In August, a state analyst spotted dozens of suspicious transactions when he crunched cannabis sales data: a small number of medical marijuana cardholders bought unusually large quantities of marijuana flowers on consecutive days.

Oregon regulators suspected medical marijuana patients and caregivers were exploiting the system by buying cannabis to sell on the illicit market.

The response was swift. The Oregon Liquor Control Commission, under pressure from federal officials to tackle the robust black market for marijuana, quickly issued a temporary rule that dramatically reduced the amount that medical marijuana cardholders could buy in a day.

The limit dropped from a pound and a half of marijuana to 1 ounce -- the same quantity recreational cannabis consumers are allowed to buy.

"What we saw was abuse, clear abuse of the standards," Steve Marks, executive director of the Liquor Control Commission, said Wednesday.

Over 19 days in August, for instance, one medical marijuana cardholder bought nearly 13 pounds of cannabis. Another bought 7 pounds over 10 days that month. Officials said the questionable transactions came from a small percentage of cardholders and that the typical purchase for most cardholders was 4 grams or less.

Marks said marijuana program overseers worried that the state's low marijuana prices enticed some cardholders to stock up and "take it to Iowa or wherever and sell for a profit."

"We saw that happening," he said, adding it was "a little bit of a Ponzi scheme."

Oregon has been in the crosshairs of U.S. Justice Department leaders for not doing enough to crack down on the black market. U.S. Attorney Billy Williams has repeatedly expressed frustration with the state's failure to contain production and he's chided top officials for not devoting enough resources to oversight and enforcement.

On Wednesday, patients and advocates for the medical marijuana program blasted the new limits at a contentious meeting of the state's rules advisory committee.

Advocates said medical marijuana patients sometimes need large quantities of the drug to make products they rely on to treat their conditions and they accused the state of meddling with medicine.

The rules committee, made up of marijuana industry participants and advocates, called on the Liquor Control Commission to restore daily purchase limits to 24 ounces.

The at-times boisterous crowd included some of the same activists who have long championed Oregon's 20-year-old medical marijuana program since its early days. For many, the rule reflects the latest change to a program that has experienced a steep drop-off in participation since voters approved recreational marijuana in 2014.

State statistics show Oregon has about 39,000 medical marijuana patients, down from 78,000 in 2015. The number of grow sites serving three or more patients has also plummeted from about 4,000 in 2015 to about 800 today, according to Anthony Taylor, a longtime advocate.

Cannabis is tax-free for medical marijuana patients. They also are allowed to buy more potent edibles and oils than recreational users, and until the latest rule change, they could buy more cannabis flower.

It remains a vital program for those who remain, supporters said.

Brent Kenyon, a licensed producer, processor and retailer based in Medford, accused regulators of scapegoating medical marijuana cardholders for black market diversion when recreational producers do the same.

"You cannot punish everybody for the few bad actors," he said. "You can't do it. It's not good policy."

During a particularly tense exchange, Jesse Sweet, the lawyer who has helped draft the state's rules for Oregon's legal marijuana market, asked Dr. Rachel Knox, a member of the advisory committee, to explain why one person would need so much cannabis.

"I need you to explain to me why a patient needs 6 pounds of flower," he said. Knox countered by saying the state had no proof that the transactions were linked to illegal activity and she wouldn't rule out that one person could have a legitimate medical need for a large quantity.

It was a claim that Sweet found incredulous, using an expletive to express his disbelief.

Sweet, the administrative policy and process director for the Liquor Control Commission, then got up and walked out of the crowded meeting. He eventually returned and apologized for losing his temper.

Marks, after the meeting, struck a diplomatic note, saying he was encouraged by the lively discussion and some of the advocates' proposals, including allowing patients to buy more marijuana based on a doctor's recommendation.

"We are going to look at it," he said. "We are listening."

-- Noelle Crombie

503-276-7184

@noellecrombie