Tuesday's ricin scare turns out not to have actually been ricin. Officials announced Wednesday that the suspicious substance found in two envelopes sent to the Pentagon was actually castor seeds, from which ricin is made, but was not ricin itself. The envelopes, which were addressed to the chief of the US Navy, Adm. John Richardson, and to Defense Secretary Jim Mattis, were turned over to the FBI after being flagged at a Pentagon mail screening facility. The Centers for Disease Control and Prevention does warn that if castor seeds are swallowed the released ricin can cause harm, the AP reports. (More ricin stories.)