Are these concerns unfounded? Well, yes they are but I understand where you are coming from. Have you ever heard of anyone getting sick because they use their trailers as they were designed to be used? Anyone? And, there must be millions out there.
Do you know anyone who has a septic system at their home? Do they get sick because of the bacteria somehow gets airborne and invades their home? The Gray tank is basically filled with sink water. You use your sinks daily and a lot of this stuff is held in the P traps. Have you heard of anyone getting sick because this bacteria laden water somehow gets airborne and infects everyone in the house?
There are chemical additives for your black tank to take care of these issues. When used as per manufacturer recommendation they are perfectly safe. Same goes for your gray tank and with proper care and maintenance you will be totally safe.
