In the early days of NDACC (then NDSC), the Infrared Working Group (IRWG) targeted the retrieval of total columns of several gases considered of primary importance to the original goals of the Network. These goals focused on increasing our understanding of ozone chemistry and, in the post-Montreal Protocol period, observing the accumulation (and hopefully the eventual decline) of Cly and Fy in the stratosphere. Consequently, the initial gases targeted were ozone, nitric acid (HNO3), nitrous oxide (N2O ), chlorine nitrate (ClONO2), hydrogen chloride (HCl), and hydrogen fluoride (HF). As the Network matured and science questions evolved to encompass the broader issues of climate change, attributing causal relationships for observed changes in atmospheric composition, and air quality, the IRWG reevaluated the ability of high-resolution mid-IR Fourier Transform Spectrometers to contribute and address the new scientific issues. At the 2008 IRWG meeting, the group agreed to add methane (CH4), carbon monoxide (CO), hydrogen cyanide (HCN), and ethane (C2H6) to the existing suite of gases. All Principal Investigators in the IRWG maintain an archive of the recorded spectra since their observational program began, thereby allowing a re-analysis of these spectra. Consequently, the data record for the new gases will begin from the earliest observations for each site. Some of these data already are available to the public from the NDACC Data Host Facility. Many more will be archived during 2009.