Attorney General Eric Holder announced Friday that state and local officials would no longer be allowed to use federal law to seize private property such as cash or cars without evidence that a crime had occurred.

It’s the first major reform of a program launched as part of the so-called War on Drugs that has allowed police to confiscate billions of dollars in cash, vehicles and other types of property without evidence of wrongdoing. Since 2008, state and local agencies have seized $3 billion worth of property through more than 55,000 stops and seizures, and 80% of the proceeds go to local police departments or drug task forces, according to the Washington Post.

“With this new policy, effective immediately, the Justice Department is taking an important step to prohibit federal agency adoptions of state and local seizures, except for public safety reasons,” Attorney General Holder said in a statement. “This is the first step in a comprehensive review that we have launched of the federal asset forfeiture program.”

Federal asset forfeiture laws allow police to pull over motorists and seize property when there is suspicion of wrongdoing. Citizens must then prove that the property was legally acquired in order to get it back. That is often a costly and lengthy process; only one out of six seizures are legally challenged, according to the Post.

The unclaimed seized assets are then re-distributed among law enforcement agencies and the federal government. Between 2001 and 2014, state and local authorities have kept more than $1.7 billion through these kinds of seizures, while some $800 million has gone to the Justice Department, Homeland Security, and other federal agencies. Of those seizures, half were worth less than $8,800.

The new limitations announced Friday do not apply to property that could threaten public safety, like firearms, explosives, or child pornography.

For an in-depth explanation of the forfeiture program, check out the Washington Post’s investigation, which counted all the stops and seizures since 9/11 and traced how the money was used. For a more comic explanation, you can turn to John Oliver:

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Write to Charlotte Alter at charlotte.alter@time.com.