A state lawmaker proposed Friday that carbon monoxide detectors be installed in Georgia schools by July 1.

Rep. Sheila Jones, D-Atlanta, filed the legislation four days after lethal levels of the gas were found in an Atlanta elementary school, where more than 40 children and some adults were sent to hospitals.

The state education department is also urging Georgia school officials to evaluate the potential threat posed by carbon monoxide.

Georgia law does not require carbon monoxide detectors in schools, but some districts are moving ahead anyway with plans to add them.

In Macon, for instance, detectors will be installed in more than 22 schools in the 24,000-student Bibb County school system, one of Georgia's largest.

After the Atlanta leak, Bibb County crews identified 22 of the district's 41 schools that had boiler rooms inside the building, and those will get new $95 units that detect carbon monoxide, said David Gowan, the system's director of risk management.

"They are going to be tied into our fire alarm system, which means that if we had an accidental release, the fire detectors will go off," Gowan said. That will lead to loud, flashing alarms throughout the building.

Only 22 schools are getting the detectors, scheduled to arrive next week, because the system's other schools have different heating systems - such as boiler units on school rooftops or units powered by electricity, Gowan said.

In Gainesville, schools will have battery-operated detectors installed in all city schools - older buildings and newer ones, said Keith Vincent, maintenance and operations director for Gainesville City Schools.

Whether to add carbon monoxide detectors to schools depends on the design of the building, the heating system and other factors, said Mike Larranaga, a professor and department head at Oklahoma State University's School of Fire Protection and Safety.

All buildings with a combustion appliance inside should have a carbon monoxide detection system in place, in Larranaga's view.

Combustion appliances burn fuels for heating, cooking or other uses and would include stoves and furnaces, according to the National Safety Council.

"Any gas-fired appliance has the potential to cause carbon monoxide poisoning," Larranaga said.

Schools wouldn't need detectors in every room because carbon monoxide travels and fills spaces, he said.

Placing detectors in older schools with boiler units isn't enough, he said. They might be even more important for new buildings designed to be environmentally friendly because some of them hold carbon monoxide gas inside longer. In newer building designs, there's less air exchange between the inside and the outdoors, he said.

Though detectors can be life-savers at night, when people are sleeping, the gas is colorless and odorless and children are more at risk, Larranaga said.

"With children, they're even more susceptible to carbon monoxide than adults because they have higher respiration rates, a higher metabolism," he said.

In a memo sent to school systems across the state this week, the Georgia Department of Education encouraged officials to evaluate potential exposure to carbon monoxide in schools.

The state education department has heard from some school officials since the Atlanta leak.

"Many of them have a newer system that doesn't even have the boiler," said Matt Cardoza, a spokesman for the agency.