Washington (CNN) -- Five midshipmen have been expelled from the U.S. Naval Academy as part of an ongoing investigation into the use of a synthetic drug called "spice," a spokeswoman for the school said Friday.
The expulsions are the latest disciplinary action at the academy since an investigation began last fall into spice use among midshipmen. In January, seven midshipmen were "separated from the Naval Academy" for violation of the Navy's policies on illicit substance abuse, officials said.
A spokeswoman for the academy said Friday that five more midshipmen were expelled, totaling 12 for the year.
"There have been four male 2nd class (juniors), six male 3rd class (sophomores), one male 4th class (freshman), and one female 3rd class midshipmen separated in conjunction with this investigation (totaling 11 males, 1 female)," according to Jennifer M. Erickson, a spokeswoman for the academy.
The Navy is working to combat the use of spice outside the academy as well.
In February, 16 sailors assigned to the Norfolk, Virginia-based USS Bataan were discharged for using or dealing the synthetic marijuana-mimicking drug.
"The number of incidents of spice usage is rising at an alarming rate in our Navy," Adm. John C. Harvey Jr., commander of U.S. Fleet Forces Command, said in a February statement.
"If you are considering using spice, I strongly urge you to reconsider," Harvey said. "If you are caught using it, even once, you will be processed for separation from the Navy. There is no second chance."
So far this year, eight Air Force Academy cadets have resigned because of spice use.
No West Point cadets have been expelled for using spice or similar substances during this academic year, a spokesman for the Army's U.S. Military Academy told CNN.
"Spice," also known as K2, is a mixture of herbs and spices that typically is sprayed with a synthetic compound chemically similar to THC, the psychoactive ingredient in marijuana, according to a Drug Enforcement Administration fact sheet.
"K2 is commonly purchased in head shops, tobacco shops, various retail outlets and over the Internet," the DEA said. "It is often marketed as incense or 'fake weed.'"
Its effects on the body are similar to that of marijuana.
While the synthetic drug is not yet considered illegal in the United States, the Defense Department and the Navy have banned its use.
The Drug Enforcement Administration, which must give the public 30 days' notice on substances it intends to ban, is currently in the process of placing an emergency ban on spice and other synthetic drugs.
The emergency ban will be in place for a year as federal officials study whether the products and chemicals should be permanently controlled, the agency said.