Two recent deaths and increased emergency room visits in Colorado have highlighted concerns about the safety of legal marijuana edibles.

Dr. George Sam Wang of Children’s Hospital Colorado says part of the problem is that the effects of edible marijuana begin more slowly than smokeable pot, though they tend to last longer.

“One of the dangers that we’ve been seeing with adult recreational retail use is they’ll take the recommended dose, wait, feel no effects and then continue to stack doses. Then before they know it they have a pretty large amount in their system and then they get potentially pretty severe effects,” he said.

Investigators say that appears to be what happened to Levy Thamba, a college student from the Republic of Congo who had never tried marijuana before. Friends say he ate the recommended dose of one-sixth of a marijuana-infused cookie on March 11. When he felt no effects he ate the entire cookie: six times the recommended dose. He later became irrational and jumped off a hotel balcony to his death. read the full story here and video here