Long Island Power Authority Board Chairman Howard Steinberg quit under fire yesterday — becoming the latest in a string of departures due to criticism of LIPA’s performance in the wake of Superstorm Sandy.

In a letter to Gov. Cuomo, Steinberg, who was appointed by Gov. George Pataki in 1999, said his work as a private-sector attorney precluded him from devoting the time needed to face LIPA’s myriad challenges.

His resignation follows those of LIPA Chief Operating Officer Michael Hervey, trustee X. Christofer Damianos and Vice President of Customer Service Bruce Germano.

The utility is being investigated for its post-Sandy performance. More than 1 million customers lost power, and many remained in the dark for more than two weeks.