Background Previous studies of workers' compensation claims for low back pain (LBP) have revealed that the preponderance of disability is borne by a fraction of cases. However, less is known regarding the in¯uence of occupational factors on these extreme conditions. Methods Workers' compensation claims (n 107,867) for LBP reported to a large, national insurer in 1992 were examined by antecedent event and industry class. In addition to summaries of the frequency and cost distribution, each factor was examined at two points on its cost distribution: one more representative of the typical case and one more representative of the case with long disability. These alternative disability indicators were introduced to explore a different perspective of LBP disability. Results The information provided by the alternative indicators was distinct from the information provided by the traditional aggregate indicators (claim frequency and claim cost frequency). In particular, this method identi®ed increased severity for claims in the construction and services sectors, as well as for claims arising from falls and motor vehicle crashes. Conclusions The results suggest that the construction and service sectors confront unique challenges to prevention and management of LBP disability. LBP related to discrete antecedents such as falls and motor vehicle crashes merits consideration on the basis of exceptionally severe disability.