  In the paper "Big Bang Nucleosynthesis and Active-Sterile Neutrino Mixing:
Evidence for Maximal Muon-Neutrino/Sterile-Neutrino Mixing in Super Kamiokande"
(astro-ph/9810075), we suggested that to evade the Big Bang Nucleosynthesis
exclusion of the muon neutrino to sterile neutrino oscillation explanation of
the Super Kamiokande data, the tau neutrino must have a mass over about 15 eV
and it must mix with a lighter sterile neutrino. A stable tau neutrino with
this mass is inconsistent with cosmological structure formation. In a comment
on our paper (astro-ph/9811067), Foot and Volkas argued that our result is
incorrect and that the required tau neutrino mass should be much lower. Here we
back up our original result with a more detailed calculation. We show that the
argument of Foot and Volkas is invalid, most likely due to an insufficient
energy resolution in the low energy part of the neutrino spectrum.
