Topeka ? Illegal sex is a problem in Kansas prisons, but it’s not as widespread as inmates and staff suggest, the state’s top prisons official said Monday.

Corrections Secretary Roger Werholtz responded to an investigation by the Topeka Capital-Journal, which reviewed hundreds of documents on the Topeka Correctional Facility and interviewed inmates and prison employees. The investigation concluded as many as a third of the prison’s 250 staff members have been involved in an illegal black market, including exchanging sex with female inmates for drugs.

Corrections Department officials have said a more realistic estimate is 2 percent of the 3,000 employees at the state’s eight prisons, and Werholtz agreed with that. But he said even one case was too many.

“The reporting that has been done doesn’t rise to the level that is being portrayed, but I don’t want to minimize that even one instance is OK, because it’s not,” he said. “If we have evidence, we will refer the case for prosecution.”

In September, the U.S. Department of Justice inspector general reported sexual abuse of inmates by workers in U.S. federal prisons had doubled in the previous eight years. The report found 257 cases were uncovered and referred for prosecution, but only 102 were prosecuted. The cases resulted in 83 convictions against prison employees.

One Kansas case included in the federal report involves former vocational plumbing instructor Anastacio “Ted” Gallardo, who admitted in court that he brought tobacco and drugs to prisoners at the Topeka facility and had sex with at least one inmate. He pleaded guilty to the crimes and was placed on two years’ probation. An order to register as a sex offender has been stayed pending appeal.

Kansas allows inmates to report abuses anonymously in surveys done every 120 days. That’s how Gallardo’s crimes were discovered.

Gov. Mark Parkinson said in a statement Monday he was confident in the Kansas prison system’s procedures, but he also takes the concerns from staff and inmates seriously.

“Nobody should be abused or exploited,” Parkinson said. “There are always ways to improve, and I will be working with the Department of Corrections to identify ways to further minimize misconduct in our corrections system.”