How buyer write an oil tank contigency?

[David Smith]

The property has underground oil tank, till now, working and providing heat. 

Will do soil test.  But winter is coming.  I plan to remove it and replace it with gas heating in next spring.  

How to protect myself as buyers?

How much it costs to replace with gas heating?

[Mike McCarthy]

In NJ, you need to be really careful with underground oil tanks.

You'll need to have the soil tested. Most companies won't do pressure tests anymore since they can make a leaky tank worse.

If you get a clean soil test, get oil tank insurance from a local oil provider. It will help when you do remove the tank if you do run into any problems.

If there's any way to get the seller to remove the tank. I would probably have them remove it and replace it with an above ground tank and pay for it at closing. Even if you switch to gas, it'll be a good $1-2K investment.

Cleanup ranges from about $6K to 50+K. My parents went through about a $70K cleanup when they sold their house (luckily homeowners insurance covered it by some miracle.)
Another friend in NJ went through a cleanup after they bought a house. They actually dug under the house and under a neighbors house to excavate the contaminated dirt.

I think it's all overdone... but I'm not the one who has to get the EPA to sign off.