MADISON, Wis. (AP) -- The head of the state employees union tells an Assembly Committee that safety at Wisconsin's prisons has deteriorated since workers there lost their ability to collective bargain.

Marty Beil told the committee Wednesday that staffing shortages have also led to increased stress on workers who are there and created an unsafe environment. He says six workers have been assaulted by inmates since Christmas Eve.

But Corrections Secretary Ed Wall says none of the people in any of those incidents were admitted to the hospital. He says he couldn't discuss them in more detail because of health privacy laws.

Beil says the Wisconsin State Employees Union represents about 1,800 Corrections workers. Prison guards have been organizing an effort to separate from the WSEU and form their own union.