  We have carried out an extensive search for gamma-ray lines in the first year
of public data from the Spectrometer (SPI) on the INTEGRAL mission. INTEGRAL
has spent a large fraction of its observing time in the Galactic Plane with
particular concentration in the Galactic Center (GC) region (~ 3 Msec in the
first year). Hence the most sensitive search regions are in the Galactic Plane
and Center. The phase space of the search spans the energy range 20-8000 keV
and line widths from 0-1000 keV (FWHM). It includes both diffuse and point-like
emission. We have searched for variable emission on time scales down to ~ 1000
sec. Diffuse emission has been searched for on a range of different spatial
scales from ~ 20 deg (the approximate field-of-view of the spectrometer) up to
the entire Galactic Plane. Our search procedures were verified by the recovery
of the known gamma-ray lines at 511 keV and 1809 keV at the appropriate
intensities and significances. We find no evidence for any previously unknown
gamma-ray lines. The upper limits range from a few x 10^-5 cm^-2 s^-1 to a few
x 10^-2 cm^-2 s^-1 depending on line width, energy and exposure; regions of
strong instrumental background lines were excluded from the search. Comparison
is made between our results and various prior predictions of astrophysical
lines.
