A federal judge who sentenced a Dorchester man to life in prison in 2006 under a law passed during the Reagan era this week reduced his sentence to 216 months, which means he could be freed later this year, about 16 years after he was first put behind bars following his arrest.

At the time, federal law required that the equation used to determine sentences for crack possession be weighted 100 times that of cocaine-powder possession. Following Earl Dickerson's conviction on possession of nearly 58 grams of crack with intent to distribute and possession of another 11 grams of crack and for being a felon in possession of a firearm, US District Court Judge Rya Zobel had no choice but to impose a mandatory life sentence.

But in 2010, Congress passed a law that dramatically reduced the crack enhancement in the sentencing guidelines used by federal judges. In 2018, Congress passed a law making the new calculations retroactive to people convicted under the Reagan-era law.

Dickerson, who was arrested March 9, 2014 in his apartment on Westcott Street in Dorchester, had lost previous appeals for a sentence reduction, appealed under the new laws.

Even federal prosecutors agreed he should have his sentence reduced - although in a memorandum to Zobel, the US Attorney's office in Boston said he should still spend another 13 years in prison. Prosecutors said that even without the mandatory life requirement at the time, Dickerson would have faced a sentence of between 40 years and life "based on his designation as a career offender and an armed career criminal, as well as his extensive criminal history" - which included four state cocaine-distribution convictions in the 1990s.

Dickerson's attorney argued he should be released immediately, that 16 years locked up was enough punishment and that Dickerson, now 46, is a changed man - he realizes he did wrong and that he wants to settle down and care for his children and grandchildren.

"Mr. Dickerson realizes the high cost of his past mistakes. His focus now is on his family, and on his successful reintegration into society. His family has offered him a residence in Wilbraham, owned and occupied by the father of Mr. Dickerson's niece, and the U.S. Probation Department has approved the residence."

Zobel, who had held numerous hearings on Dickerson's case between his sentencing and her ruling Tuesday, ordered that in addition to having his sentence reduced, Dickerson undergo drug treatment and testing and mental-health counseling and that he receive "life and vocational skills" training somewhere closer to Massachusetts than Pollock, LA, where he is currently an inmate at a high-security prison. She also ordered him to eight years of probation.