This lecture focuses on the essential safety protocols for handling dangerous chemicals in laboratory settings. It emphasizes the importance of understanding chemical waste, including the need to respect incompatibilities and reactivities. The instructor discusses the use of a separation tree to manage chemical waste effectively. Additionally, the lecture highlights the significance of studying every new situation and procedure to ensure safety. The content is aimed at promoting occupational safety and health within the School of Basic Sciences at EPFL, providing guidelines for safe practices when working with hazardous materials. The lecture also includes references to specific types of chemical waste, such as concentrated acids and special waste categories, underscoring the need for proper disposal methods. Overall, the lecture serves as a crucial resource for students and professionals in the field, reinforcing the importance of safety in chemical handling.