Still safe to drive? It fell off from the spot pictured.

 

The car is still safe to drive yes. That is basically just a splash shield that is there to keep road dirt and whatnot from splashing up inside your engine bay and getting onto all the components within. Ideally you should replace it or install a new one whenever possible, but you’re not going to break down tomorrow or anything like that and everything under your hood is designed to withstand some amount of water. What I would make sure to do until if/when you replace the shield is periodically clean your engine bay to keep dirt and road grime from building up on things and prevent rust as much as possible. The biggest concern I would have above all else honestly is premature oxidation/rusting due to the excess moisture getting on various components. Other than that it really won’t cause you any issues.