If voters in Washington State approve I-502, an initiative to legalize, tax and regulate marijuana, it could generate over half a billion dollars in new revenue a year for the government. That’s the conclusion of a new partial fiscal note from the state’s Office of Financial Management. (hat tip to Dominic Holden at the Slog)

The analysis assumes that if marijuana is legalized in the state, roughly 85.1 to 93.6 million grams of marijuana would be sold a year in the state. The legal production and retail sale of marijuana would generate significant amounts of revenue for the government through both a new excise tax placed on cannabis and current sales and business taxes.

Depending on levels of consumption the excise tax placed on marijuana is projected to generate roughly $434 million to $463 million in the first full fiscal year after the law is implemented. About half a million would be collected from new licensing fees. The bulk of this new revenue from the excise tax would go towards funding programs helping individuals obtain health care.

In addition to the excise tax, passage of I-502 would generate roughly $10 million from the business & occupation tax. It would also generate between $120 to $133 million from state and local retail sales taxes.

In total this partial estimate projects that the legalization of marijuana would bring in around $560 to $600 million in new tax revenue for the government. This would be a substantial financial infusion to the cash strapped state. For comparison the entire annual budget for Washington state is roughly $35 billion.

These are only preliminarily, partial estimates by the state. There are many unknown variables that could affect how much tax revenue I-502 will generate if approved.