  We report the discovery of a high-ionization broad absorption line system at
a redshift of z_abs=0.695 in the spectrum of the z_em=1.052 radio-quiet quasar
PG 2302+039. Broad absorption with FWHM from 3,000 to 5,000 km/s is detected
from C IV, N V, and O VI in HST Faint Object Spectrograph spectra of the
quasar. A narrow line system (FWHM approximately 250 km/s) at z_abs=0.7016 is
resolved from the broad blend and includes absorption by Ly-alpha and the C IV,
N V, and O VI doublets. No absorption by low-ionization metal species (e.g. Si
II and Mg II) is detected in the HST or ground-based spectra for either the
broad or the narrow system. The centroids of the broad system lines are
displaced by approximately 56,000 km/s to the blue of the quasar's broad
emission lines. The reddest extent of the broad line absorption is more than
50,000 km/s from the quasar. The properties of this system are unprecedented
whether it is an intervening or an ejected system.
