I've run into unauthorized dumps before. They can be a nightmare. The City Engineer of one of our client cities used to jokingly hate me, because I would walk across City land and 55 gallon drums would spring to the surface. /forums/images/graemlins/blush.gif
If you want the stuff analyzed, you need an environmental laboratory. If you can’t find one in the phone book, call a local geotechnical or soil boring firm. They often do hazwaste sites, and can recommend a good lab. They may even have their own lab. Talk to the lab and work out what minimum tests you need to do.
Now hang onto your hat. The last time I had hazwaste lab work done, it was about $1,200 per sample! The usual test panel is for heavy metals, pesticides, and organic chemicals.
If your stuff passes, then it can be disposed of in any landfill. You may need copies of the test results if the landfill operator challenges you. If it shows up as hazardous, you’re screwed. You now own the Love Canal. If it’s hazwaste, plan on cleanup and disposal costs of at least six digits. You cannot escape this liability by selling your property. For this reason, you may want to have your attorney submit the samples, thereby providing a blind address and giving you breathing room until you figure out what is up. Be sure your attorney talks to the lab first, and does the Chain of Custody paperwork correctly, or you may have peed away the money for the first tests and need to have the tests re-done to make them legal. That's an easy requirement to get right, but it must be done right.
I’d want to proceed very cautiously here. If you send up a rocket, people with suits and clipboards will fall out of the sky on you. OTOH, the stuff could be killing you.
If you have hazwaste, then the Federal provisions of CERCLA, The Comprehensive Environmental Response, Compensation, and Liability Act, come into play. This is the stuff that puts whole villages of lawyers’ kids through college. The good news is that the previous owner, and the one previous to him, if he placed the waste, all the way back to Adam, is still on the hook. Everyone who ever handled the waste is probably on the hook, including the brother in law whose wheelbarrow was stolen to move it. It’s called strict joint and several liability. It’s a big hook with numerous barbs. The bad news is that you are on the hook unless you can get off. There is an “innocent landowner defense,” that may help you.
The usual procedure in these cases, is to try to find someone in the chain with deep pockets.
This is not good news, unless you can figure out yourself that the stuff is harmless (e.g. old fireplace ashes) and you can make it go away without sending up any rockets.