We all know that certain sulfur compounds are added to natural gas to make it detectable, and therefore safe to use as a commercial and domestic fuel. This is mature technology, however, some problems persist. One such problem is odorant masking. Cases have been reported in which utilities have purchased a large quantity of “odorized” natural gas from a reliable supplier. Upon taking delivery, a problem was immediately apparent: no odor. However, analysis using a sulfur chemiluminescence detector revealed a surprisingly high level of odorant. Although this observation is inconsistent, it is the potential key to the mystery. It is possible that the cause of odorant fading is the occurrence of odor masking among one or more gas components with the odorants. There are several manifestations of masking, including suppression, cross adaptation, and Zwaardermaker conjugation, the latter being the most striking. Zwaardemaker conjugates are pairs of compounds that individually have strong odors, but when combined in appropriate concentration ranges, produce mixtures with a very slight odor, or no detectable odor. We study several aspects of odor masking. First, we have begun working on small molecule–protein interactions with high field NMR. Second, we measure the vapor liquid equilibrium of odorants with liquids that may form odor agonists. Our research group has a central role because we have developed an international task force to study the problem. We recently held a workshop on the topic in Boulder, which included the entirety of the olfaction research community that is working on the masking problem. Therefore, this research opportunity affords the Associate with entre into nearly all aspects of research on the area.