SACRAMENTO – The California Senate is backing a 15 percent sales tax for medical marijuana.

State officials estimate the bill approved Wednesday would raise about $250 million per year, much of it for state parks, drug treatment programs and the state general fund.

Democratic Sen. Mike McGuire of Healdsburg says his bill will also generate money to help local governments manage marijuana-related problems.

Senators approved SB987 on a 27-9 vote, sending it to the state Assembly.

Critics say taxing medical marijuana will harm poor users who rely on its medicinal benefits.

McGuire says he’ll change the bill in the Assembly to ensure people with low incomes don’t pay the tax.