What safety protection do you need to enter in the engine room during running condition of plant?

If you're about to go near any type of engine, wether it be a small V4, or a Rolls Royce 777 jet engine, ear and eye protection is highly recommended, sometimes neccessary. A hard hat and a high-visibilty jacket is a good idea too. Latex and work gloves are a good idea too, as they keep your hands clean and not slippery, and reduce the chance on major injury to them. Work boots should be worn too.