I was reading some info on the level 4 protocols, and they use frequent washing of the protective gloves in bleach as they work on various samples containing Ebola, so Bleach must have some effect.
They also dress in space suit type outfits with injected air to breathe rather than depending on masks, and filtration devices, and several layers of gloves that are taped around the edges to the suit to create a sealed system.
I don’t think the hospital protocols are near as strict though, which may be why some health care workers have become infected.
That tells us even the best gloves won't keep it out. Several gloves is to give them extra barriers. A certain percent get past glove #1, then a percent of that gets past glove #2, and crossing your fingers that some smaller portion can only get through glove #3 and hopefully before it finds it's way through the last glove you've finished your task and are back in the decontamination room.