  We study spectral properties of the phi meson at finite temperature using an
effective Lagrangian together with finite-temperature field theory as a basis
for modeling. General field-theoretic arguments are then used to establish the
lifetime of the phi in hot hadronic matter. We find from the model, and we
therefore propose a scenario in which, the phi decays inside the fireball.
Early decays into $\mu^{+}\mu^{-}$ occur at high temperature while measurable
hadronic decays into $K^{+}K^{-}$ (not suffering rescattering) occur at
freezeout, where flow could be substantial. These results provide a consistent
picture, if not possible interpretation of the NA49 and NA50 data from CERN.
