Some PSEG Long Island customers are receiving fake emails appearing to be billing statements and asking for personal information.
Warning about the possibility of identity theft, the utility said it would not ask its customers to provide personal information online without first having them set up a bill-pay account.
Customers who receive suspicious emails should delete them and notify the utility at 800-490-0025.
"We take very seriously any attempt to defraud our customers," said Dan Eichhorn, PSEG Long Island vice president/customer services.
Concerned customers also can visit one of the utility's Customer Service Centers, open from 8:30 a.m. to 5 p.m., Mondays through Fridays.
Locations are listed on customer bills and online, the utility said.