This study examined the sensitivity and false-positive error rate of reliable digit span (RDS) and the WAIS-III Digit Span (DS) scaled score in persons alleging toxic exposure and determined whether error rates differed from published rates in traumatic brain injury (TBI) and chronic pain (CP). Data were obtained from the files of 123 persons referred for neuropsychological evaluation related to alleged exposure to environmental and industrial substances. Malingering status was determined using the criteria of Slick, Sherman, and Iverson (1999). The sensitivity and specificity of RDS and DS in toxic exposure are consistent with those observed in TBI and CP. These findings support the use of these malingering indicators in cases of alleged toxic exposure and suggest that the classification accuracy data of indicators derived from studies of TBI patients may also be validly applied to cases of alleged toxic exposure. (Contains 4 tables.)