The scientific community engaged in research practices of high-energy physics in megascience laboratories is constituted by various subcommunities. These subcommittees are involved in engineering activities and preoccupied by phenomenal analyses. In recent decades, interdisciplinary accelerator and detector researchers, whose work is rooted in engineering, have replaced the experimentalists and instrumentalists of the 1970s; however, the role of pure theorists has remained essentially unchanged. In this article, the author clarifies the roles and specializations of these groups and explicate community members' blurred professional identities; the emphasis lies on engineering specialists and experimentalists. This research also attempts to clarify the reasons for the substantial imbalance of prestige among groups and how it is associated with access to highly valued epistemic practices such as articulating statements regarding natural phenomena. This paper applies an ethical theory framework to reveal how the lack of access to phenomenal knowledge expression—despite mediated contribution to knowledge production—creates participatory epistemic injustice. Finally, the author suggests ways to address this problem.