In order to safely work with chemical and other hazardous materials in a laboratory, it is necessary to do some pre-planning before conducting experiments. Understanding the hazards of the materials, equipment, and what things could go wrong if not addressed in advance is key to practicing safe science in the lab. National Academies Press Prudent Practices 2011 suggests that lab workers ask themselves a hypothetical question before starting lab work: “What would happen if…?”, suggests they consider the possible contingencies and make preparations to take appropriate emergency actions. The authors provide the examples of loss of electrical power or water pressure but these are examples only and there are many possible scenarios that the lab worker should think about before beginning work with chemicals or other hazardous materials. Planning should include not only emergency planning but planning control methods to reduce risk of exposure to materials hazards to the worker doing the experiment and to others in the lab space.