By the time the school bell rang at Finch Elementary School, the building in southwest Atlanta had carbon monoxide levels few firefighters had ever seen.

“Some of the levels we got were extremely high,” said Atlanta Fire Battalion Chief Todd Edwards. Carbon monoxide “can kill you in a minute.”

Firefighters think the school’s heating system went bad sometime over the weekend. So the colorless, odorless gas had been building up for days, waiting for students to arrive.

The highest readings reached 1,700 parts per million. Health officials say people should limit their exposure to 50 parts per million over an eight-hour period. Those levels are high enough for a person to pass out in seconds.

And at Finch, they were.

"My teacher was talking about the projects then we passed out," said 7-year-old student Jacobi Lyons.

By 8:30 a.m. Monday, so many students and teachers were getting sick, Principal Carol Evans called for emergency personnel, who began evacuating the school of its 500 students.

Georgia school administrators say they can’t remember anything like this happening in 30 years.

Which might be why carbon monoxide detectors are not required in Georgia schools are any state buildings.

Finch Elementary did not have any. But that will probably change.

“They are relatively inexpensive items,” Atlanta Public Schools Superintendent Erroll Davis said during a press conference Monday. “Depending upon how many we decide to put in at each school, I don’t see this as being a tremendously large expense.”

Normal home carbon monoxide detectors cost about $20.

The emergency in Atlanta has also gotten the attention of lawmakers across the state, who were not aware that carbon monoxide detectors are not required

"No cost is too much when it comes to saving lives," said State Sen. Gloria Butler, D- DeKalb/Gwinnett counties.

Even the state Insurance and Safety Fire Commissioner was in the dark.

"I found out they're not required," Hudgens told Channel 2 Action News. "I guess you could say we're not very smart if we don't learn from our mistakes and this definitely (is) something, something is wrong,"

Hudgens says the Georgia legislature will take a hard look at whether state law should require carbon monoxide detectors in schools as well as nursing homes and possibly other commercial buildings.

Of the 50 people that were taken to the hospital, one adult was being at Grady for observation while another person was sent to another hospital for hyperbaric treatment.

Finch will be closed Tuesday. Classes will be held at Kennedy Elementary school, APS spokesman Stephen Alford said.

Meanwhile, state inspectors will be going over every inch of the school’s 8-year-old boiler system.

"We have to look at exactly what happened to this boiler. If it's something that's very unique, might be something before or after the boiler as well," Davis said.

By law, boilers in schools must be inspected every two years. In November 2011, Finch’s passed and showed “no adverse conditions,” the inspector wrote in the report.

Inspectors think a valve may have gone bad.