MACOMB, Ill. (AP) — A Western Illinois University professor is harvesting wild hemp across Illinois for a research project that will evaluate THC levels in the plants.

The Illinois Department of Agriculture has issued Agriculture Professor Win Phippen the department’s only permit to harvest wild hemp, sometimes called “ditch weed,” for research. The plant produces CBD oil, which is not an illegal drug and is widely available for a variety of uses.

Phippen says the project “addresses concerns of high THC hemp being grown in the wild.” Phippen will take cuttings and plant them at WIU, where he’ll evaluate each plant’s THC level and other characteristics. He’ll collect the “clean” seed and make it available to Illinois growers.

Lawmakers legalized industrial hemp last year. Phippen received a grant from WIU to fund the project.