  Gamma-ray bursts (GRBs) are the most violent explosions in the universe, seen
primarily as bright, short flashes of gamma-rays. Long GRBs are most likely
associated with the violent death of a very massive star. They are thus
believed to originate within regions of recent or ongoing star formation with
various bright, young stars, for instance, OB associations. GRBs have been
detected in gamma-rays by satellite-borne gamma-ray telescopes at MeV - GeV
energies, but could potentially also emit gamma-rays at even higher energies
(Very-High-Energy [VHE] gamma-rays: E > 100 GeV), as observed by ground-based
Cherenkov Telescope facilities, such as the High Energy Stereoscopic System
(H.E.S.S) in Namibia. VHE gamma-rays can be absorbed by low energy photons by
pair production, and the stars in the vicinity of a GRB provide a dense
radiation environment, which could lead to such absorption. We have
investigated representative GRB environments and provide an estimate of the
opacity to gamma-gamma absorption for VHE gamma-rays from GRBs. We find that
for the likely properties of OB associations around GRB progenitors,
gamma-gamma absorption is expected to be negligible.
