An inmate who took a prison worker hostage Wednesday released her unharmed and surrendered soon after, authorities said.

The female dental technician was held in a room at Waupun Correctional Institution for about five and a half hours, Department of Corrections spokeswoman Amy Reid said.

"Everything is OK," Reid.

She was taken hostage by a 38-year-old inmate who worked in the prison's Health and Segregation Complex, Warden Michael Thurmer said.

Prison officials learned of the situation about 6:30 a.m. The facility was placed on lockdown, and inmates were ordered to their cells. It remained on lockdown after the inmate surrendered.

The incident was limited to the room in the health complex, and there was no threat to the area surrounding the prison, Deputy Warden Michael Meisner said. No other prison employees were harmed during the incident.

Thurmer identified the inmate as Stuart Ellanson, who was convicted of murder in Douglas County in 1992. He arrived at the Waupun prison in 2004, he said.

Meisner said Ellanson did not threaten the dental technician. Thurman said he made general demands.

"One of his major demands was cigarettes," he said.

Ellanson had weapons that he gave up one-by-one as negotiations went on, Thurmer said.

Thurmer declined to give the dental technician's full name, saying he wanted to protect her and her family's privacy. She had a medical exam and was in "as good as spirits as can be expected," he said.

The maximum-security facility, a sprawling complex of brick and mortar with castle-like turrets, is the centerpiece of Waupun, a community of about 10,000 people about 70 miles northwest of Milwaukee.

The prison designed to hold 882 inmates now has 1,247 after the introduction of multiple bunking, state Department of Corrections spokesman John Dipko said.