  We present optical to radio spectral energy distribution fitting of the host
galaxies of four long gamma-ray bursts: 980703, 000210, 000418 and 010222,
which were detected at submillimetre and/or radio wavelengths. We find that
only very young starburst galaxy models are consistent with the data having
both blue optical colors and a pronounced submm emission. For each host we are
able to construct a model consistent with the short- and long-wavelength parts
of the spectra. We find galaxy ages ranging from 0.09 to 2.0 Gyrs and star
formation rates ranging from 138 to 380 MSun/yr.
