Hi @David Chwaszczewski. In the past, when I've done this, I'd called the EPA and was told they don't regulation residential fuel oil tanks. I contacted a local fuel oil supplier, who charged me $200 to pump out whatever was in the tank, figure out what was in there, and haul it off. They then filled the tank with sand and cut off the risers. That was that. Oh, and they reimbursed me about $75 for the usable fuel oil that they'd pumped out. Not a bad deal.
This time, I skipped the EPA and contacted fuel oil suppliers, and one after the other said they didn't do it that way anymore. They suggested I call a company called SafetyKleen. SafetyKleen would charge me nearly $1200 just to test the contents, the results of which test would take 2+ weeks to receive. Then, they would charge another $1500 or so to pump out the contents, dig up the tank, run soil analyses, etc. Hauling off and disposing of the contents was an entirely different step and would cost $900+, depending on if soil was found to be contaminated. Hauling off the tank is another step and another cost.
I ended up buying a pump and some tanks, pumped out the fuel oil myself and gave it to a guy who uses it to heat his workshop. My grading contractor will gently dig up the tank, and one of my workers wants to keep the tank to turn it into a smoker/grill. If we find any oil has leaked into the soil, my grading contractor will carefully dig it up and dispose of it separately at the proper local facility for a nominal fee. So, all totaled, my expenses were about $900 for the pump and tanks (which I'm sure we'll use again) plus $350 labor for the guys who did all the pumping and hauling. My grading contractor will already be onsite, grading the entire property, so he's not charging me extra.
I'm always careful not to contribute to any existing pollution problems, but I'm also not interested in blowing a potential $5000 when I was able to find an alternative and safe and less expensive solution.