The following hoaxes have been perpetrated using anthrax as an implied threat.
- April 24, 1997: A petri dish containing red slurry labeled Anthracis Yersinia was sent to B'nai B'rith international offices headquartered in Washington DC. The dish actually contained Bacillus cereus, an anthrax simulant.  
- October 10, 2001: An office building in Montreal is evacuated after Globe International receives an envelope from American Media in Boca Raton. The envelope is not opened, is recovered by firefighters, and is later found to be harmless.
- October 12, 2001: The New York Times briefly closes its offices after Judith Miller, a reporter who coauthored "Germs: Biological Weapons and America's Secret War", receives an envelope postmarked October 5 from St. Petersburg, Florida containing a white, sweet-smelling powder. The letter was addressed with crude handwritten block letters, with no return address. She opens it at 9:15 a.m. EDT and the powder coats her face and hands. It is later found not to contain anthrax. 32 employees were tested, and none was found to have been exposed to anthrax.
- October 17, 2001: The FBI arrests a third person for sending a hoaxed anthrax letter. The Rhode Island man mailed it to his friend, who called 9-1-1.
- October 18, 2001: In Nairobi, Kenya, the Kenyan health minister announces that a letter sent from Atlanta to a Kenyan citizen tested positive for anthrax spores. Two other suspicious envelopes were tested, one of which was sent to a Nairobi United Nations office. These all tested negative.
- December 2001: Clayton Lee Waagner, 45, was arrested for sending more than 550 anthrax hoax letters to abortion clinics.
- March 13, 2002: The FBI announces that 10 fake anthrax letters were mailed to various Hispanic organizations in the past two days. These letters all contained a white powder that was not anthrax. Although no one is arrested yet for this crime, at least 35 others have been arrested in the U.S. for similar hoaxes.
- April 26, 2005: A newspaper in Midland, Michigan was closed and quarantined briefly after a suspicious letter with white powder and the word "ANTHRAX" written on it arrived in the mailbox. It was later determined that the letter did not contain anthrax. The white powder was believed to be from foot powder.
- September 26, 2006: Keith Olbermann, Jon Stewart, Sumner Redstone, David Letterman, Nancy Pelosi, and Charles Schumer received letters with a California postmark which contained a batch of white powder and a note warning Olbermann. An NYPD HazMat unit indentified the substance as soap powder. A suspect, Chad Castagana, has been arrested in relation to this event.
- November 27, 2006: The Lincoln Memorial in Washington, DC was closed down temporarily when a suspicious liquid was found near an envelope which had "Do you know what anthrax is?" and "Do you know what a bomb is?" written on it. The items were later found to pose no threat to public health and were not a biological threat.
- February 27, 2007: The University of Missouri–Rolla campus in Rolla, MO was closed down and classes were canceled when a student made a bomb threat and had a white powder which he claimed to be anthrax. The bomb threat turned out to be a hoax and the white powder was ordinary powdered sugar.
- May 25, 2007: A package placed outside of Emmaus High School in Emmaus, PA contained a white substance and has a message saying "ANTHRAX" written on it. No students in the school were evacuated upon finding the package or throughout the event. Lehigh County Hazmat came and determined that the substance was not anthrax but instead a hoax. Throughout the event, there was no threat to any students.
- August 23, 2007: Two siblings in New Haven, Ct. are arrested after one of them is spotted dropping puffs of flour within an IKEA store parking lot. Police later found out they were members of the Hash House Harriers, an international off-beat running club that uses flour to mark the running trail. They were charged with felony first-degree breach of peace.