The Rev. Al Sharpton praised an announcement Friday by U.S. Attorney General Merrick Garland that revealed he’s scrapping a decades-long federal policy that has treated crack cocaine offenders more harshly than powder cocaine offenders.

“This was not only a major prosecutorial and sentencing decision, it is a major civil rights decision,” Sharpton said in a statement.

Garland instructed federal prosecutors to stop relying on the weight, charging and sentencing guidelines long used in prosecuting crack cocaine cases, and to apply the less-onerous guidelines for powder cocaine, under certain circumstances.

Outlined in a memorandum first reported by The Washington Post, the move amounts to a prosecutorial or administrative fix for disparities that have persisted since the mid-1980s, notwithstanding a partial rollback by Congress in 2010. Garland aides told the Post the new guidelines take effect within 30 days.

Under current federal law, possession of as little as 28 grams of crack cocaine triggers a five-year mandatory sentence, while possession of 500 grams of powder cocaine triggers the same mandatory sentence – a nearly 18-to-1 ratio. The ratio was 100-to-1 under the 1986 crime bill pushed through Congress by then-Sen. Joe Biden of Delaware, amid what was variously described as the “war on drugs” and the “crack epidemic.”

“The Justice Department supports elimination of the crack-to-powder sentencing disparity and has testified before Congress in support of the EQUAL Act, S. 79, which would remove that disparity,” Garland’s memorandum states.

“As the Department has explained: ‘First, the crack/powder disparity is simply not supported by science, as there are no significant pharmacological differences between the drugs: they are two forms of the same drug, with powder readily convertible into crack cocaine.’”

Sharpton and other activists have long decried the different treatment, and how the drug laws have been applied. A variety of surveys have shown low-income Black crack offenders being imprisoned at much higher rates than other racial groups, and receiving longer sentences as well, fueling a mass incarceration that has taken generations of Black men off the streets.

Over the decades, Sharpton led marches against the federal “war on drugs” and New York’s tough Rockefeller Drug Laws. He said the federal measures “have ruined homes and futures for over a generation.”

Anthony Romero, executive director of the ACLU, lauded Garland for moving to end a “decades-long, unjustifiable, and racist policy.”

“For 36 years," Romero said in a statement, "the sentencing disparity between crack and powder cocaine has fueled mass incarceration and devastated communities of color and Black families in particular, while failing to provide any public safety or public health benefit.”