It is a hospital's nightmare: The power goes out and backup generators don't kick in, leaving critically ill patients without the mechanical help they need to breathe.
It happened in New Orleans after Hurricane Katrina, when hospital staff were on their own when electricity and water cut out. Some died.
It happened last year in San Diego, when generators at two hospitals failed during a blackout.
And it happened last year in Connecticut, when a hospital had to be evacuated during Hurricane Irene when its generator failed.
As Hurricane Sandy headed toward the East Coast, New York City Mayor Mike Bloomberg said Sunday, he was assured that hospitals were ready. "The teams from the City Health Department are at these facilities making sure that the emergency generators are working and that they have back-up fuel supplies," he said at a news conference before the storm.
In spite of this confidence, the generators at some hospitals did not work as expected.