Most are made from flexible PVC. there should be mo reason they could not be used safely and quite a few people have used them w no ill effects. this is from another thread on a different site and the same discussion...
I bought one of Fernco's PlumbQwik 4"x4" couplers to use on my skimmer instead of paying though the nose for a 4" PVC Union. I wasn't sure if it was safe so I decided to find out.
I called Fernco the company that makes them, and talked to one of their engineers about it's properties & safety. He said that it is not "officially" not made of food-grade materials so they can't recommend it for drinking water situations; however, they don't have any reason to beleive that it is in anyway toxic. It is made from plasticized PVC so based on that it should be safe.
Aquatice Ecosystems I guess has been buying & using these fittings from them for years with no reported problems, and a while ago, they came to Fernco about making food-grade versions. Supposedly AE got some flack from someone that they were concerned that the plasticizer could mimic estrogen, except they didn't have any trials or studies backing up this theory. Fernco did make them some parts out of food grade materials that were actually the translucent light blue color of "clear" PVC, but disagrees with their plasticizer estrogen theory.
He also explained breifly how the FDA tests for food-safe, and said it a function of the material properties along with the amount of material that is in contact with the water at any given time.
The guy at Fernco checked if they had any extras lying around that he might be able to sell me, but they didn't. He suggested I go to AE
That said, I decided to go to the AE website to see if they sold the food-grade and lone behold I found that they sell the regular ones which they simply tag as "Not FDA-approved for potable water". They definitely aren't made from the bluish/translucent food-grade materials and look to me to be exactly the same as the ones sold in Menards/HD.
http://www.aquaticeco.com/index.cfm/.../6958/cid/1878
So, all that said, I certainly feel fine using these things as a union in my skimmer, especially since there's very little surface area contacting the water since it's on the outside of both sections.
That's all I know so you can make your own semi-informed decision for using it in your durso.
