Eric McDavid, 29, who was found guilty in March on conspiracy to damage or destroy property by fire and an explosive, was sentenced to roughly 19 and a half years prison at a hearing in Sacramento, northern California.

Two other co-conspirators, Zachary Jenson and Lauren Weiner, have already pleaded guilty in the case and are awaiting sentencing later this year.

Prosecutors said the three environmental militants had planned attacks on the US Forest Service's Institute of Forest Genetics, a dam and fish hatchery, cellular telephone towers and electric power stations.

Bomb-making expertise was acquired from a book -- "Poor Man's James Bond" -- which contains details of how to create home-made explosive devices, justice officials said. The three extremists were arrested in January 2006 after buying materials for the explosives and finalizing their targets, prosecutors said.

"Today's severe punishment of nearly 20 years in federal prison should serve as a cautionary tale to those who would conspire to commit life-threatening acts in the name of their extremist views," US Attorney McGregor Scott said.

Weiner will be sentenced on May 15, followed by Jenson on August 7.

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