(CNN) -- Inmates at California's San Quentin prison helped rescue two boaters -- one of whom later died -- who had fallen into frigid San Francisco Bay early Wednesday, authorities said.
A San Quentin officer alerted the prison's inmate-staffed, in-house fire department around 1 a.m. after hearing faint calls for help and seeing a man and a woman in the water near the facility's shoreline, prison spokesman Lt. Sam Robinson said.
Prison staffers and 10 fire department inmates went into the water and grabbed the man, who was without a life jacket, and lifted him over a retaining wall to get him on land, Robinson said. San Rafael Fire Department personnel arrived and helped rescue the woman, who was wearing a life jacket.
The man, who was breathing but apparently unconscious when he was rescued, went into cardiac arrest on shore, Robinson said.
"A staff member and inmates then began CPR and other life-saving measures" until an ambulance took him to a hospital, Robinson said.
The man, James Laurel, 44, of Larkspur, was pronounced dead at Marin General Hospital, Marin County sheriff's Lt. Barry Heying said in a press release. The woman, whose name wasn't announced, was treated at a hospital for exposure and released, according to the sheriff's office.
Deputies determined that the pair had been in a small boat, leaving a dock on Corte Madera Creek at about 10 p.m. Tuesday, the sheriff's office said.
The boat had engine trouble in the bay, and Laurel fell overboard while trying to restart the engine. He then capsized the boat while trying to get back onboard, according to the sheriff's office.
The pair drifted from the boat and toward the prison, Robinson said. Officials estimate they were in the water for up to 90 minutes, he said.
Deputies believe alcohol was a factor in the incident, and Laurel's death is being investigated by a coroner's office, the sheriff's office said.
The inmates in the prison's fire department are trained paramedics who were not convicted of violent or sexual offenses, Robinson said. He said they almost exclusively respond to emergencies inside the facility, and that this is the only water rescue involving the unit that he's aware of.
"Ninety-nine percent of what they do happens inside the facility," he said.
CNN's Amanda Watts contributed to this report.