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The red damping wing from neutral hydrogen in the intergalactic medium is asmoking-gun signal of ongoing reionization. One potential contaminant of theintergalactic damping wing signal is dense gas associated with foregroundgalaxies, which can give rise to proximate damped Ly$\alpha$ absorbers. TheLy$\alpha$ imprint of such absorbers on background quasars is indistinguishablefrom the intergalactic medium within the uncertainty of the intrinsic quasarcontinuum, and their abundance at $z\gtrsim7$ is unknown. Here we show that thecomplex of low-ionization metal absorption systems recently discovered by deepJWST/NIRSpec observations in the foreground of the $z=7.54$ quasarULAS~J1342$+$0928 can potentially reproduce the quasar's spectral profile closeto rest-frame Ly$\alpha$ without invoking a substantial contribution from theintergalactic medium, but only if the absorbing gas is extremely metal-poor($[{\rm O}/{\rm H}]\sim-3.5$). Such a low oxygen abundance has never beenobserved in a damped Ly$\alpha$ absorber at any redshift, but this possibilitystill complicates the interpretation of the spectrum. Our analysis highlightsthe need for deep spectroscopy of high-redshift quasars with JWST or ELT to"purify" damping wing quasar samples, an exercise which is impossible for muchfainter objects like galaxies.

Possible Contamination of the Intergalactic Medium Damping Wing in ULAS J1342+0928 by Proximate Damped Ly$\alpha$ Absorption