I-EPA vial, eyaziwa nangokuthi i-Vial Ye-Environmental Protection Agency, iwuhlobo lwebhodlela eliyisampula elakhelwe ukuhlaziya indawo ezungezile, ikakhulukazi endabeni yokuhlolwa kwamanzi nomhlabathi. I-EPA isungule amazinga nemithethonqubo ethile yokuhlolwa kwemvelo, futhi izitsha ze-EPA zenzelwe ukuhlangabezana nalezi zidingo.
Izitsha ze-EPA ngokuvamile zenziwe ngezinto ezingasebenzi, njengengilazi ye-borosilicate, ukuze kuncishiswe ukusebenzisana phakathi kwesampula nebhodlela. Atholakala ngamasayizi ahlukene, ngokuvamile asukela ku-20 mL kuya ku-40 mL, ukuze athwale amavolumu amasampula ahlukahlukene.