Two separate incidents of carbon monoxide leaks in a Missouri school and Pennsylvania day care are raising questions about whether state laws require carbon monoxide detectors in child care settings. But the answer is complicated, and at least 10 states don’t have any such laws.

Six students and two adults were taken to a local hospital Wednesday morning after falling ill at a Kansas City elementary school due to a carbon monoxide leak. The Kansas City Fire Department said it detected extremely high levels of the odorless, poisonous gas inside the building and evacuated the school.

Missouri is one of the states that do not require carbon monoxide detectors in schools or day cares.

In another incident, a Pennsylvania day care last week had a leak that sent at least 16 people to the hospital. Pennsylvania also does not have a law requiring a carbon monoxide detectors in day cares.

“The vast majority were improving as we saw them. But having said that, they were very sick,” Dr. Kenneth Katz, who treated the patients, told CBS News “Some of them had lost consciousness. One of the adults was complaining of chest pain.”

Nikki James Zellner, a Virginia Beach mother, said the Pennsylvania incident reminded her of when she learned that there was a carbon monoxide leak two years ago at the Virginia day care facility where her son, Owen, was being cared for. She said Owen was lethargic and confused.

“They had elevated levels [of carbon monoxide] in their bloodstream,” she told CBS News “They had irritability and behavior issues for about one to two weeks following.”

Zellner’s experience led her on a crusade to change the statute in Virginia, which paid off when the governor signed a bill last year requiring all public schools, including day cares, to have at least one carbon monoxide detector.

There is no federal law requiring the detectors in schools. CBS News learned that states with statutes requiring detectors often have a caveat with them — like only being required in buildings built after 2015 or in those with a carbon monoxide source like a gas furnace or boiler.

Zellner said she has received pushback to her efforts to get the detectors placed in schools. “The majority of the pushback that I would get was related to who’s going to pay for all of this,” she told CBS News. Industrial detectors can cost up to $240.

Dr. Katz added that a carbon monoxide detector is “a low cost device which unequivocally will save lives.”

Norah O’Donnell

Norah O’Donnell is the anchor and managing editor of the “CBS Evening News.” She also contributes to “60 Minutes.”