<P> Hemp was made illegal to grow without a permit in the U.S. under the Controlled Substances Act passed in 1970 because of its relation to marijuana , and any imported hemp products must meet a zero tolerance level . Some states have made the cultivation of industrial hemp legal , but farmers in many states have not yet begun to grow it because of resistance from the federal Drug Enforcement Administration , making `` large - scale hemp growing '' in the United States `` not viable '' as late as 2013 . In 2013 , after the legalization of cannabis in the state , several farmers in Colorado planted and harvested several acres of hemp , bringing in the first hemp crop in the United States in over half a century . Colorado , Vermont , California , and North Dakota have passed laws enabling hemp licensure . All four states are waiting for permission to grow hemp from the DEA . Currently , Oregon has licensed industrial hemp as of August 2009 . Congress included a provision in the Agricultural Act of 2014 that allowed colleges and state agencies to grow and conduct research on hemp in states where it is legal . Hemp production in Kentucky , formerly the United States ' leading producer , resumed in 2014 . </P>
<P> Hemp was made illegal to grow without a permit in the U.S. under the Controlled Substances Act passed in 1970 because of its relation to marijuana , and any imported hemp products must meet a zero tolerance level . Some states have made the cultivation of industrial hemp legal , but farmers in many states have not yet begun to grow it because of resistance from the federal Drug Enforcement Administration , making `` large - scale hemp growing '' in the United States `` not viable '' as late as 2013 . In 2013 , after the legalization of cannabis in the state , several farmers in Colorado planted and harvested several acres of hemp , bringing in the first hemp crop in the United States in over half a century . Colorado , Vermont , California , and North Dakota have passed laws enabling hemp licensure . All four states are waiting for permission to grow hemp from the DEA . Currently , Oregon has licensed industrial hemp as of August 2009 . Congress included a provision in the Agricultural Act of 2014 that allowed colleges and state agencies to grow and conduct research on hemp in states where it is legal . Hemp production in Kentucky , formerly the United States ' leading producer , resumed in 2014 . </P>
when did hemp become illegal in the us
when did hemp become illegal in the us
1970
1970