Federal courthouse in downtown Philadelphia partially evacuated after anthrax scare

An envelope containing white powder recently led to the evacuation of a portion of the Federal Courthouse in Center City, Philadelphia.

Executive Fire Chief Richard Davison said that a prisoner in the building allegedly sent the letter to an office on the second floor, claiming it contained anthrax. A hazardous materials team responded to the incident and investigators determined the envelope posed no threat, according to Philly.com.

Davison said that the powder was non-hazardous, but could not say what it was. No illnesses were reported. The second floor was evacuated and traffic stopped around the site, but the all-clear was given approximately an hour later. The U.S. Federal Bureau of Investigation was notified and is looking into the incident.

Center City, Philadelphia, includes the city's central business district and several historic neighborhoods. It is one of the most populous downtown districts in the United States, Philly.com reports.

Anthrax refers to the disease caused by the bacterium Bacillus anthracis. The bacterium can form spores that remain dormant for long periods of time in extreme conditions. Anthrax occurs naturally, but is considered a potential weapon of bioterrorism, according to the U.S. Centers for Disease Control and Prevention.

The CDC classifies anthrax as a Category A agent, meaning it poses the greatest possible threat to public health. Anthrax was used as a weapon in 2001, when it was spread through the postal system. The attacks caused 22 cases of infection, five of which resulted in death.