Published: Jul 24, 2014 11:16 AM EDT

KEY LARGO, Fla. (AP) - A New Jersey man is dead following a diving trip in the Florida Keys with his teenage children.
    
Monroe County Sheriff's officials say 45-year-old Gary Lanier of Kenvil, New Jersey, died Wednesday off of Key Largo.
    
Witnesses and his children, ages 15 and 18, told deputies Lanier began having trouble as he surfaced from his dive. One of the dive mates began assisting him and helped get him onto the vessel.
    
According to an incident report, he became unresponsive on the boat and CPR was started.
    
The U.S. Coast Guard responded and brought Lanier to the marina, where paramedics met them. Lanier was taken to Mariner's Hospital, where he was pronounced dead.
    
An autopsy is being done to determine the cause of death.

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