NEW YORK — After Superstorm Sandy hit the East Coast nearly two years ago, the federal government quickly sent out $1.4 billion in emergency disaster aid to the hurricane’s victims.

Now, thousands of people might have to pay back their share.

The Federal Emergency Management Agency is scrutinizing about 4,500 households that it suspects received improper payments after the storm, according to program officials and data obtained by The Associated Press through a public records request. As of early September, FEMA had asked around 850 of those households to return a collective $5.8 million. The other cases were still under review.

FEMA’s campaign to recover overpayments, called “recoupment” in agency lingo, typically involves instances where the agency believes a household got more money than allowed under program rules, but not necessarily because of an intentional attempt to cheat the system. Fraud cases are handled separately.

Many people asked to return money were deemed ineligible because their damaged properties were vacation houses or rental properties, not their primary residences. Others had double dipped into the aid pool, with more than one household member getting payments. Some received FEMA money for things later covered by insurance.

As of July 30, the average demanded refund was $6,987, a sum that could be difficult for many, given the modest annual incomes of most aid applicants. Roughly half of the households under scrutiny reported an annual gross income of $30,000 or less.

The larger pool of cases still under review as of that date involved $53 million in aid payments — or about 3.7 percent of the total given out by FEMA through its individuals and households program — though any potential refunds would likely involve only a portion of that money.

“For most people, the money is long gone and long ago spent on storm recovery,” said Ann Dibble, director of the New York Legal Assistance Group’s storm response unit, which has been helping about a dozen families fight a FEMA clawback.