal security scare in Washington since anthrax-laced letters were sent to U.S. Senate and news organization offices in 2001. Five people died and 17 were sickened as a result of the incident.