Open Source is a winning solution for many industries already - and now even safety critical applications want to make use of it. While “security” is a capability of open source since many years, a few years ago using open source in safety critical applications seemed to be impossible even to think about. Nowadays it has become a valid option for upcoming applications. This kind of application that should save lives, or at least not harm anyone. However, with advancements in technology and safety integrity standards, open source is becoming a valid option for upcoming safety critical applications. This talk will provide an overview of how open source projects approach their integration to safety critical applications. Depending on the expectations of these applications, there are different solutions to address their needs. The talk will introduce example projects such as ELISA, the Zephyr Project, and the Xen Project, which are currently addressing these expectations with various mechanisms and approaches.