More than 1,800 prisoners are eligible for immediate release under new sentencing rules for drug crimes. The rules aim to reduce the disparity between sentences for crimes involving crack cocaine and those involving the drug in powdered form.

The New York Times reports tens of thousands of prisoners have received much tougher sentences for crimes involving crack cocaine than they would have received if the drug had been powdered cocaine.

Congress passed the Fair Sentencing Act of 2010 to address the disparity, and in June the United States Sentencing Commission voted to apply the law retroactively. The new policy went into effect this week.

The average crack cocaine sentence is 13 years, the article notes. Eventually about 12,000 inmates could have their sentences reduced by an average of three years.

Some critics say the releases will lead to more crime, while others say the new rules do not go far enough.