Ricin has been detected in two pieces of mail that arrived at a Pentagon mail distribution center, defense officials announced Tuesday. "Those envelopes are now undergoing further testing", the Federal Bureau of Investigation said in a statement.
Ricin is a highly toxic compound that is extracted from castor beans and has been used in terror plots.
The two envelopes were screened and tested for the toxin at a mailing facility which is not inside the main building but is nearby, defense officials said.
Two envelopes believed to contain ricin poison have been sent to the Pentagon. The agency said the envelope "was not received at the White House, nor did it ever enter the White House".
The facility is now under quarantine, defence officials said on Tuesday.
The Buccaneers Will Probably Stick with Ryan Fitzpatrick
Fitzpatrick also started three games last season, going 2-1 while Winston was sidelined with a shoulder injury. So we know what we're going to do.
The packages never made their way into the Pentagon, but were flagged in a mail delivery building next door on Monday, the spokesman said.
'As this is ongoing, we will have no further comment, ' a spokesman said. That same year, US counterterrorism officials said they were increasingly tracking the possibility that al-Qaida would use ricin in attacks against the United States. Ricin can cause death within 36 to 72 hours from exposure to an amount as small as a pinhead.
Shortly after the September 11, 2001 attacks in NY and Washington, letters containing another deadly substance - anthrax spores - were mailed to the Washington offices of two senators and to media outlets in NY and Florida.
Notable Ricin poisonings include the deadly poisoning of Georgi Markov, a Bulgarian writer and journalist who was living in London in 1978.