  We show how the measured particle ratios can be used to provide non-trivial
information about the critical temperature of the QCD phase transition. This is
obtained by including the effects of highly massive Hagedorn resonances on
statistical models, which are used to describe hadronic yields. The inclusion
of Hagedorn states creates a dependence of the thermal fits on the Hagedorn
temperature, $T_H$, which is assumed to be equal to $T_c$, and leads to an
overall improvement of thermal fits. We find that for Au+Au collisions at RHIC
at $\sqrt{s_{NN}}=200$ GeV the best square fit measure, $\chi^2$, occurs at
$T_c \sim 176$ MeV and produces a chemical freeze-out temperature of 172.6 MeV
and a baryon chemical potential of 39.7 MeV.
