It depends on how the accident happens and how your company treats an accident.
For example, if the accident happens during a construction project, on site (let's say that a tower crane falls on the side of the building and destroys a part of it), then it's definitely a direct cost.
If you are working on a web development project and one of the server goes down and needs to be replaced, then it might be a direct or an indirect cost. It is a direct cost if the server is dedicated to the project, and indirect if not. Additionally, even if the server is dedicated for the project, then it might also be an indirect cost in case the company wants to use the server for future projects.
Another example is let's say that during a web development project, one of your resources misses two weeks of work for one reason or the other. If you hire a resource to temporarily replace the original resource, then it can be an indirect cost in some organizational structures (functional, some matrix org structures), while a direct cost in other organizational structures (projectized).