What is ricin, found in a package addressed to the White House?

Ricin, contained in a package addressed to the White House, was intercepted by investigators on Saturday, the FBI said.

The poison, found in castor beans, could “potentially be used as a biological weapon,” according to Dr. Pritish K. Tosh of the Mayo Clinic.

“It can be turned into an aerosol and inhaled,” Tosh wrote. “It can also be ingested from poisoned food or a contaminated water supply or injected.”

Ricin is not contagious.

All mail sent to the White House is sorted and screened off-site. Investigators believe the package was sent from Canada, The New York Times reported.

Ricin has been illegal since July 2019, according to The Associated Press.

According to the U.S. Centers for Disease Control and Prevention, ricin is part of the “waste mash” that occurs when processing castor beans into castor oil. It would take “a deliberate act to make ricin and use it to poison people," the agency said.

“Unintentional exposure to ricin is highly unlikely, except through the ingestion of castor beans,” the CDC said on its website.

There is no vaccine or antidote for ricin, and the poison can kill a person within 36 to 72 hours after exposure, the CDC said.

“Ricin is very toxic. It works by getting inside the cells of a person’s body and preventing the cells from making the proteins they need,” the agency said. “Without the proteins, cells die. Eventually, this is harmful to the whole body, and may cause death.”

Symptoms of ricin poisoning can vary, depending on whether a person inhales or ingests it, according to the Mayo Clinic. Inhaling ricin can cause respiratory problems. Organ damage and intestinal bleeding can occur if a person ingests the poison.

“Even a small amount can be fatal,” according to the Mayo Clinic.

“Ricin is an incredibly dangerous biological toxin -- just a few tiny grains can kill a human,” U.S. Attorney Nick Hanna said in a 2019 news release when a California man pleaded guilty to attempting to buy the toxin, according to USA Today.

Ricin was introduced into pop culture when its use was depicted in the television show, “Breaking Bad,” the newspaper reported.

“Because it can be used as a weapon of mass destruction, and there is no antidote for ricin poisoning, any attempt to acquire this deadly chemical agent is an extremely serious matter that will prompt a vigorous response,” Hanna said in his release.

In 1978, Bulgarian journalist Georgi Markov, who was living in London, died after he was attacked by a man with an umbrella, the CDC reported. The umbrella had been rigged to inject a ricin pellet under the writer’s skin.

The U.S. military also experimented with the poison during the 1940s, according to the CDC.