Injuries caused by products are often the result of a design defect, manufacturing defect, or inadequate warning about foreseeable risks. There is a duty on manufacturers to produce safe products, and to provide warnings about any risks associated with their use.
The design and manufacturing stages are usually the most important in terms of liability. If you can prove that the product was defective in its design, the company who designed it can be held liable. If you can show that the product was defective in its manufacturing process, then the company who manufactured it can be held liable. Manufacturers are responsible for providing safe products, but they are not responsible for accidents resulting from misuse or abuse of their products. Consumers also share some responsibility for using products in a safe manner.