Hi,
My husband used to be a chemist and he says that there really isn't anything wrong (environmentally) with using Draino because it breaks down into its components *really* quickly in the water system. And we use nothing but natural cleansers, etc. in our home, so he really means it. Our tubs clogs up all the time and we use it. Just make sure not to use anything like vinegar or baking soda at the same time as Draino because it reacts very easily with any other chemicals.