For years the Pennsylvania Department of Health allowed the state’s medical marijuana companies to sell hundreds of medicines that the agency now considers potentially unsafe.

Something changed in November when regulators started a process that led last month to a massive recall and ban of 670 types of cannabis concentrates for vaping — $12 million worth — they had previously approved for sale in Pennsylvania’s roughly 150 marijuana dispensaries.

The move blindsided patients and an industry dominated by companies hyper focused on broader legalization of marijuana. And regulators declined to explain the action beyond saying the medicines contained “added ingredients that have not been approved for inhalation” by the FDA.

The episode reveals the agency’s regulation of medical marijuana either to be weak – for allowing unsafe products to be sold, in some cases since the program began in 2018 — or capricious for mandating the recall of products it had previously approved without citing patient harm.

The program had more than 380,000 patients in November. Since early 2018, patients have spent $2.4 billion on medical marijuana.

The lack of information about adverse events concerns Deborah Miran, a former medical marijuana regulator in Maryland and an analytical chemist who spent decades filing drug applications to the FDA. [Read more at The Philadelphia Inquirer]