It is generally appropriate to file a third-party construction accident lawsuit when the liable party is not your employer. If a negligent third party caused your injuries, you may need to file a lawsuit. Some circumstances that may warrant a third-party lawsuit are: Defective protective equipment contributing to your injuries Scaffolding collapsing because of defective design A third-party contractor making decisions that lead to your injuries A third-party motorist driving into the construction scene, causing a collision that leads to your injuries An attorney will evaluate your unique circumstances and provide legal advice on how you should pursue compensation for your losses.