Clear VOA Vials or borosilicate glass vials KaptClean for Volatiles are designed for EPA volatile organic analysis (VOA). This method is also known as Protocol B. Volatiles are chemicals that have high vapor pressures at room temperature (easily evaporate). They can include benzene, chloroform, toluene and carbon tetrachloride. Vials are pre-cleaned based on OSWER (Office of Solid Waste and Emergency Response) directives from the EPA (Environmental Protection Agency). All pre-cleaned containers are supplied pre-assembled with caps attached. Please note: Precleaned items are not returnable