Virginia police are familiar with the concept of blood alcohol content, the percentage of alcohol in a person's blood. If tests show a person has a BAC of more than 0.08%, the person is legally deemed to be drunk and cannot drive. Now, Virginia police have a different problem that also depends upon chemical concentration - the difference between industrial hemp and marijuana.
After the Virginia legislature passed legislation allowing the possession of industrial hemp, the number of licensed hemp growers in Virginia has increased from fewer than 100 a year ago to more than 700. These farmers are expected to plant 7,000 acres with a plant that, until a few years ago, was regarded as the hallucinogenic drug marijuana. Hemp is virtually the same plant as marijuana, but the concentration of THC makes one a useful and lawful chemical, and the other a prohibited drug. Industrial hemp has a maximum THC content of 0.3%, and possession of this plant is legal. Marijuana, on the other hand, is cannabis with a THC content greater than 0.03%. Possession of the former, if the owner has a hemp license, is lawful; possession of the latter under all circumstances is illegal.
One of the principal problems is the lack of a reliable field test that police can use to verify the THC content of a hemp plant. Several different tests are being evaluated, but none has been selected. Police have a test that they say can detect the presence of marijuana in a suspect's blood stream, but it cannot tell the difference between marijuana and industrial hemp. A person charged with possession of marijuana can escape conviction if tests can establish that the plant in question has a THC concentration lower than the legal limit of 0.3%. Police are still wondering how they can tell the difference before making an arrest.