California is moving to end the practice of allowing private companies to capitalize on mass incarceration.

Gov. Gavin Newsom signed a bill into law Friday that bans private, for-profit prisons and immigrant detention centers in the state. The decision comes amid growing consensus around the need to end private incarceration in the U.S.

“It's really important to pass this bill because it protects the health, safety and welfare of Californians,” says Rob Bonta, the California assemblyman who wrote the bill. “And we know from study after study that in for-profit private prisons and detention centers, Californians are getting hurt.”

Several Democratic presidential candidates have also responded to calls to close private prisons, which federal and state governments grew to rely on as a result of tough-on-crime initiatives in the 1980s and 1990s, according to The Sentencing Project. Today, 8% of people imprisoned in the U.S. are housed in private prisons, though 21 states don’t house any inmates in private prisons.

The California bill will move to close three privately run prisons in the state, which house nearly 1,400 inmates, when their contracts with the state expire in four years, according to Reuters.

“[Private prison companies] are chasing the almighty dollar,” Bonta says. “They're not investing in the Californians in their detention centers. In fact, they're doing the opposite. They're divesting.”

Bonta and other supporters of the bill say that for-profit prisons are only looking to maximize profits at the expense of inmate safety.

“The data is indisputable,” Bonta says. “It shows that they have less access to health care, higher levels of escape, higher levels of recidivism, lower staffing, less training for staff, higher numbers of assaults on staff. People have died in these facilities.”

The private prisons that would be impacted are run by GEO Group and CoreCivic, two of the largest private prison companies in the country. The companies say private prisons are necessary in order to house a ballooning number of inmates.

But Bonta says that California is prepared to house all of its inmates without private prisons. In fact, following decades of growth, the percentage of people in American prisons is the lowest it's been in 20 years. The decline is in part due to criminal justice reform measures at the federal and state level, Bonta says.

California will also not renew its contract with private detention centers that hold immigrants. This amounts to four private facilities that hold nearly 4,000 detainees.

Critics say that after closing the California detention centers, U.S. Immigrations and Customs Enforcement will simply move those inmates to other facilities out of state. Bonta says that’s just one possibility.

“With less capacity, maybe they detain less individuals and decide they don't need to do it,” he says. “Maybe they build their own facilities in California and also maybe they do move individuals out of state, and that's why I think it's important that other states act as California has acted.”

Francesca Paris produced and edited this interview for broadcast with Todd Mundt. Samantha Raphelson adapted it for the web.