Upper bounds on the EWs of lines with intrinsic width ﹩\sigma =0.1E﹩ (where E is the line energy). Magnetar atmosphere models predict that the EW of a proton cyclotron absorption line is of order 0.70–0.75E (Zane et al. 2001), although more recent work predicts EWs at least an order of magnitude lower (Ho & Lai 2002). For comparison, we have included lines that define ﹩\mathrm{EW}\,=0.5E﹩ and ﹩\mathrm{EW}\,=0.1E﹩. We conclude that the spectra show no strong absorption feature attributable to the proton cyclotron resonance in a magnetic field in the range of ﹩( 1.9{\mbox{--}} 9.8) \times 10^{14}﹩ G.