(Adds background, research details, congressman, industrycomment)
By Doina Chiacu and Bill Berkrot
WASHINGTON/NEW YORK, Aug 11 (Reuters) - The U.S. DrugEnforcement Administration on Thursday denied requests to stopclassifying marijuana as a dangerous drug with no medical use,leaving users and businesses in limbo after many states havelegalized it for medical or recreational purposes.
The DEA did relax certain restrictions on growing marijuanafor research purposes.
For decades, marijuana has been listed as a "Schedule I"drug, placing it on par with heroin. The government hasrepeatedly rejected appeals for reclassification.
"Marijuana shouldn't be listed as Schedule I," U.S.Representative Earl Blumenauer, a Democrat from Oregon, said ina statement. He said the decision left "patients and marijuanabusinesses trapped between state and federal laws."
Twenty-five states have sanctioned some forms of marijuanause for medical purposes. Alaska, Washington, Oregon, Coloradoand the District of Columbia now allow recreational use foradults, while California and eight other states haverecreational or medical marijuana proposals headed for their2016 ballots.
The U.S. government has maintained that legalization of thedrug violates federal law, creating difficulties for marijuanabusinesses with issues such as banking.
Thursday's DEA decision was a response to a 2011 petition bytwo former state governors who had urged federal agencies tore-classify marijuana as a drug with accepted medical uses.
In a letter to the petitioners, the DEA said it had askedthe Department of Health and Human Services for a scientific andmedical evaluation.
"HHS concluded that marijuana has a high potential forabuse, has no accepted medical use in the United States, andlacks an acceptable level of safety for use even under medicalsupervision," the letter said.
That assessment comes amid statistics showing zero overdosedeaths due to marijuana each year at a time of an alarming riseof heroin-related deaths in the United States as politiciansdebate remedies for exploding opioid abuse.
Some experts have argued that medical marijuana could helpcut opioid use.
Taylor West, deputy director of the National CannabisIndustry Association, said the DEA's decision would curtailresearch since marijuana would remain a criminal product.
"Research institutions are going to be somewhat hesitant ifthey think they will potentially jeopardize other researchfunding," she said. "This decision by the DEA really flies inthe face of objective science."
Smart Approaches to Marijuana, an alliance of doctors,policy makers and treatment professionals who opposelegalization, took a different view.
"I think it was a balanced decision and isn't surprising tothe scientific community," said President Kevin Sabat.
The DEA will allow more growers to apply for certificationby the agency to help supply researchers "with a more varied androbust supply of marijuana." Now the University of Mississippiis the lone such supplier.
Britain's GW Pharmaceuticals, which is developing apromising cannabis-derived epilepsy treatment, has said it willtake longer to reach the U.S. market even with Food and DrugAdministration approval because it would then have to beseparately rescheduled by the DEA. (Additional reporting by Natalie Grover in Bangaluru and JilianMincer in New York; Editing by Alden Bentley and Lisa Von Ahn)
