This paper examines the relationship between recruitment routes—internal transfers and external hires—and workplace accidents, comparing their relative impact. We propose that external hires are more likely to experience higher accident rates than internal transfers, as they must acquire both unit-specific and firm-specific knowledge. In addition, internal transfers, being more familiar with the organization, are less likely to suffer from this potential under the provision of integration resources. Using longitudinal data from French manufacturing establishments (2006-2015), our findings reveal that both internal transfers and external hires are positively associated with workplace accidents in the receiving unit. However, contrary to our expectations, we find no significant difference in accident rates between internal transfers and external hires. Additional analyses suggest that this lack of distinction may reflect the crucial role of unit-specific human capital in driving accidents, with internal transfers incurring substantial adjustment costs. Moreover, our results highlight the overestimation of transferability, with internal transfers benefiting less from integration resources. These findings contribute to the literature on human capital as a source of competitive advantage and the mobility literature, which contrasts the costs and benefits of internal versus external labor markets. They also offer practical insights for organizations regarding recruitment strategies and workplace safety management.