  Energies and lifetimes (widths) of vibrational states above the lowest
dissociation limit of $^{16}$O$_3$ were determined using a previously-developed
efficient approach, which combines hyperspherical coordinates and a complex
absorbing potential. The calculations are based on a recently-computed
potential energy surface of ozone determined with a spectroscopic accuracy [J.
Chem. Phys. {\bf 139}, 134307 (2013)]. The effect of permutational symmetry on
rovibrational dynamics and the density of resonance states in O$_3$ is
discussed in detail. Correspondence between quantum numbers appropriate for
short- and long-range parts of wave functions of the rovibrational continuum is
established. It is shown, by symmetry arguments, that the allowed purely
vibrational ($J=0$) levels of $^{16}$O$_3$ and $^{18}$O$_3$, both made of
bosons with zero nuclear spin, cannot dissociate on the ground state potential
energy surface. Energies and wave functions of bound states of the ozone
isotopologue $^{16}$O$_3$ with rotational angular momentum $J=0$ and 1 up to
the dissociation threshold were also computed. For bound levels, good agreement
with experimental energies is found: The RMS deviation between observed and
calculated vibrational energies is 1~\cm. Rotational constants were determined
and used for a simple identification of vibrational modes of calculated levels.
