The use of the Russian nerve agent Novichok in the assassination attempt of double agent Sergei Skripal in the quiet city of Salisbury, England was a violation of international law banning the use of chemical weapons. Specialist Hamish de Bretton-Gordon, who works for a company that supplies gas masks to the U.S. military, calls it a turning point. "The hundred-year taboo on the use of chemical weapons has been completely broken," he said. Gordon said it only took a couple of drops of Novichok to shut down parts of Salisbury for months. "If it can happen in Salisbury…it can happen in Baltimore or Philadelphia," he added. Aimen Dean, a former al Qa’ida member-turned British spy, said the Salisbury attack will inspire terrorists. "The Novichok attack was a big neon sign, advertisement basically, for al Qa’ida and [the Islamic State]," he said. "They've already tried three or four times in the last several years and they will try again.” CBS News.