By DOUGLAS MONTERO
May 7, 2007 -- It's a pervert's dream come true.
Hundreds of city elementary-school kids are sitting ducks at public libraries where they hang out alone, unsupervised and vulnerable, because their parents can't afford after-school baby sitters or don't want to deal with their own kids.
The crisis has turned libraries into impromptu day-care centers and good-hearted librarians into unofficial baby sitters for children who have nowhere to go between 3 and 6 p.m.
"It's a growing problem throughout the state," said Michael Borges, the executive director of the New York Library Association. "It's unfortunate that parents are so desperate that they have to use a library as a baby-sitting service."
Fed-up librarians say the overlooked problem is a tragedy waiting to happen.
"I do the best I can, but sometimes, there are just too many for me to watch," an East Harlem librarian said. "One day, a kid disappeared for five hours, and the mother got in my face and threatened to sue me because I wasn't watching her daughter."
A Brooklyn librarian said she's even called the cops because unattended kids were left behind after the library closed.
The standard rule across the state is that children under 14 are prohibited from hanging out in a library without an adult, Borges said. But that didn't stop a rambunctious first-grader from recently being left alone in the East 110th Street library branch for two hours to do his math and English homework.
A 10-year-old said he spends about 90 minutes in the same library until "I get the call from my father when he's ready to pick me up."
"My mom is at work, so she can't pick me up," the boy said.
Margaret Tice, the New York system's coordinator of children services, said only, "The library staff makes sure the library is safe for all of our patrons."
Jason Carey, a spokesman for the Brooklyn Public Library, said unattended children are handled on a "case-by-case basis," adding, "I don't think we have a noticeable problem."
Tasha Salomon, 36, takes her kids to the Crown Heights branch, which is "swarming" with unattended kids.
"It's scary because you don't know what's going to happen, especially when you hear about all these kids being snatched," she said.
In March, one fed-up parent called the cops on a Bronx mom who chronically ditched her three kids, including one in a carriage, at the Morris Park branch.