W123, USED Mechanical

I recently parked my car on a steep hill with the passenger side downhill. When I returned to my car there was fuel leaking down the street and inside the wheel well in the trunk. I unclogged the rubber piece that lets water out of the trunk and drained the fuel out. I use biodiesel and I don't see any worn through parts. Any idea how the fuel got into the trunk, all seems normal now but I wanted to make sure there weren't any safety issues.