The misunderstandings can lead to frightening encounters. Jim Castetter found himself surrounded by state troopers as he loaded bales of hemp onto a truck at the edge of their farm in Canandaigua, N.Y., said his son, Kaelan Castetter , 23, a co-founder of the New York Cannabis Growers and Processors Association.

“It took about two hours to explain that no, we are not loading the largest quantity of marijuana that the county had ever seen on the side of the road in broad daylight,” he said.

That incident led the family to invite the local police to its hemp-drying facility in Binghamton for a tour this year, Kaelan Castetter said, hoping to combat confusion with education. His interactions with the police have since been largely positive. “They understand the direction that the state and the country is moving in,” he said.

Many law enforcement officials have been hindered by their inability to properly test hemp plants; most still use tests that can often detect only the presence of THC, not its level of toxicity.

In Texas, confounded by the lack of testing equipment, prosecutors began dropping some marijuana charges over the summer, unsure what substance they were dealing with.

“Ensuring law enforcement can differentiate between industrial hemp and its illicit cousin is critical,” Senator Mitch McConnell, the Republican majority leader from Kentucky, said in September when he added language to a 2020 Senate appropriations bill directing the Drug Enforcement Administration to come up with technology that can distinguish between the two types of plants.