Among the various peculiar infinite-dilute near-critical phase behavior phenomena, one can mention "double retrograde vaporization" (DRV). This phenomenon is characterized by displaying two "domes" on the retrograde dew point curve, instead of the single-domed dew point curve in the familiar "single" retrograde condensation. This behavior had previously been observed in binary systems. This study shows that DRV also occurs in systems composed of a larger number of components. This is in line with a previous suggestion that the phenomenon of DRV is general. Experiments were carried out on the multi-component system ethane + orange peel oil, indicating quadruple-valued dew points at certain concentrations. Bubble point, dew point and critical point temperatures and pressures are presented for five different compositions ranging from 97.8 to 99.9 mass percent ethane. The data range within temperatures and pressures of 285-363 K and 3-7 MPa, respectively. The shapes and trends of DRV of the multi-component system ethane + orange peel oil are compared with those of the binary system ethane + limonene. (C) 2003 Elsevier B.V. All rights reserved.