Inmate riot at prison near Folsom that sent four to hospital under investigation

California prison officials are investigating a riot involving about 20 inmates that broke out Monday morning at California State Prison, Sacramento, near Folsom, leaving several men injured.

The California Department of Corrections and Rehabilitation said the disturbance began around 10 a.m. Staff at the prison — also known as New Folsom — responded with chemical agents, warning shots and nonlethal weapons to regain control.

“Four incarcerated individuals sustained injuries requiring transfer to outside medical facilities for further treatment,” CDCR officials said Tuesday. “The individuals’ injuries are reported to be non-life threatening at this time.”

No staff members were injured, CDCR said.

Officials said four improvised weapons were recovered from the scene.

The inmates involved have been placed in restricted housing pending investigation, and movement within the prison remains limited, authorities said.

The incident came days after two correctional officers were injured in a separate assault at the facility.

On Nov. 1, a 48-year-old inmate allegedly attacked the officers with an improvised weapon during a cell search around 7 p.m., CDCR said. Both officers were hospitalized following the incident.

“The safety and security of staff, incarcerated individuals, and the institution remain our highest priority,” CDCR said.

It was unclear what prompted Monday’s riot or whether those involved were affiliated with gangs.