The safety of hydrogen is also critical, encompassing not only scientific and technological aspects but also psychological and societal issues. Despite its perceived reputation, hydrogen has an extraordinary safety record during many decades of use in industrial applications. However, hydrogen is significantly different from today's common fuels because of its ability to migrate through very small channels, and also in its combustion properties—again very different from carbon-based fuels. These aspects demand diverse safety precautions and an appropriate (new) culture for operations in which customers will interact directly with hydrogen and fuel cell technologies.