I probably was a little hasty in calling them dangerous, but they do have harmful affects. The Government of Canada's Cancer Research center has classified that all soft plastics are harmful to human heath, and thus even more so to fish health. It's more of a precusion, than a warning. Sorry to make it sound so bad, that wasn't my intention! And I don't mean to offend anyone!
PS-and we may be talking about different products as well. there are blue stock barrels that are completely safe becasue they are made out of hard plastic rather than soft.