Students and staff were sickened by high levels of carbon dioxide at a school in Orange County.

The Washingtonville School District confirms “very concerning" levels of carbon dioxide were detected inside Little Britain Elementary School for weeks.

The levels were twice what's considered safe, according to Washingtonville Schools Superintendent Roy Reese.

Reese says the dangerously high levels of carbon dioxide were detected by air quality testing last month after children and staff reported feeling sick. 

A mother who didn’t want to appear on camera told News 12 that two kids in her child's classroom passed out from a lack of oxygen.

The district says windows are being kept open to provide fresh air while they try to determine the cause.

Parents say they are upset and that they weren't notified until a letter was sent out in mid-April.

District officials have apologized and say the entire building's air quality is now being tested.  They say that along with opening windows, fans have been provided to circulate air while classes remain in session.

Washingtonville officials say the issue is not with the heating system, which can lead to carbon monoxide poisoning. They are looking into the possibility that air isn't properly circulating inside the building and not allowing fresh air inside the building.