Organigram, a federally licensed medical cannabis producer (LP) that voluntarily recalled contaminated products last year, said it conducted an “extensive investigation” but was unable to find the source for the tainted cannabis.

“We are determined to never have this happen again,” said Organigram CEO David Arsenault in a press release. “The inquiry was thorough and was undertaken with the full cooperation and assistance of Health Canada and outside experts.”

The LP also said it had reversed an earlier decision and now will refund money to patients who bought the contaminated products. The new decision comes as the company faces the prospect of class-action lawsuits due to some patients claims they’ve suffered serious health affects due to the contamination.

Halifax-based law firm Wagners says it is readying to proceed with a class-action lawsuit against Organigram and Canopy Growth. The firm said it could file suit as early as this week on behalf of patients, according to local radio station News 95.7.

Lawyer Ray Wagner says the number of complaints they received is quite high and has even resulted in some serious health concerns, including lung problems, rashes and ongoing nausea and vomiting.

“Well over 100 at this point in time,” said Wagners lawyer Ray Wagner. “It’s quite significant in terms of people’s concern. We’re hearing some stories from a number of individuals and in one particular case where she fell ill.”

The total cost of the refund is expected to be around $2.3 million ($1.7 million USD) and will more or less equal the company’s sales for its most recent quarter..

Organigram announced the voluntary recall last December after cannabis was found to have been contaminated with myclobutanil, a prohibited, mildew-fighting pesticide that produces hydrogen cyanide when burned.

Organigram maintains it didn’t knowingly use myclobutanil and that it may have ended up in its cannabis through contaminated peat moss – which it used only in 2016 – or fertilizer or soil.

In hopes of preventing a repeat of the incident, the company said it has:

  • Begun testing every product lot for pesticides before the cannabis can be sold.
  • Installed closed-circuit cameras in parts of the facility that previously didn’t have them.
  • Tightened the vetting of supplies – such as seeds, growing medium, fertilizers and water – from outside companies.

Canopy Growth also owns Mettrum, which recalled cannabis products in 2016 because they also were tainted with myclobutanil.