The Effect of Legal Hemp on Drug Dog Sniffs (Part I)

Hemp and hemp products are now legal under state and federal law. Hemp is the same plant as marijuana and contains the same chemical compounds, though in different concentrations. Could a drug dog trained to detect marijuana alert on legal hemp? If so, does that impact whether a dog sniff is a search under the Fourth Amendment? And does it mean that a drug dog’s alert no longer provides probable cause to search a vehicle? This two-part series tackles those questions. A dog could alert on legal hemp. So says the State Bureau of Investigation in this memo: “Police narcotics [K-9s] cannot tell the difference between hemp and marijuana because the [K-9s] are trained to detect THC which is present in both plants.” Other sources reach the same conclusion. See, e.g., Bill Bush, Is it hemp or is it pot? Drug dogs can't say, Columbus Dispatch (Aug. 12, 2019) (reporting that “[b]ecause marijuana and hemp are both from the cannabis plant and smell identical, dogs can’t tell the difference, so both the Ohio Highway Patrol and the Columbus Division of Police are suspending marijuana-detection training for new police dogs to uncomplicate probable cause issues in court” and noting that the Columbus City Attorney has directed that “a vehicle may not be searched solely because a K-9 trained to alert to marijuana, alerted to the vehicle”); Jennifer Kendall, Legal hemp could affect Texas’ drug detection dogs, Fox 7 Austin (July 3, 2019) (“The Texas District and County Attorney’s Association said drug dogs [...]