Deuel County Sheriff Adam Hayward shows off a container of confiscated marijuana in Chappell, Neb., in July. Nikki Kahn/The Washington Post/Getty Images hide caption

itoggle caption Nikki Kahn/The Washington Post/Getty Images

Officials in Aspen have put out a brochure on how to use marijuana safely and legally. Marci Krivonen hide caption

itoggle caption Marci Krivonen

Trimmers prepare the marijuana flower, or bud, to make it more appealing to consumers. They use scissors to snip off the leaves and stems. Brett Myers/Youth Radio hide caption

itoggle caption Brett Myers/Youth Radio

Brooke Gehring, CEO of Patients Choice and Live Green Cannabis, stands in one of her company's grow houses in Denver. Kirk Siegler/NPR hide caption

itoggle caption Kirk Siegler/NPR

Edibles available at LoDo Wellness Center, a retail marijuana and medical marijuana dispensary and grow facility in downtown Denver. Matthew Staver/Landov hide caption

itoggle caption Matthew Staver/Landov

Amber McGowan, left, and Krystal Klacsan work Monday at Cannabis City in Seattle, a day before the store is to begin legal pot sales on Tuesday. The store will be for now the only one in Seattle to sell recreational marijuana. Ted S. Warren/AP hide caption

itoggle caption Ted S. Warren/AP