MADISON, Wis. (WRN) — Republican lawmakers seek to close a legal loophole allowing sale of hemp-derived THC products.

Numerous businesses have sprouted in Madison and elsewhere, offering sale of legal hemp-derived THC products like delta-8 and delta-10.

Hemp, in the same plant family as marijuana, is not considered a controlled substance if the THC concentration is less than 0.3%. The bill would add hemp to the definition of THC and would specify that only hemp grown for industrial or research purposes qualifies as “industrial hemp.”

The authors cite last October’s accidental delta-9 THC oil contamination at a Dane County pizza parlor in which dozens of people sought medical attention as an example of why the law change is needed.