They are very inexpensive and worth your piece of mind. Always be sure to rinse the dog well. If you have a pet that likes to chew through electrical wires try covering them with a wide strip of electrical tape or spray exposed wires with pet repellant. Give your pet a weekly nose to tail exam. These bowls have been implicated as a health concern because the plastic may leach into the food.
All plastics release some undetectable fumes, especially when heated.
This out gassing means the fumes can pass into the foods that are served or stored in the bowl or container. Stainless steel or glass bowls are recommended.