Certain ternary mixtures of near-critical carbon dioxide + n-alkanols + tetradecane have been found to display unexpected fluid multiphase equilibria. For instance, it was found that in the systems with decanol, octanol, or heptanol the three-phase liquid-liquid-vapor surface contains a two-phase liquid-vapor region which is completely bounded by a closed loop critical endpoint locus of the type liquid = liquid + vapor (l(1) = l(2) + g). The occurrence of such ＇＇holes＇＇ indicate that at conditions encountered in supercritical fluid operations, the phase behavior might be more complex than expected, and may have consequences in process design.