A 20-year-old Hilo man pleaded guilty in U.S. District Court Thursday morning to negligent homicide for causing a crash in the Hawaii Volcanoes National Park one year ago that killed his passenger.

Julien T. Quiocho pleaded guilty as part of a plea agreement with the prosecutor that calls for a 24-month prison term.

If U.S. District Judge David A Ezra imposes a higher sentence in September, Quiocho will be free to withdraw his guilty plea.

The maximum prison term for first-degree negligent homicide is 10 years.

The case is being handled in U.S. District Court because the federal government has jurisdiction in the park.

Federal prosecutor Michael Song said Quiocho was the driver of a pickup truck on Highway 11 on Jun. 12, 2011 when the truck left the roadway and crashed into a lava field. Quiocho and his passenger, 20-year-old Bryson Areola, also of Hilo, were thrown from the truck.

Areola was pronounced dead at Hilo Medical Center.

Song said blood taken from Quiocho at the hospital showed he had a blood alcohol content of 0.13.