The package was addressed to President Donald Trump.
A facility outside the White House typically screens all mail before it is delivered to the White House.
An official speaking to the New York Times said the letter is believed to have been sent from Canada.
An attempt to mail ricin to President Trump was also intercepted in October 2018.
William Clyde Allen, a former Naval officer was arrested by the FBI for mailing ricin filled letters to Secretary of Defense James Mattis, Chief of Naval Operations Adm. John Richardson, and FBI Director Chris Wray.