A Pennsylvania day care likely did not have a carbon monoxide detector – nor was it required to – during a gas leak Tuesday that sickened more than two dozen children and adults, officials said.

Allentown Mayor Matt Tuerk told reporters Tuesday afternoon that he was under the impression that Happy Smiles Learning Center did not have carbon monoxide monitors, though the fire marshal was still investigating.

Tuerk said all those effected during the gas leak are in stable condition. In all, 28 children and four adults were rushed to four nearby hospitals Tuesday morning, according to WFMZ-TV.

"Due to the quick action of our first responders, we were able to avoid tragedy in Allentown today," the mayor said. 

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Tuerk also said that the Pennsylvania state legislature did not pass an ordinance that would require commercial day care centers to have the life-saving monitors installed.

ambulance and fire trucks outside daycare

All of the ambulances in Allentown, Pennsylvania, reportedly responded to the incident. (FOX29 Philadelphia WTFX)

However, the city council had taken action to pass a local ordinance to require carbon monoxide monitors effective Oct. 27, the mayor said.

The day care center was inspected in August, according to Tuerk, but officials were not looking for carbon monoxide monitors because they were not required at the time, and the facility passed.

first responders outside daycare

Multiple children were sickened after carbon monoxide leaked in a daycare in Allentown, Pennsylvania. (FOX29 Philadelphia WTFX)

Tuerk said residents need to call on state legislators to pass the ordinance requiring carbon monoxide monitors statewide.

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The day care remains closed pending inspections, and would be required to have carbon monoxide monitors upon reopening.

The incident remains under investigation.