Human safety and health, environmental and property protection and security concerning hazardous materials supply chain are important issues for many countries, industries and organisations around the world. This paper presents some key results of a comprehensive risk study on hazardous materials supply chain incidents. Based on a risk analysis framework adapted for maritime transport of packaged dangerous goods, this study combines qualitative and quantitative analysis of large and diverse datasets collected from some of the U.S.'s best and largest data sources. The study may be one of the largest of its kind, and some of the results might not be found elsewhere. Incidents have occurred in every system of the hazardous materials supply chain, including platforms, all modes of transport, chemical plants, terminals and storages. The results show that more than half (52.1%) of incidents are attributed to the transport system. The study largely considers incidents happening during maritime transport, which account for 18% of transport in cidents. In absolute terms, the FN curves of maritime transport human risks are generally found to be well below the corresponding FN curves of aggregated supply chain human risks.