Bellevue Hospital is being evacuated after officials say equipment and a laboratory was too heavily damaged by flooding after Sandy.
Mayor Bloomberg said in a press conference Wednesday hospital officials initially believed they could sustain operations using a backup generator, but found the water damage in the basement was too significant.
Crews are having to clean up after 17 million gallons of water poured in, Bloomberg said.
About 725 patients were affected, according to officials. The FDNY and the National Guard were assisting in transferring the patients, who were all expected to be in other hospitals by Thursday.
Bellevue overlooks the East River on First Avenue, which saw heavy flooding during Sandy.
The NYU Langone Medical Center evacuated 300 patients Monday night after it lost generator power due to the storm.