Before using a bottle to contain a chemical solution, chemical compatibility testing should be performed to ensure that the chemicals are compatible with the bottle material. As an example, we recently were asked to determine why a blow molded PVC bottle ruptured allowing gelled ethanol to spray onto a child. Ethanol is only marginally compatible with PVC. Residual stresses in te material from the blow molding process in combination with a large wall thickness variation in the bottle wall led to the bottle failure. Finited element analysis predicted the location of the failure.