The violence over the past month led to one death last week at Menard Correctional Center, where the most recent assaults also happened. Union officials say the disturbances stem from Illinois Gov. Pat Quinn's decision to close several prisons around the state to save money, a move they claim has put staffers at overcrowded prisons at greater risk.
The assaults Tuesday occurred as about 200 union members marched outside the prison over what they say are growing threats to their safety. Menard is in the southern Illinois town of Chester, on the Mississippi River and about 70 miles south of St. Louis.
One inmate appeared to lure a guard into the attack inside the prison chapel, said Kevin Hirsch, a sergeant at the prison and president of Local 1175 of the American Federation of State, County and Municipal Employees. He said a chaplain and another guard who tried to help were hurt, too, and that 10 to 15 inmates were put in segregation after the incident.
"It was a very violent assault," Hirsch said. "A wave of inmates attacked them. ... These inmates planned to do some damage. They stomped these staff pretty bad."
The prison was locked down and the injured staff members were treated at a local hospital and released, Illinois Department of Corrections spokeswoman Stacey Solano said in an emailed statement. Solano didn't provide further details about the assault.
The first guard suffered the worst injury - a cut to the forehead that required stitches, said Henry Bayer, executive director of AFSCME Council 31, in an email.
Neither the Department of Corrections nor union officials would identify the staff members involved.
An inmate died last Thursday at Menard in what one official described as suspicious circumstances. On Jan. 28, a guard was attacked at the Pontiac Correctional Center in Pontiac in central Illinois and had to undergo facial reconstructive surgery as a result.
A guard also was injured Jan. 19 at Menard. And on Jan. 3, a guard was assaulted at Pinckneyville Correctional Center in Pinckneyville in southern Illinois.
A court gave Gov. Quinn the OK last month for a plan to close several prisons and other correctional facilities around the state to save money. Quinn started with the "supermax" prison in Tamms, some of whose inmates ended up in Pontiac.
AFSCME officials have complained that the governor's plan will place staff and inmates at other prisons that are overcrowded and at risk of violence.
"We are no longer talking about the threat of violence, but a rash of real and disturbing attacks by prison inmates on staff and others," Bayer said in his email. "The real-world consequences of Governor Quinn's reckless program of closures, layoffs and inmate transfers have arrived."
Solano defended Quinn's plan, citing cost savings and saying all prisoners from Tamms in southern Illinois were sent to what it called "appropriate maximum security facilities." She would not speak on the record about the number of inmates sent to Menard.
"The safety and security of staff and inmates remain the department's top priority," Solano said.
Quinn's office did not immediately respond to a request for comment.
The closing of the prison in Tamms eliminated space for 700 inmates, leaving the state's prison system with more than 49,000 inmates in space designed for 33,000.