EPA / VOA Vials. These VOA Vials are made of laboratory quality borosilicate glass as recommended by the EPA. The open top caps are made from a glass reinforced polypropylene resin, and the septa is made from Virgin Teflon® and FDA grade silicone. The Precleaned (2000 class) and QA Analyzed (3000 class) vials are washed to EPA Protocol "B".