Colorado governor signs recreational marijuana regulations into law DENVER (Reuters) - Governor John Hickenlooper on Tuesday signed into law measures to regulate the recreational use of marijuana in Colorado, including blood-level limits for motorists and setting up a voter referendum to impose a tax on the non-medical sale of cannabis. Colorado House of Representatives Assistant Majority Leader Dan Pabon said the legislation reflected the "will of the voters" who charged lawmakers with setting up the regulatory system after approving legalization in a vote last November. One of the bills signed by Hickenlooper calls for a referendum in November on setting a 15 percent excise tax and an additional 10 percent sales tax on marijuana sales. Other measures included in the legislative package are setting blood limits for driving while under the influence of marijuana at 5 nanograms per milliter, and limiting purchases of marijuana to non-Colorado residents at one-quarter of an ounce. "The laws ... signed today put the health and safety of our kids front and center," said Pabon, a Democrat. They drive a stake into the heart of a large black market while creating a regulated, legitimate industry. House Republican leader Mark Waller, who sponsored the driving-under-the-influence legislation, said Colorado is in "new and foreign territory" in implementing its marijuana laws and it was vital to add a public safety component. "Equipping law enforcement with the tools they need to ensure people make safe decisions behind the wheel is critical to maximizing public safety," he said. Voters in Washington state also approved legalizing recreational marijuana use last November. Mason Tvert, spokesman for the Marijuana Policy Project, which ran the campaign for the Colorado pot legalization ballot initiative, said it is "only a matter of time" before other states follow the lead of Colorado and Washington. He said Colorado's retail marijuana stores were expected to open in early 2014. Colorado and Washington are among nearly 20 states and the District of Columbia that allow the use of medical marijuana. The federal government still lists it as a dangerous narcotic and it remains illegal under federal law to take the drug for any purpose. After the Colorado legislature passed the bills, a spokesman for the U.S. Attorney's Office in Denver said the Justice Department was considering what its response will be to the marijuana legalization movement. In Washington state, the Liquor Control Board is required to establish regulations for the state's recreational marijuana industry. Earlier this month the agency released a set of draft rules that said marijuana must be grown indoors and tested for contaminants and potency. Licenses to grow, process and sell the drug would each cost $1,000 per year on top of a $250 application fee under the proposed guidelines.