U.S. troops are increasingly using an easy-to-get herbal mix called "Spice," which mimics a marijuana high, is hard to detect and can bring on hallucinations that last for days.

The abuse of the substance has so alarmed military officials that they've launched an aggressive testing program that this year has led to the investigation of more than 1,100 suspected users.

So-called "synthetic" pot is readily available on the Internet and has become popular nationwide in recent years, but its use among troops and sailors has raised concerns among the Pentagon brass.

"You can just imagine the work that we do in a military environment," said Mark Ridley, deputy director of the Naval Criminal Investigative Service, adding, "you need to be in your right mind when you do a job. That's why the Navy has always taken a zero tolerance policy toward drugs."

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