The risk is very small. PVC pipes and plastics in general have been around for a few generations now.
Life without risk would be paradise, reality is unless you live in a bubble there is risk everywhere.
Take a breath, there are dust mites and chemicals in the air you breathe.
Everytime you leave your house to interact with the world if you take a walk around the block (you could get hit by a car), if you bike ( same thing), get in your car ( the chances are good that you will get into at least one accident in your lifetime). Even staying in the house, you could fall in the house, slip in the bathtub, fall down the stairs, someone could break in to the house or someone in the house or a neighbor may have a psychotic episode and go berserk.
You can get food poisoning from your organic lettuce if the farmer does not know that a cow pasture upsteam is contaminating his field or if the workers handling the produce on the farm or in the store or anywhere along the line passes on some germs.
Baby cribs, cars, seat belts, air bags, car seats, toys are recalled all of the time. There is just no such thing as zero risk. All you can do is make reasonable choices and assume reasonable risk.
You want to keep your family safe and you can control some things but there are no guarantees in life except that at some point, each individual will have to learn to make their own choices, you cannot foresee the future, death is inevitable, and life is for the living not the worrying.
Happy gardening in Hawaii. Gardens are where people grow.