The United States Drug Enforcement Administration on Tuesday banned products labeled as incense and marketed as Spice, K2, Blaze or Red X Dawn.
It is also illegal to sell the five chemicals used to make the products, the DEA said. The chemicals are used to coat plant material and claim to mimic THC, the active ingredient in marijuana.
The temporary measure will remain in effect for at least one year while the DEA and the U.S. Department of Health and Human Services further study whether these chemicals should be permanently controlled.
They have been designated as Schedule I substances, the most restrictive category under the Controlled Substances Act. To be classified as Schedule I, a substance has a high potential for abuse, no accepted medical use for treatment in the United States and a lack of accepted safety for use of the drug under medical supervision.
"Young people are being harmed when they smoke these dangerous ‘fake pot' products and wrongly equate the products' legal retail availability with being safe, " said DEA Administrator Michele M. Leonhart.
In Cowlitz County, fake pot caught the attention of doctors and anti-drug groups last summer after young people claiming to have smoked the drug came into the emergency department at St. John Medical Center with high anxiety and sometimes dangerously fast heartbeats.
Synthetic marijuana is "definitely causing a different set of symptoms" than conventional pot, Dr. Brian Hoyt said in December when the DEA announced a temporary ban.