STATEN ISLAND, N.Y. -- A 34-year-old woman arrested on drunken and impaired driving charges was found dead in a holding cell at the 120th Precinct stationhouse in St. George early Thursday morning, police said.

The woman -- whose identity has not yet been released pending family notification -- was found unconscious and unresponsive in the cell at around 4:35 a.m., and when EMS responded to the scene, she was pronounced deceased, according to a statement from the NYPD's Deputy Commissioner of Public Information.

The city medical examiner will determine the cause of death.

The woman had been arrested by Triborough Bridge and Tunnel Authority police officers when she was found passed out behind the wheel of her car at the Verrazano-Narrows Bridge toll plaza about 6 p.m. on Wednesday, an MTA spokesman said.

FDNY/EMS administered the Narcan anti-overdose spray, and the woman was transported to Staten Island University Hospital in Ocean Breeze for evaluation.

She was treated there and then transported to the 120th Precinct stationhouse for processing on charges of DWI and operating a motor vehicle while impaired by drugs, police said.

A hospital spokeswoman confirmed the woman was treated and released.

The investigation is ongoing.

More information will be posted when it's available.