MANLIUS TOWNSHIP, Mich. (AP) — Police say an explosion at a storage unit where medical marijuana was being grown has injured a man and killed his dog in western Michigan.

The man had no ties to the marijuana and was visiting a different unit Thursday in Allegan County’s Manlius Township.

Kristopher TenHarmsel tells WOOD-TV that he was growing “fully legal” medical marijuana. He believes the explosion was caused by a malfunctioning heater that uses propane.

TenHarmsel says the explosion destroyed his plants and equipment. The explosion could be heard for miles. Debris was found hundreds of yards away.

Doug DeJonge, who lives next to the storage facility, tells the Holland Sentinel that his house shook and pictures fell off the wall.