is there a website showing the fire safety codes?
Being that you says it's a powder it is likely (Sodium Bicarbonate) which is rated with a marking BC. This is not harmful as it's actually baking sodium, you can even consume it for heartburn. However, the fact that you are at a location that cooks it's much more likely it was an extinguisher of ABC which has Ammonium dihydrogen phosphate. It's used as it's much more effective in high heat such as grease fires. It's not toxic but if inhaled, it can cause nausea to the point of vomiting.
It's hard to properly diagnose from here. But i can say the engines oil pan does not like speed bumps. If your leaking a significant amount of oil, stop do not attempt to start or drive the car. The sound can be a broken suspension component, or in fact the engine that is now bone dry with no oil. Engine failure will cost several thousand to repair. Next time, keep an eye out for those bumps!
