Local Mechanic????
It's going to be a "Poltergeist" experience for them. I don't see how they can get away with that. I can see it now in the advertisements "Beautiful New Homes with breathtaking views, placed in the hills of Vallejo on top of some dead people, gauranteed to give you a great garden from all the natural fertilizer". I worked on base along with both my parents, and alot of friends. Any time you build on a former military installation the soil is going to be harmful. Wait till the people's kids start having health issues, and then the lawsuits will roll in.