The iron emission line in the X-ray afterglow spectra of a Gamma-Ray Burst is thought to be a key to understanding the environment of progenitors. Although two independent observations with BeppoSAX and ASCA reported strong red-shifted iron emission line, the statistical significance of these detections was not very high. Further observations were expected and two more GRBs, GRB 990123 and GRB 990704, were observed with the X-ray satellite ASCA in 1999. The spectra of these two afterglows can be explained by a simple power-law model with excess absorption, but without any iron emission-line feature. The 90% upper limit for the iron line flux is as low as FFe = 3.3 x 10-6 {photons cm-2 s-1}, or less than ~ 100 {eV} in equivalent width (EW). This upper limit is an order-of-magnitude smaller than the previous two detections of 1-3 keV in EW.
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