A bill proposed by California State Senator Mike McGuire (D-Sonoma County) seeks to impose a 15 percent excise tax on all marijuana transactions, according to LA Weekly.

The city of Los Angeles already has a 5 percent tax on all medical marijuana donations and the state takes a 7.5 percent tax (same as every other taxed goods). That means that an Angelino patient acquiring a legitimate sack of herb would end up paying a 27.5 percent tax if the new bill goes through.

That’s a lot, but far from unheard of. The leading proposal to legalize recreational marijuana in California also comes with an excise tax of an identical amount. And Colorado, which pulled in $135 million in cannabis taxes last year, also imposes a 15 percent excise tax on its reefer goods. A special tax on marijuana is probably unavoidable in California.

What’s unusual, however, about McGuire’s proposed tax is what it’s supposed to be used for. While Colorado reserves all of its proceeds from the excise tax for school construction projects, McGuire wants to use the money to fund a marijuana regulation office in the state government, the impending “regulation of cultivation, processing, manufacturing, distributing and sale of marijuana,” according to a statement from the senator’s office.

A bureaucratic division that regulates medical and (potentially) recreational marijuana in California is called for legally by the Medical Marijuana Regulation and Safety Act (MMRSA) signed by Governor Jerry Brown at the end of last year. So, some funding needs to go toward maintainng that office.

But the hundreds of millions of dollars that would be raised by McGuire’s proposed excise task seem like a little bit of overkill to get the job done. California NORML and Coalition for Cannabis Policy Reform (CCPR) both oppose the new tax. CCPR chair Dale Sky Jones said the tax hike is likely to make patients consider the black market as an alternative.

“I understand that we need to pay for regulation,” she said. “However, slapping a sin tax on patients is not the way to do it. The patients who cannot find quality medicine at a reasonable price will find quality medicine at a reasonable price.”

Jones also pointed out that starting in 2018, all California dispensaries will be required to pay for state permits. “The permitting fees are supposed to cover the cost of the regulation,” she said.