A Pentagon spokesman said authorities had found at least two packages suspected of containing ricin, a poison made from castor beans.

Spokesman Chris Sherwood said the FBI was investigating and few details were available. He said the packages had been found on Monday at a delivery facility that is on the Pentagon grounds but not inside the main building that includes the offices of the defense secretary.

Sherwood said the packages were addressed to a person at the Pentagon. He would not reveal the name.

Ricin is part of the waste “mash” produced when castor oil is made. According to the Centers for Disease Control and Prevention, if it is made into a partially purified material or refined, ricin can be used as a weapon capable of causing death under certain circumstances.

Meanwhile, at least two people were taken to hospital after a suspicious white powdery substance was found in a Houston building where Republican senator Ted Cruz’s electoral campaign office is located, but tests showed the substance to be non-hazardous, fire officials in Texas said on Tuesday.