Seven people were taken to the hospital after a broken vent pipe on a water heater filled a Valley Stream home with carbon monoxide.

The Nassau County Fire Marshal's office said investigators do not believe there were any operating carbon monoxide detectors, though that's still under investigation. Personal detectors carried by police medics on the scene immediately detected the dangerously high levels of the gas.

Nassau County police said first responders went to 15 Henrietta St. just before 9 p.m. Sunday for a report of an unresponsive female.

Inside the home, police found two women on the first floor, ages 22 and 47.

Both are still in critical condition, the Valley Stream Fire Department said this afternoon.

Five more people inside the home, ages 2, 10, 22, 28 and 30, were also exposed to carbon monoxide.

All seven people were taken to Nassau University Medical Center.

Investigators also said the home was illegally subdivided with multiple single-room occupancies.

Carbon monoxide is a colorless, odorless and tasteless, poisonous gas that reduces the availability of oxygen in the blood and can cause death by asphyxiation.

The incident happened the same day we moved our clocks forward an hour for Daylight Saving Time. This is the time firefighters and other emergency responders generally recommend that you replace the batteries and test all home smoke and carbon monoxide detectors.