A 13-year-old girl has died and over 20 more people were sickened in an apparent carbon monoxide poisoning incident in Perth Amboy.

City officials say that several people are in critical condition following the leak. Many more, including some police officers and firefighters, were treated for carbon monoxide exposure.

The incident happened Thursday afternoon at an apartment building located at 185 Fayette St.

The building was evacuated, and residents were taken to a nearby warming shelter due to the frigid temperatures.

Officials say that they have not yet found the source of the carbon monoxide leak. They will go through every appliance inside the building to make sure that it is safe to be inhabited, they say. The building is being ventilated to clear out the fumes.