  If gamma-ray bursts originate in dense stellar forming regions, the
interstellar material can imprint detectable absorption features on the
observed X-ray spectrum. Such features can be detected by existing and planned
X-ray satellites, as long as the X-ray afterglow is observed after a few
minutes from the burst. Detection of these X-ray features will make possible
the determination of the redshift of gamma-ray bursts even when their optical
afterglows are severely dimmed by extinction.
