A new study finds significant increases in the frequency and severity of emergency department visits due to marijuana exposures in children in Ontario, Canada, after the legalization of recreational marijuana.

The findings suggest that the introduction of edible marijuana products was a key factor associated with the increase in emergency department visits, the researchers said. The rise in emergency department visits occurred despite regulations aimed at minimizing unintentional use of marijuana by young people, UPI reports. The products are required to have plain packaging with warning symbols, and must be child-resistant.

Canada also placed limits on THC content, implemented marketing restrictions and began consumer education campaigns on marijuana safety. Many U.S. states that legalized recreational marijuana have not taken these steps, noted study author Daniel Myran at The Ottawa Hospital.

“Parents and caregivers can minimize the risk of cannabis exposures by keeping cannabis products in a locked container, away from other food and drinks and out of children’s reach,” Myran said.