iF YOU HAVE TO WORK AROUND THE bLACK wATER DISCHARGE AREA
make sure that you flush the tank out and refill it with a bleach solution.
Use gloves and appropriate body cover,plus a full face mask.
I flushed mine and was working under the unit removing the valves and pipes and a bit of dripping fell on my forehead.
A few days later I became very ill. and on my forehead and the eye brows scabs and pimples appeared. the doctors said I had Shingles, and said all would be well. I was medicated. IT DID NOT GO AWAY. later they said it was something else, but did not know what.
I was ill all summer. Finally it calmed down and I was applying Lamasil. It helped, but to this day I get flair ups and irritation.
FORE WARNED SHOULD BE ENOUGH.
Best of luck