Using marijuana for recreational use is now effectively legal in Colorado.
    
Gov. John Hickenlooper declared a voter-approved marijuana legalization amendment as part of the state constitution on Monday. It was the last procedural step needed for the amendment to take effect.
    
The drug became legal in Washington state last week.
    
Hickenlooper tweeted his declaration and announced it to reporters by email. The Democratic governor said voters were "loud and clear" when they voted last month to make pot legal without a doctor's recommendation. Adults over 21 may now possess up to an ounce of marijuana, or six plants.
    
Colorado and Washington officials both have asked the U.S. Department of Justice for guidance on the laws that conflict with federal drug law. Neither state will allow commercial sales for a year or more.