Controlled Substances Act
During these investigations, the DEA gathers a lot of information, talks to different government agencies, gets the FDA's opinion, and does research.  Because all of this takes time, a federal law allows the Attorney General of the United States to put a drug on Schedule I for a year.  The law only allows this when there is "an imminent hazard" (an immediate threat) "to the public safety."  For example, in 2011, the Attorney General used this law to put synthetic cannabinoids on Schedule I.