The owner of the largest butane supply company in the United States plead guilty to a drug charge related to the manufacture of hash oil on Thursday. Bosco Kwon, owner of BK Power Imports, Inc., was being charged with knowingly supplying butane to hash oil extractors across the U.S., according to the Department of Justice.

BK Power Imports sold butane under the Power brand in Power, Power 5x, Power 7x, Power 9x, and Power 11x varieties. The company imported more than 350,000 butane canisters into the country every month. Kwon admitted to selling butane wholesale to smoke shops across the country.

Though hash oil is kind of legal in California, where Kwon was tried, manufacturing a controlled substance is still illegal in both federal statutes and California ones as well. But it seems that it’s that the government was a lot less concerned with making a little wax than they are with the explosions.

Since 2011, Homeland Security Investigations estimates that extractions using Power butane caused “at least 54 fires and explosions, 29 serious injuries, and four deaths in California, Oregon, Nevada, and Washington.” Kwon’s legal trouble seems to have begun in 2015 when he and his company were sued over a serious BHO explosion which killed one extractor and severely burned another.

“Hash oil manufactured with butane gas has led to an alarming number of explosions and fires in recent years,” Dave Shaw, special agent in charge for HSI San Diego, told DOJ. “HSI is committed to targeting the supply chains where butane gas is sold on the black market for use in hash oil labs. By going after the supply chains and the illicit proceeds, we are able to dismantle the distribution networks, which is a critical step toward shutting down a dangerous epidemic that has put the public’s safety in harm’s way for too long.”

This is not the first major butane supplier to come under fire from the government. Puretane’s CEO and CFO were found guilty of laundering money last year, a fact the federal government seems pretty happy with. The DOJ’s statement on Kwon and BK Power concludes: “With these prosecutions, Homeland Security Investigations and the U.S. Attorney’s Office for the Southern District of California have shut down the nation’s two leading suppliers of butane designed for use in making hash oil.”

As part of Kwon’s plea agreement, he will have to forfeit over a million dollars and nearly 100,000 canisters of butane. Sentencing is set for April 28. It’s uncertain what impact this will have on the supply or cost of butane in the future.