The U.S. Army psychiatrist James S. Ketchum, who worked for almost a decade on the U.S. military’s top secret psychochemical warfare program, relates a story relevant to the concept of a “knockout gas” in his 2006 memoir, entitled "Chemical Warfare Secrets Almost Forgotten". In 1970, Ketchum and his boss were visited by CIA agents for a brainstorming session at his Maryland laboratory. The agents wanted to know if an incapacitating agent (his specialty) could be used to intervene in the ongoing hijacking of a Tel Aviv aircraft by Palestinian terrorists without injuring the hostages. Accordingly: We considered the pros and cons of using incapacitating agents and various other options. As it turned out, we could not imagine a scenario in which any available agent could be pumped into the airliner without the hijackers possibly reacting violently and killing passengers. Ultimately, the standoff was resolved by other means.