NEW ROCHELLE, N.Y. (CBSNewYork)– A Westchester County family had gathered for a traditional Passover meal, but carbon monoxide was an uninvited guest and 15 people ended up in the hospital.

Four generations and one big family were all sound asleep following a late-night Passover celebration when they got an ominous 4:30 a.m. wake up call, CBS2’s Steve Langford reported.

“The alarm sounded, 24 of us sleeping in the house, because of the Passover holiday, we were all here,” Linda Eagle said.

What sparked the middle of the night alarm was not clear at first, but police and fire departments raced to the residence for a feared mass casualty incident.

“They got very lucky, they got very lucky that the alarm worked,” New Rochelle Fire Department Chief Robert Benz said.

A detector on the second floor of the home alerted the two dozen occupants to carbon monoxide.

“They said, ‘Get everybody out of bed ASAP, right away, get them into one room so we can test them,'” Eagle said said.

The source of the problem was a defective stove, officials said.

All inside were conscious, but 15 were rushed to the hospital, including several young children. Hours later, they returned home to a grateful family.

“The first night of Passover is Leil Shimrim, and that means the night of safety and security,” Eagle said. “As my niece said, it’s a Passover miracle.”

Dinner on the second night of Passover, without a stove, will be lukewarm, she said. But instead of an unspeakable tragedy that could have claimed an entire family, there is a very special reason to remember why this night is different from all others.