Marijuana activists are criticizing -- and at least partly laughing off -- a counter-terrorism exercise carried out Wednesday in California that featured marijuana growers setting off bombs and seizing a dam.

Organized by the federal Bureau of Reclamation, the exercise involved 20 government agencies and some 250 personnel, according to a report from the Redding Record-Searchlight. In the scenario, marijuana growers blew up a bus and car and seized control of northern California's Shasta Dam in a bid to free an imprisoned colleague.

The Shasta Dam scenario began with the two mock bomb blasts followed by the “Red Cell” terrorist group taking over the dam in an effort to free one of their fellow marijuana growers from prison. Holding three people hostage, they threatened to flood the Sacramento River by rolling open the drum gates atop the dam. Those gates hold back the nearly full lake.

Jeff Stein at the Washington Post points out that "in a confidential catalog of terrorist threats, uncovered by Congressional Quarterly in 2005, the Department of Homeland Security did not include the region's marijuana growers." And marijuana advocates say there has never been a recorded case of marijuana-growing terrorists attacking public works.

"No, never," California NORML head Dale Gieringer told the Drug War Chronicle.

"That was so stupid," Geringer said of the exercise. "I don't know what inspired it. I can see the need to do better pat downs for air travelers to make sure they're not holding joints in their underpants, but this? It sounds like something some yahoo red county sheriff would dream up."

"This is a classic example of law enforcement's utterly inaccurate stereotype of who is involved with marijuana," a spokesman for the Marijuana Policy Project told the Chronicle. "For decades, they have [vilified] users and people involved in the industry to such an extent that they now equate them with terrorists."

The Record-Searchlight reports that the exercise was one of a series designed to improve security responses at major dams across the US.

Led by the Bureau of Reclamation — the federal agency that oversees the massive concrete dam that creates Lake Shasta — medical, fire and police agencies responded to the mock terrorist attack. During the drill the dam, the roads leading to it and a pair of popular fishing boat ramps were closed.

Part of the Bureau’s Critical Infrastructure Crisis Response Exercise Program, which started in 2003, the exercise was the first of its kind at the dam, Harral said. Similar drills took place at Utah’s Flaming Gorge Dam in 2003, Washington’s Grand Coulee Dam in 2005 and Hoover Dam on the Nevada-Arizona line in 2008. A similar drill is set for Folsom Dam next.