BOSTON -- Fire chiefs renewed warnings Tuesday that students across the state face risks of carbon monoxide poisoning because of a gap in regulations that effectively allows many older school buildings not to install detectors.

Any new school constructed with state funds must include carbon monoxide monitoring technology, but that mandate does not apply to existing structures because students do not stay overnight. Several bills before the Joint Committee on Education would amend those rules and require every district to ensure detectors are present in every building, something public safety officials called a necessary step.

"No parent would expect their child to go to school without a fire alarm," said Douglas Fire Chief Kent Vinson. "That's an enemy we can see. We can see fire, we can see smoke. Carbon monoxide is odorless and tasteless. It'll take you before you even realize."

Bill Scoble, government affairs director for the Fire Chiefs Association of Massachusetts, said he believes many pre-existing school buildings across the state still lack carbon monoxide alarms, although he said providing an exact number would be challenging.

Firefighters respond to about 40 carbon monoxide calls at schools across the state every year, according to Scoble. In Boston, he said, just two of 122 school buildings currently have detectors installed. The district's press office could not be reached to confirm that figure Tuesday afternoon.

"There's very few (districts) that just went out and did it on their own," Scoble told the News Service. "You've got this wide range in capabilities of alarm systems, some that can take, some that can not. But unless there's a requirement to do it, unless there's a requirement in the city or town, this is something that has not been addressed."

Similar legislation has stalled on Beacon Hill in the past, even after the Senate approved a bill requiring carbon monoxide alarms in schools and restaurants in 2014. This is the first session that it is before the Joint Committee on Education.

In 2014, 16 Douglas students and two adults were hospitalized for carbon monoxide poisoning, and while that community installed alarms in its schools, the Legislature has yet to expand the requirement to older buildings as Vinson requested.

"We dodged a bullet, but that's why I have such a passion for making this happen," he said Tuesday. "We don't want to see someone die because we failed to act."

Two of the bills (H 399 and H 412) before the Education Committee would go beyond schools and implement mandates for many other public structures to use carbon monoxide detectors. A bill known as "Nicole's Law" and approved in 2005 requires most homes to install the alarms.

The latter of those bills is something that Rep. Paul Brodeur has now filed in four different sessions without seeing it cross the finish line. His bill would create a $7.5 million trust fund to help defray the costs of installing detectors.

"There is an expectation, an assumption, that this kind of equipment is already there and that schools across the board are well-equipped to handle this," Brodeur said. "That's just not the case."