To evaluate the impact of back injuries on industry, the authors conducted a retrospective analysis of injuries occurring among a group of 31,200 employees of The Boeing Company, a large industrial manuacturer in Western Washington. They analyzed 4,645 injury claims (including 900 back injuries) made by 3,958 different employees. Two previous articles give an overview of the study, provide a detailed analysis of the costs associated with these back injuries, and analyze the characteristics of the injury. This article focuses on employee-related factors associated with back injuries. Claims were categorized according to severity, as indicated by total incurred cost (TIC), the sum of the medical costs, and indemnity costs. High-cost claims were defined as those with a TIC >$10,000 and low-cost claims as those with a TIC <$10,000. Employees younger than 25 years of age had a statistically significant increased risk of back injury, although their claims tended to be low-cost ones. This finding tends to discredit the premise that back problems are related to aging of the lumbar spine. While older employees had a lower injury rate, they did have a significantly increased risk of incurring high-cost back injury claims. The 31—40-year age group was the most susceptible to high-cost back injuries. Newer employees tended to have a significantly increased risk of back injury. The data show that women had fewer injuries than men but a statistically significant increased risk of becoming a high-cost injury claim. There was a correlation between incidence of back injuries and poor employee appraisal rating performed by the employee's supervisor within 6 months before the injury.