  Sulfur abundances are derived for a sample of ten B main-sequence star
members of the Orion association. The analysis is based on LTE plane-parallel
model atmospheres and non-LTE line formation theory by means of a
self-consistent spectrum synthesis analysis of lines from two ionization states
of sulfur, SII and SIII. The observations are high-resolution spectra obtained
with the ARCES spectrograph at the Apache Point Observatory. The abundance
distribution obtained for the Orion targets is homogeneous within the expected
errors in the analysis: A(S)=7.15+/-0.05. This average abundance result is in
agreement with the recommended solar value (both from modelling of the
photospheres in 1-D and 3-D, and meteorites) and indicates that little, if any,
chemical evolution of sulfur has taken place in the last ~4.5 billion years.
The sulfur abundances of the young stars in Orion are found to agree well with
results for the Orion nebulae, and place strong constraints on the amount of
sulfur depletion onto grains as being very modest or nonexistent. The sulfur
abundances for Orion are consistent with other measurements at a similar
galactocentric radius: combined with previous results for other OB-type stars
produce a relatively shallow sulfur abundance gradient with a slope of
-0.037+/-0.012 dex/kpc.
