Abstract: The greatly expanded atmosphere of Eta Carinae and the surrounded nebulosities enshrouds the stellar system lying deep within. We focus on two Hubble Space Telescope/Space Telescope Imaging Spectrograph (HST/STIS) spectra of the Weigelt Blobs B&D, March 1998 and February 1999. The long-aperture spectra suggest two distinct ionization regions. One region is represented by the permanent emission from H I, [N II], Fe II, [Fe II], Ni II, [Ni II], Cr II and Ti II. The second region is characterized by highly ionized emission from [Fe III], [Fe IV], N III], [Ne III], [Ar III], [Si III], [S III] and He I. Based on our photoionization modeling, we derived physical conditions and elemental abundances of the nebulosities. We also obtained properties of the radiation field of the primary massive star and its companion. In addition, we show that while C and O appear highly depleted, the molecule formation including these elements is possible in the vicinity of Eta Carinae.