Radiation hormesis: the demise of a legitimate hypothesis

This paper examines the underlying factors that contributed to the marginal ization of radiation hormesis in the early and middle decades of the 20th c entury. The most critical factor affecting the demise of radiation hormesis was a lack of agreement over how to define the concept of hormesis and qua ntitatively describe its dose-response features. If radiation hormesis had been defined as a modest overcompensation to a disruption in homeostasis as would have been consistent with the prevailing notion in the area of chemi cal hormesis, this would have provided the theoretical and practical means to blunt subsequent legitimate criticism of this hypothesis. A second criti cal factor undermining the radiation hormesis hypothesis was the generally total lack of recognition by radiation scientists of the concept of chemica l hormesis which was markedly more advanced, substantiated and generalized than in the radiation domain. The third factor was that major scientific cr iticism of low dose stimulatory responses was galvanized at the time that t he National Research Council (NRC) was organizing a national research agend a on radiation and the hermetic hypothesis was generally excluded from the future planned research opportunities. Furthermore, the criticisms of the l eading scientists of the 1930s which undermined the concept of radiation ho rmesis were limited in scope and highly flawed and then perpetuated over th e decades by other 'prestigious' experts who appeared to simply accept the earlier reports. This setting was then linked to a growing fear of radiatio n as a cause of birth defects, mutation and cancer, factors all reinforced by later concerns over the atomic bomb. Strongly supportive findings on her metic effects in the 1940s by Soviet scientists were either generally not a vailable to US scientists or disregarded as part of the Cold War mindset wi thout adequate analysis. Finally, a massive, but poorly designed, US Depart ment of Agriculture experiment in the late 1940s to assess the capacity for low dose plant stimulation by radionuclides failed to support the hermetic hypothesis thereby markedly lessening enthusiasm for research and funding in this area. Thus, the combination of a failed understanding of the hermet ic hypothesis and its linkage with a strong chemical hormesis database, fla wed analyses by prestigious scientists at the critical stage of scientific research development, reinforced by a Cold War mentality led to marginaliza tion of an hypothesis (i,e., radiation hormesis) that had substantial scien tific foundations and generalizability.