Prosecutors in San Francisco will throw out thousands of marijuana-related convictions of residents dating back to 1975.San Francisco District Attorney George Gascón said Wednesday that his office will dismiss and seal 3,038 misdemeanor convictions dating back before the state's legalization of marijuana went into effect, with no action necessary from those who were convicted.Prosecutors will also review up to 4,940 felony convictions and consider reducing them to misdemeanors.Petitioning to have a record expunged has been in place, but can be costly and it can require legal help, Gascón said in a statement. He said only 23 petitions were filed this past year in the city."A criminal conviction can be a barrier to employment, housing and other benefits, so instead of waiting for the community to take action, we're taking action for the community," he added.Gascón's office also noted racial discrepancies in marijuana arrests and sentencing. In 2000, African-Americans were 7.8 percent of San Francisco's population but comprised 41 percent of marijuana arrests. By 2010 and 2011, African-Americans made up about half of the marijuana-related arrests, yet represented only 6 percent of the city's population, according to the district attorney's office.In his statement, Gascón said San Francisco was "taking the lead to undo the damage that this country's disastrous, failed drug war has had on our nation and on communities of color in particular."Stores in California began selling recreational marijuana to adults legally at the beginning of this year after voters approved Proposition 64, in November 2016.Nine states and Washington, D.C. have legalized the recreational use of marijuana --and 29 states and D.C. have laws allowing "comprehensive" legal medical marijuana programs, according to the National Conference of State Legislatures.At least nine states also have laws "addressing expungement" of some types of marijuana convictions, the group says. Copyright 2018 NPR. To see more, visit https://www.npr.org/.