The top federal prosecutor in Oregon on Friday pressed for data and details about the scope of the state's role as a source of black market marijuana.

U.S. Attorney Billy Williams told a large gathering that included Gov. Kate Brown, law enforcement officials and representatives of the cannabis industry that Oregon has an "identifiable and formidable overproduction and diversion problem."

"That is the fact," he told the crowd at the U.S. District courthouse. "And my responsibility is to work with our state partners to do something about it."

Added Williams: "Make no mistake. We are going to do something about it but that requires an effort to do this together. It requires transparency. The facts are what they are. The numbers are what they are."

Williams didn't detail how his office will carry out a new federal directive stripping legal protections for marijuana businesses. He said his office needs more information so it can accurately assess the scope of the problem and come up with a response.

Williams didn't say what data he's looking for, but he previously he has said he wants more information from the state about black market trafficking. In a recent opinion piece published in The Oregonian/OregonLive, Williams said he is awaiting a final version of a Oregon State Police report on the issue.

He convened a daylong "marijuana summit" where public health and law enforcement officials gave presentations, along with land owners and industry representatives.

He said Oregonians are worried about the implications of legal marijuana on their property rights, their water rights and the environment. Public health, particularly teen access and use, is a priority, he said.

"I am not an alarmist," he said. "Please don't have that perception of me. I just believe in looking at things head on. Take the blinders off, here are the realities."

The press was shut out of those presentations and was allowed only to report on statements offered by Williams and Brown.

U.S. Attorney General Jeff Sessions last month roiled Oregon's cannabis industry when he released a memo saying he would let federal prosecutors decide how aggressively to enforce federal marijuana law in states where the drug is legal.

Under President Obama, the federal government took a largely hands-off approach to recreational and medical marijuana, provided states developed robust regulations targeting illegal distribution.

In a document known as the Cole memo, federal authorities spelled out their marijuana enforcement priorities, which included cracking down on the black market, violent crime and keeping the drug from minors. Those guidelines served as a road map for states as they crafted rules.

Under federal law, marijuana remains a Schedule 1 drug, a category of drugs that includes heroin and is defined as substances that have a "high potential for abuse" and "no currently accepted medical use."

Brown also spoke briefly Friday, telling those gathered that Williams has assured her staff that "lawful Oregon businesses" are "not targets of law enforcement."

She didn't offer details on how the state will address Oregon's role as an illicit source of cannabis, saying only that she is committed to keeping cannabis in the state.

-- Noelle Crombie

ncrombie@oregonian.com

503-276-7184

@noellecrombie