A massive explosion shook Logan Township, New Jersey, Wednesday afternoon, sending at least four people to hospitals and prompting a shelter-in-place order for residents within a two-mile radius.

The blast occurred at Savita Naturals, a family-owned cannabis oil extraction company that uses highly flammable propane solvent methods.

Authorities reported a partial building collapse and burn victims, with three patients taken to Cooper University Hospital and another to a Philadelphia hospital.

Smoke continues to fill the area as emergency crews respond, and the cause of the explosion remains unknown, the U.S. Sun has reported.

Local officials plan a press conference later Wednesday to provide updates.