To give you an idea of how potent this drug is, carfentanil is commonly used by veterinarians as a tranquilizer for larger animals such as elephants. The amount of carfentanil seized during the October traffic stop was .7 grams.
“Exposure to a very small amount of this drug, about the size of a grain of salt or 20 micrograms, could be fatal though inhalation and ingestion," says Peterborough Police Deputy Chief Tim Farquharson. "There is also concern due to the fact that it can be absorbed through the skin."