Washington (CNN) -- Effective Tuesday, "Spice" will not be a legal alternative to pot. The Drug Enforcement Administration is making the sale and possession of synthetic marijuana illegal for at least one year.
The agency says the action is necessary "to avoid an imminent hazard to the public safety."
The ban that takes effect Tuesday was announced by the DEA in November, with the agency saying then it would make possessing and selling the chemicals used to produce synthetic marijuana illegal in the United States for at least one year while the DEA and the Department of Health and Human Services study whether the chemicals should be permanently controlled.
Five chemicals most commonly found in products like "Spice" and "K2" are being classified as Schedule I controlled substances, a category reserved for unsafe, highly abused substances with no medical usage. The DEA said in November it was using its "emergency scheduling authority" to temporarily control the chemicals.
The drugs are manufactured overseas and are typically laced on plant material and sold as herbal incense or plant food. They create a marijuana-like high when smoked.
According to the DEA, increased use of synthetic marijuana has lead to a surge in emergency-room visits and calls to poison-control centers. Adverse health effects associated with its use include seizures, hallucinations, paranoid behavior, agitation, anxiety, nausea, vomiting, racing heartbeat and elevated blood pressure.
"Fake pot" has already been banned in 18 states and several countries. All five branches of the U.S. military prohibit military personnel from possessing or using them.