Toms River Police say Officers Brian Jackowski, 39, Chelsea Richard, 26 and Daniel Reale, 19, were hurt Friday morning.
It happened around 9:00 a.m. near Boulevard and N streets.
Witnesses say an estimated five or six officers were riding on the back of a truck headed back to the police station.
Authorities say a bench in the back snapped off, causing several officers to fall out.
"Evidently there was a malfunction with one of our high water vehicles, and the officers fell out of the vehicle onto the roadway," said Chief Francis Larkin, Seaside Park Police Department.
The injured officers, two male and one female, all suffered head injuries.
Medics worked on one of the officers inside a State Police helicopter moments before another victim was loaded inside.
Shortly after the chopper took off, another landed.
Chief Larkin says all three were conscious and talking at the time of transport.
They were taken to Jersey Shore Medical Center.
Officer Richard was hurt most seriously. She is hospitalized in critical condition. Officer Reale is hospitalized in serious condition. Officer Jackowski was treated and released from the hospital by Friday afternoon.
Seaside Park resident Robert Rochford walked up after the accident. Only minutes before he saw the same group drive by.
"That truck was turning around from the saw mill, had all officers on it, I saw the Seaside Park logos, they honked the horn and waved," said Rochford.
"There was a lot of chaos, and ambulance - it was just a mess," said Danielle Dinapoli.
Officials from Toms River are handling the investigation of the accident.