This two-study paper presents why and how work overload and insomnia can relate to workplace injuries in service companies serving the offshore and onshore oil and gas industry. Utilizing the self-regulatory resource theory, we argue that both overload and insomnia decrease workers' safety behaviors, resulting in increased workplace injuries. Moreover, in order to ultimately derive organizational interventions to alleviate the detrimental impact of insomnia on workplace injuries, we propose that supervisor safety priority can create situation strength that can prevent workers from behaving unsafely despite experiencing high workload and insomnia. We present two studies testing the insomnia-safety outcome and overload-safety outcome relationships respectively. Results were consistent with the proposed conceptual framework, the relationship between insomnia and injuries is explained by the influence of insomnia on safety behaviors, and the relationship between overload and outcomes was also alleviated through situation strength. For employees supervised by supervisors with high safety priority, both the relationship between insomnia and safety behaviors and the indirect relationship between insomnia and workplace injuries were weaker. We propose theoretical implications for future safety research and suggest tentative directions for practitioners working to reduce workplace injuries through work overload and sleep-oriented interventions.