Nearly 800,000 can clear records for pot possession. Here's how.

A new Illinois law effective Jan. 1 makes it legal to possess 30 grams or less of marijuana for recreational purposes. Getty Images

SPRINGFIELD -- For decades, getting caught with a small amount of marijuana could put Illinois residents in jail for up to six months and perhaps worse. The criminal record would follow them for the rest of their lives.

Gov. J.B. Pritzker's signature this week on a law legalizing recreational cannabis includes a provision for nearly 800,000 people to clear their records.

Lawmakers who drafted the measure legalizing marijuana emphasized repairing what they say is the damage done by the war on drugs. They say it particularly affected minorities, who were likely to be arrested and prosecuted for marijuana offenses. Expungement of criminal records is a key part of that.

What is expungement?

Expungement is a process under which a judge seals a criminal record from view. But it's complex and often requires spending thousands of dollars for a lawyer.

The new Illinois law drops the ban on possessing 30 grams (one ounce) or less of marijuana.

So supporters are pursuing expungement for those who were arrested or convicted of that when it was a crime.

This is because such records show up in criminal background checks and can cost someone a job or housing.

Offenders are "forced to live in permanent second-class citizenship ... and forced to face those collateral consequences everywhere," said Rep. Jehan Gordon-Booth, a Peoria Democrat who led the expungement push.

Illinois officials estimate there are 770,000 marijuana-related criminal records eligible for expungement.

Do other states expunge pot records?

Yes, but Illinois' law allows for near-automatic expungement of marijuana arrest or conviction records as long as there are no violent crimes associated with them. There's even a streamlined method for scrubbing records involving the manufacture, possession or delivery of 30 to 500 grams (1.1 pounds), even though it remains illegal.

How does it work?

In the case of arrests for possession of 30 grams or less, the Illinois State Police and local police agencies have six months to find those records and destroy them.

For convictions, state and local police must forward those records within six months to the Prisoner Review Board. The board will review each case for eligibility -- essentially ensuring it's the right person, the record is correct, and no violence was involved. Cleared records then go to the governor for pardons, clearing the way for an expungement.

This means that the governor is likely to issue hundreds of thousands of pardons.

But Pritzker's deputy governor, Christian Mitchell, noted that the process is much more streamlined than the standard clemency process.

The governor's staff will simply be ensuring that the Prisoner Review Board properly reviewed each record.

The attorney general, representing the Prisoner Review Board, then goes before a judge to seek an expungement.

Finally, for cases involving 30 to 500 grams, the person with the record must ask a judge to vacate the conviction and expunge the record.

The judge will consider police agencies' objections, the person's age at the time of the offense and current age and any "adverse consequences" that would accompany denial of the request.

Rep. Kelly Cassidy, a Chicago Democrat and lead sponsor of the legislation, said it's a much less complicated method than previously existed and the law provides money to legal aid organizations that provide attorneys to represent people who can't afford them.

Can prosecutors object?

State's attorneys may file objections, but in limited ways. For example, if the case is a conviction for 30 grams or less, the local prosecutor may object only to whether the person named in the record is correct.

But Democratic Cook County State's Attorney Kim Foxx actively pursued the expungement provision because it was "prosecutors who implemented these convictions."

"It was my obligation to have a seat at the table and make sure that the work that my office and offices like mine across the state have done to inflict harm, that we're there to repair the harm that we caused," Foxx said.

Why streamline expungement for things that are still illegal?

The manufacture, possession or delivery of 30 to 500 grams of cannabis in Illinois remains a crime.

But an easier path to expungement for past offenses makes sense in a state that has now created an industry in which authorized dealers will handle tons of the product, Mitchell said.

"For them (past offenders) to have to deal with the collateral consequences while wealthy businessmen get to do it scot free because it's legal now, there's a moral bankruptcy there," Mitchell said.