Substance to absorb oil remaining in U/G tank?
October 19, 2010 11:33 AM   Subscribe

Oil Tank decommissioning. Some residual oil left in underground tank. Anything I can put in there to absorb this?

I've finally switched to gas, as the cost of an oil fired heating system was prohibitive. I had about 100 gallons remaining in the tank, which I had drained out by a local charity. However, they leave a residual amount in there as they don't want the sediment at the bottom. There may be as much as 30 gallons in there. The tank is underground, and I can't afford the decommissioning costs at the moment, though I will get it done in future. It's also upward of 30 years old and definitely end-of-life for a steel tank, but core samples around in indicate it's still intact. Cleaning up a spill can be ruinously expensive (I'm in Portland, OR), so is there a substance I can put in the tank to absorb this excess oil so that if it does decay in the coming years, any leaks would be mitigated?
posted by nicktf to Home & Garden (6 answers total) 3 users marked this as a favorite
I googled "oil absorbent" and came up with a bunch of hits, including for this company, who sells oil absorbent mats and other materials.

Also, I'm in Portland, and we just had an oil tank decommissioned as part of buying a house here. I have no information because of this, but I feel compelled to mention it.

Good luck.
posted by bluedaisy at 11:41 AM on October 19, 2010

Hi! I work for a heating oil company! The answer to your question: No. Some companies will come vacuum out the tank, but that costs money, too. I'd suggest you speak to your local municipality, if you already haven't, to find out what you need to do to close the tank. Some places don't require you to removed the tank completely, just vacuum out the oil/sediment and fill it with foam or sand. However, there is nothing you can put in the tank to make the oil go away or be spill-proof.

On preview: Oil absorbent is mainly for easy clean up (for spills above ground and/or in houses) and does not prevent the oil from being dangerous to the surrounding soil. It would still be a huge problem for you if the tank failed in the future.
posted by two lights above the sea at 11:51 AM on October 19, 2010 [2 favorites]

I have a call in to someone in my town who is making a few calls to find out who in Portland might do it. If he comes through, I will post below (I have to leave my desk right now).

You also have to know that empty oil tanks, when left in the ground, have a tendency to float up to the surface if not well fastened down. Especially in a place with a high water table in the Winter.
posted by Danf at 12:06 PM on October 19, 2010

First thing you'll want to do is remove as much liquid as possible. 30 gallons of fuel oil is a pretty nasty clean up if your tank develops a leak; something that is likely now that the oil isn't being stirred up so any moisture in the tank will migrate to the bottom and rust it out.

You can get the vast majority our with a piece of copper tubing, a few 5 gallon buckets with lids, and a simple hand pump. large tubing will transfer faster and small tubing will leave less in the tank when vacuum from the pump breaks. If you are mechanically inclined there is a way to do this using the vacuum from a car engine.

Once you have as much oil removed as you can with a pump then you can repeatedly add simple kitty litter to the tank and then vacuum it out with a shop vac.

Taking these steps will prevent a huge disaster when your tank fails. You still want to get that tank out of there as soon as possible. Unless your jurisdiction requires some sort of certification to remove the tank simple shovels, a chain and a pick up can get the tank out of the ground.

Before you start though it would be a good idea to look into disposal options in your area; they might have specific requirements on absorbents. The tank it self could be tricky to get rid of too. Scrap yards here require the tank to be cut up before they'll take it and that has to be done by hand to minimize sparking.
posted by Mitheral at 1:36 PM on October 19, 2010

Decommissioning an oil tank is not a do-it-yourself operation in Portland. When the time comes to sell your house, you will need to provide the buyer documentation that the tank was decommissioned by a licensed outfit.

When we sold our house in Portland, we had to get the old oil tank decommissioned. This involved having official soil samples from either end of the tank being sent to an approved lab to prove that the tank had not leaked. The decommissioners drained the oil, cut off the fill and vent tubes, opened up the top of the tank, sent some poor guy inside to wipe out the residual oil, then filled the whole tank with pea gravel, and finally filled in the hole in the lawn. This cost about $3000 for a non-leaking tank.

The cost to decommission a leaking tank could be $10,000 or more, since contaminated soil must be taken away and replaced with clean soil for as far as the plume of leaking oil extends. The longer you leave an abandoned tank without fully decommissioning it the greater the chance of a leak.
posted by monotreme at 3:18 PM on October 19, 2010

It looks like homeowners can decommission their own heating oil tanks in Oregon, though I wouldn't recommend it. The regulations can be difficult to navigate, and you'll need to ensure you're complying with federal, state, and local laws, not to mention the safety hazards. I'm not entirely familiar with Oregon regulations, but as far as I can tell, the Oregon Department of Environmental Quality (ODEQ) permits heating oil tanks and you'll need to report your decommissioning activities to them, which will include the oil removal you've already done, so keep good records. The ODEQ has a lot of guidance documents for homeowners on their website, including decommissioning guidance, reporting guidance, and a list of ODEQ-licensed contractors. I know you don't want to shell out for the entire decommissioning procedure right now, but, at a minimum, I think it would be wise to have a contractor remove the remaining oil and rinse your tank at this time. The ODEQ generally requires that underground storage tanks that are no longer in use be removed within 30 days, but I'm not sure if this applies to residential heating oil tanks.

If you really can't do any of that at this time, then I'd do as Mitheral recommends and remove as much oil as possible, then use kitty litter to soak up the residual. You'll have to find a disposal facility not only for the oil, but for the absorbent as well.

You can also call the ODEQ for guidance. They're generally pretty reasonable if you're trying to do the right thing. And you can always call anonymously and ask hypothetical questions.

And like everyone else already said, the sooner you decommission it, the better.
posted by curie at 4:22 PM on October 19, 2010 [1 favorite]

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