The production of hadrons in Ni-Ni at the GSI laboratory is considered in a hadronic gas model with chemical equilibrium. Special attention is given to the abundance of strange particles which are treated using the exact conservation of strangeness. It is found that all the data can be described using a temperature T ϭ70Ϯ10 MeV and a baryon chemical potential B ϭ720Ϯ30 MeV. ͓S0556-2813͑98͒01706-3͔