The FBIs Washington Field Office said in a statement that federal agents are investigating a suspicious letter received at a U.S. government mail facility. At this time, there is no known threat to public safety.
The U.S. Postal Inspection Service is also investigating, officials said. Mail addressed to the White House is prescreened and tested for dangerous substances at an off-site mail facility.
There have been a spate of ricin mail cases in the past decade, including one in 2013 in which a man in Mississippi sent a letter with ricin to President Barack Obama as part of a strange plot to frame an Elvis impersonator with whom he was feuding.
Ricin can be deadly if ingested or inhaled, but touching it is unlikely to be fatal. There is no antidote for ricin. Symptoms of ricin poisoning include difficulty breathing, fever, diarrhea, and vomiting.