If you run an internet search on any dog treat, toy, food, medication ect you will find some report somewhere saying it's dangerous. My opinion is to just use some common sense. Watch your dog while they are using their toys or eating a treat. If they have a negative reaction, take it away and find a new kind to use for them.

My dogs get greenies occasionally. I give them when the dogs are in the truck or right after a vet app't. Never had a problem and the dogs love 'em.