You don't want tampons, butt wipes, cleaning chemicals, etc. entering your septic system.

As we walked into the first entrance my wife and I were hit with the strong smell of cigar smoke mixed with unknown chemicals.

These usually run closer to $1-$1.5k.I always recommend installing a laundry chemical dispenser at the site as well, with single-use size refills. 

I would figure out who the current chemical supplier is and who the rep is if they have one.

Our area has a huge chemical plant industry where I believe almost anything could work in terms of real estate options. 

They were set up like that because of the a large number of out of town people that come here to work in the local chemical plants.

My difficult position is that I am currently unemployed, though I work as a contract electrician in chemical plants, I’m usually unemployed a few times a year, though make consistent yearly salary.I recently went into a lease option deal on a duplex, valued at 275k.

There's some nasty chemicals used in meth manufacturing.  

My current occupation is a chemical sales engineer.

And good advice on the oily rags- the drying agent chemicals in wood finish oils produce an exothermic reaction (they give off heat).