  The most abundantly produced hadron species in $Si\!-\!Au$ collisions at the
BNL-AGS (nucleons, pions, kaons, antikaons and hyperons) are shown to be in
accord with emission from a thermal resonance gas source of temperature
$T\simeq 110$ MeV and baryochemical potential $\mu_B \simeq 540$ MeV,
corresponding to about 1/3 standard nuclear density. Our analysis takes the
isopin asymmetry of the initial state fully into account.
