  The hadronic particle production data from relativistic nuclear Pb--Pb 158 A
GeV collisions are successfully described within the chemical non-equilibrium
model, provided that the analysis treats Omega and anti-Omega abundances with
care. We further show that there is a subtle influence of the Coulomb potential
on strange quarks in quark matter which is also seen in our data analysis, and
this Coulomb effect confirms the finding made by chemical analysis in the
S--Au/W/Pb 200 A GeV collisions that the hadron particle source is deconfined
with respect to strange quark propagation. Physical freeze-out conditions
(pressure, specific energy, entropy, and strangeness) are evaluated and
considerable universality of hadron freeze-out between the two different
collision systems is established.
