| Summary: | A critical survey of the abundant literature on environmental remediation and water treatment using metallic iron (Fe<sup>0</sup>) as reactive agent raises two major concerns: (i) the peculiar properties of the used materials are not properly considered and characterized, and, (ii) the literature review in individual publications is very selective, thereby excluding some fundamental principles. Fe<sup>0</sup> specimens for water treatment are typically small in size. Before the advent of this technology and its application for environmental remediation, such small Fe<sup>0</sup> particles have never been allowed to freely corrode for the long-term spanning several years. As concerning the selective literature review, the root cause is that Fe<sup>0</sup> was considered as a (strong) reducing agent under environmental conditions. Subsequent interpretation of research results was mainly directed at supporting this mistaken view. The net result is that, within three decades, the Fe<sup>0</sup> research community has developed itself to a sort of modern knowledge system. This communication is a further attempt to bring Fe<sup>0</sup> research back to the highway of mainstream corrosion science, where the fundamentals of Fe<sup>0</sup> technology are rooted. The inherent errors of selected approaches, currently considered as countermeasures to address the inherent limitations of the Fe<sup>0</sup> technology are demonstrated. The misuse of the terms “reactivity”, and “efficiency”, and adsorption kinetics and isotherm models for Fe<sup>0</sup> systems is also elucidated. The immense importance of Fe<sup>0</sup>/H<sub>2</sub>O systems in solving the long-lasting issue of universal safe drinking water provision and wastewater treatment calls for a science-based system design.
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