Sponsors of a marijuana initiative have made plans to bring in petitions on Dec. 29 at 10 a.m. at the state Elections Division office at 520 Union St. near the state Capitol in Olympia.

UPDATE: The initiative sponsors are delivering the petitions at 2 p.m., not 10 a.m.

Initiative to the Legislature 502 would authorize the state liquor control Board to regulate and tax marijuana for those 21 and older. Production, possession, delivery, distribution and sale of marijuana in accordance with the provisions of the new law would be decriminalized.  Sponsors say it would generate at least $215 million a year in tax revenue, roughly $80 million for the state treasury and the rest for research, health care, and related purposes.

It takes 241,153 valid signatures of registered Washington voters to be certified, although the Elections Division recommends at least 320,000, to cover duplicate or invalid signatures. If certified, the measure would go to the upcoming regular session of the Legislature, which would have three options: Pass it into law; ignore it or vote it down, sending it to fall, 2012, statewide ballot; or send it and a legislative alternative to the ballot.

Sponsors include former U.S. Attorney John McKay, travel guru Rick Steves and others.