With each passing year, the public expects more of schools and teachers. Curricula become more complex, student populations become more diverse, responsibilities are added, and, except for resources, very little is taken away. Fundamentally, teachers are held responsible for everyone and everything that goes on in their classrooms, an awesome responsibility--and a world of opportunity. As classroom teachers and science teachers, they need to consider safety as broadly as possible. Investigative science activities usually generate more excitement and more physical movement than most other activities, so it's best to avoid adding adult or student guests to these activities. Since teachers are responsible for the safety of everyone present during laboratory investigations, they have the right to insist everyone acknowledge and comply with all safety procedures prior to joining or observing their class. In today's litigious society, they cannot prevent a lawsuit from being filed. No matter how unreasonable the complaint, the legal system provides the opportunity for people to take their grievances to court. Well-insured schools may be viewed as sources of "deep pockets" and targets of frivolous suits. Many things teachers can do to prevent being found at fault or liable are discussed.