Aplastic Anemia Associated With γ-Benzene Hexachloride

To the Editor.— It is frequently difficult, particularly in the case of widely used drugs and chemicals, to establish a causal relationship to an uncommon adverse effect like aplastic anemia. Until such a relationship is strongly suspected, however, physicians are not inspired to publish confirmatory evidence. This reluctance is unfortunate because it precludes early recognition of potential dangers. For this reason, one must take exception to Dr Zavon's contention (235:1841, 1976) that γ-benzene hexachloride is not suspect in the causation of aplastic anemia. There are at least 11 published cases of aplastic anemia¹⁻⁸and two of leukemia⁹with definite histories of exposure to γ-benzene hexachloride alone and with definite temporal relationships between exposure and clinical symptoms. There are at least ten others²,⁸,¹⁰⁻¹⁴in which γ-benzene hexachloride exposure was accompanied by exposure to additional materials also suspected of causing aplastic anemia. Five unpublished cases, apparently involving γ-benzene hexachloride