Not this again: The FBI is investigating the discovery of envelopes of white powder sent to eight federal buildings in seven cities in Washington, Idaho, and Utah. The buildings housed IRS and U.S. attorney's offices, and the FBI says it is safe to assume the envelopes are connected. No injuries were reported, though two of the buildings were evacuated. A field test showed the main ingredient of the powder is calcium carbonate, a chalky substance found in limestone. The FBI says it’s taking the incident very seriously. In 2001, anthrax mailed to media and Senate offices killed five people.