Story highlights Law allows Californians to petition for misdemeanors to be expunged, felonies reduced

DA says process can be cost prohibitive for citizens, so his office will do the work

(CNN) Good news for people who had a marijuana-related conviction in San Francisco during the past 40-plus years.

There's a good chance it will be removed from their records or be downgraded.

On Wednesday, San Francisco District Attorney George Gascón said his office is going to look into thousands of cases dating back to 1975, retroactively applying a new California law legalizing some recreational cannabis possession.

The new law allows people whose past crimes would now not be penalized in the same way to petition to have their convictions overturned or reduced from a felony to a misdemeanor.

But Gascón said his office is going to be proactive and do the legwork for the people affected.

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