A lineup of medical-marijuana activists and business owners said today the state's proposed new rules for the cannabis industry threaten patient privacy.

Requirements that transactions at dispensaries be videotaped, purchases be documented and personal information be recorded could cause many of the state's more than 115,000 medical-marijuana patients to opt out of the system and return to buying pot on the street, advocates said. State officials say details of the purchases would be kept in a secure online database, but medical-marijuana advocates pointed to recent WikiLeaks disclosures as evidence that even guarded information can become public.

The advocates expressed their concerns this morning at the beginning of a two-day hearing on the rules, proposed by the state Revenue Department to regulate the thousands of medical-marijuana businesses that have sprung up in the last two years. About 30 advocates spoke during a public comment section of the hearing this morning.

"I am very concerned that many individuals ... will, due to the risk of having their information leaked, return to the black market," said Bruce Grainger, a dispensary owner who served on an advisory committee that helped craft some of the rules.

Read more: Denverpost.com