This March 23, 2011 photo shows the El Dorado Correctional Facility near El Dorado, Kan.

TOPEKA ? A staffing shortage constitutes an emergency at a Kansas maximum-security lockup that has seen several recent inmate disturbances, requiring mandatory overtime and shifts as long as 16 hours, the state’s prisons chief said.

Corrections Secretary Joe Norwood made that pronouncement in a letter Tuesday to an employee union in rejecting a grievance over long hours at the El Dorado Correctional Facility, The Wichita Eagle reported.

Mandatory overtime and extended hours are allowed in emergencies under the department’s agreement with the Kansas Organization of State Employees, the union that represents prison workers.

The prison moved to 12-hour shifts in June and the union later filed a grievance saying some workers were being required to work 16-hour shifts. Use of the 12-hour shifts will be reviewed every 90 days, according to Norwood’s letter, which insisted staffing levels were improving “with increased recruiting efforts and a reduction in the inmate population.”

The union’s director, Robert Choromanski, countered in an email that the department deliberately held off on declaring an emergency until Tuesday and was trying to “save face and embarrassment by forcing our hard working correctional officers under the radar into working these extra, unsafe and long hours.”

As of July 24, El Dorado had 80 open positions, down from 94 on July 5 after the department’s recruitment effort that included sending mailers to area homes.

The El Dorado lockup, about 30 miles east of Wichita, has had at least three inmate disturbances confirmed by the department since May 8, often involving groups of inmates who temporarily refused to return to their cells.