(UPDATED 9:15 AM THURSDAY) WILLIAMSON COUNTY — The Williamson County Sheriff’s Office says the source of Wednesday’s carbon monoxide leak at the Williamson County Jail has been found.

Sheriff Bennie Vick says contractors and engineers are confident that the carbon monoxide came from a boiler that malfunctioned overnight. That boiler will remain shut down until all repairs have been completed and the system passes all tests.

All inmates who may have been in the affected area of the jail have been evaluated. As of yesterday, 15 inmates had been treated and released from local hospitals.  Correctional staff that were affected by the leak either have been or will be assessed. All staff members who were assessed were released yesterday.

The Marion Fire Department and Ameren checked the building and told the sheriff’s office normal operations could resume.

The sheriff thanks Heartland Regional Medical Center and Herrin Hospital along with the Marion Fire Department, Johnston City Fire Department, Abbott Ambulance Service, and Ameren for their help with this incident.

(ORIGINAL) WILLIAMSON COUNTY — There was a carbon monoxide issue early Wednesday morning at the Williamson County Jail in Marion.

Williamson County Sheriff Bennie Vick says at about 4 a.m., an inmate contacted corrections staff with complaints of a headache.  After an initial assessment, the decision was made to transport the inmate to an area hospital for a more thorough assessment and treatment. After the inmate as treated at the hospital, the inmate was cleared to return to the jail.

As this morning progressed, additional inmates and staff began to complain of headaches or dizziness. The Marion Fire Department was contacted and asked to conduct air quality tests. These tests determined that there was carbon monoxide in part of the jail.

Additional tests determined that only a small part of the jail was affected. Inmates and staff were moved from the affected area into areas that were not affected. Medical assessments were conducted, and a small number of inmates and staff were transported to area hospitals as a precaution.

The Marion Fire Department and other fire departments have been on scene to ventilate the building. Ameren and engineers are also on scene to determine the source of the carbon monoxide.

Visitation at the jail is cancelled until further notice.

Court cases for inmates have also been affected and will have to be rescheduled.

Additional information will be released as it becomes available.