GRASS VALLEY — Residents of a small town in rural north-central Oregon were forced to evacuate for nearly 24 hours after a hemp processing plant caught fire, injuring five workers.

The fire started about 3:40 p.m. Sunday at the facility, owned by GVB Biopharma, and continued to burn overnight.

Evacuations were ordered for all of Grass Valley — population 155 — amid concerns that chemicals at the site might explode. Residents were allowed to return home at 11:34 a.m. Monday once officials from the state Fire Marshal’s Office, Department of Environmental Quality and hazmat crews determined it was safe.

Grass Valley is 43 miles southeast of The Dalles.

According to the Sherman County Sheriff’s Office, five employees suffered burns in the fire. Of those, one had “significant burns.”

None of the injuries was life-threatening, said Jim Mish, president and CEO of 22nd Century Group Inc., which owns GVB Biopharma. The cause of the fire is still under investigation.

“We’re in a full assessment mode,” Mish said. “It may take us a while to determine the exact cause.”

GVB Biopharma was founded in 2016 and acquired by 22nd Century Group in May. The company processes hemp for cannabidiol, or CBD, a compound in hemp with purported therapeutic and health benefits.

About 60 people worked at the plant in Grass Valley, Mish said, which mostly produces CBD extracts used as a raw ingredient in products such as lotions, creams and tinctures.

Flames engulfed one building where hemp is processed on the property. Drone footage from the sheriff’s office showed several small explosions. Other assets, including inventory, warehousing and storage, were not affected, Mish said.

The American Red Cross set up an overnight shelter for evacuated residents at Sherman Junior-Senior High School in Moro, 10 miles north of Grass Valley. The fire also temporarily shut down U.S. Highway 97 in the area.

Mish said the company may shift some production to its other Oregon hemp processing plant in Prineville.

“We remain dedicated to Oregon for the long-term,” he said. “Obviously, our main focus right now is around the individuals injured and their families, and working with the emergency response teams that came to the scene.”This is a breaking news story and will be updated.