A study is made of the 2D Ising model in the presence of quenched site disorder at low concentrations. The fermion representation of the Ising model is used and a parquet expansion approach is followed as in earlier work on the bond model by the present authors. A ln(ln(1/ mod T-Tc mod )) divergence in the specific heat is found, as in the bond case, demonstrating the expected universality. The authors also discuss the point group symmetry of the fermion representation. Finally the discussion is extended to general defects and it is shown that the specific heat divergence is universal for any type of low-concentration inhomogeneity.