CALDWELL — The Noble Correctional Institution, a medium security state prison in Caldwell, is in the process of installing carbon monoxide detectors in all its residential buildings after an air quality problem in one of the dorms sickened 29 inmates and four staff members, a prison spokesman said.

A malfunction in one of the dorm air handling systems, assistant warden Joel Burris said, caused 29 inmates and four staff members to become ill from carbon monoxide exposure on Feb. 22.

“It created poor air quality in the unit, and the staff and inmates began showing signs of illness,” he said. “We evacuated the entire unit, checked everyone, and our medical unit sent anyone with symptoms to Southeastern Medical, and a few to Marietta Memorial.”

Nearly all were treated with oxygen and returned to the prison the same day, he said. One inmate remained hospitalized for a pre-existing medical issue that might have been aggravated by the carbon monoxide, he said.

“The Caldwell Fire Department checked the air quality and deemed it safe, and we moved the inmates back into the dorm,” Burris said. “We also had the other housing units checked. The fire department was in here all the following weekend, checking to make sure it was safe.”

Burris said that although the building codes do not require carbon monoxide detectors, as a result of the Feb. 22 problem the prison has installed detectors on both floors of the housing unit and is in the processing of similarly equipping all of the dorms.

“We’re in the process of buying them for all the units, taking a proactive approach to this,” he said.

Burris said independent contractors were also evaluating and reviewing the issue which caused the problem, which he said was related to a damper control in the central heating system. That problem was fixed, he said.

Carbon monoxide is an odorless, colorless gas generated by combustion. When inhaled it replaces oxygen normally transported by red blood cells and can result in tissue damage and death. Well-maintained home heating systems normally vent exhaust into outside air, but the use of grills and some other cooking and heating appliances can generate dangerous levels of carbon monoxide in unventilated areas.

Symptoms of carbon monoxide poisoning are headache, dizziness, shortness of breath and nausea. Minor episodes are usually treated with oxygen or just exposure to fresh air.

According to U.S. Centers for Disease Control and Prevention data, about 400 people a year in the U.S. die from carbon monoxide poisoning not directly related to fires. People who are drunk or sleeping are particularly at risk, as carbon monoxide exposure does not trigger a choking or coughing reflex – victims can die without waking up.

Public health agencies recommend that all dwelling places be equipped with carbon monoxide detectors. Residential detectors, which are usually battery-powered, cost between $20 and $50.

Amendments to the Ohio Fire Code that became effective in January specified that carbon monoxide detectors be installed in several categories of institutional buildings, but prisons and jails were not among those.

Despite that, the Washington County Jail is equipped with carbon monoxide detectors, Washington County Sheriff’s Office Chief Deputy Mark Warden said.

“There are detectors in the facility,” he said. “We have had no issues with them at all.”

The Noble Correctional Instutution in Caldwell is a medium security prison, opened 1996. Its staff of 396 people oversee 2,433 inmates, according to the Ohio Department of Rehabilitation and Correction.