The introduction of a new, powerful, mechanical home-use tool carries with it a high risk of product liability. This liability stems from both planned and unanticipated use of the product. In view of this, it is imperative that designers and manufacturers carefully analyze their proposed product to insure that possible failures and hazards have been evaluated and corrected, that current ergonomic principles have been used in the design, that instructions and warning signs clearly document the hazards associated with use of the product, and that the advertising describe only safe methods of handling and using the product. This paper describes the analyses that were performed on a tool prior to its production. The purpose of the analyses was to identify and solve as many of the hazardous operating problems of the tool as possible. To this end, a series of system safety analyses was performed to define the user, user-machine interface, and mechanical problems associated with the ditcher-saw.