Old oil drill/pump site

I have some land that was drilled for oil about 50 years ago. There is an asphalt like substance on parts of the land. I suspect it is old crude that spilled onto the dirt and has remained for ages. I have been told it is harmless but I can't say I believe that. Any suggestions about what to do to verify this or how to repair the site?

Check out the work of Paul Stamets. He has had excellent results remediating oil spills with woodchips and mushrooms. I would say pick up the visible crusts and dispose of them off-site, or use them for fuel, and then till in inoculated woodchips, and mulch more on top, of any areas you suspect might be contaminated. Irrigation in dry spells is probably necessary. You might soil test any areas you want to grow food on and locate some "clean" spots for this purpose early on, too.....

It's almost certainly not crude, but rather actually is asphalt. It's really common that they'll spray it down on the ground around tanks and the like to prevent spills from contaminating the groundwater. I'd tear it up and look into getting it disposed of.

What state are you living in? Here in Oklahoma all you have to do is pick up the phone and call OERB and they'll send a crew out to clean it up and seal the well permanently. I would suspect (read: hope) most oil producing states have a similar deal. I don't have any well sites on my land but they just did one on the next lot over and they did an amazing job, left it completely clean, regraded it with new soil and even planted a bunch of trees. I saw them come out several times over the next year to do follow-on soil testing and to make sure the treatment took hold. Cost to land owner: $0

I live in Southeastern Illinois, just outside of Keensburg, an old oil mining town. I think it is crude oil soaked into the ground. The soil here is sandy and this stuff has no rock in it, just sand. This stuff does burn. After it gets hot and starts glowing red it will break up into fine particles. It will not burn without a hot flame getting it real hot. When the flame from this stuff burning starts to die down, if you break it up it will flame up again for a while. After it burns it is brown like dirt. I think the well itself has been sealed because there is a 4' cube of cement on the site. I don't think Illinois is set up as easy as Oklahoma for fixing this mess.

Should have mentioned that I used to work in a refinery. How deep does it go into the ground? I've never seen crude oil spills that old, but what I've seen gets kinda gummy rather than hard. I suppose after a long enough time it could, but I've never seen that.

They spray down pitch (as in the bottom draw from a vacuum distillation column) on the ground. It's like road asphalt without the aggregate. If just one coat, maybe a quarter inch thick, but if the well was active for some time, they probably would have put down more than one layer, and it could be quite thick.

This stuff varies from just a few inches thick to a foot thick. Some of it has enough soil on top of it now to grow grass, other places it protrudes from the ground in patches. Being inactive for so long do you think it has rendered itself harmless even though with enough heat it will burn? When it first catches it will burn by itself with a yellow flame, if you pull it out of the fire. I was told the well has been inactive for about 50 years and the concrete block on top of the well head (i am guessing about the purpose of the concrete) is very very weathered.

Either way it could be high in heavy metals, also some crudes have cyanide compounds in them. Different fields have different little quirks like that. I'm not really familiar with the characteristics of Illinois crudes, although 50 years back they tended to really only go for high quality crude oils, so the chances of getting too many heavy metals, cyanide compounds (which can wrek havoc on refining equipment), etc. are pretty slim.

Any hydrocarbons that would be dangerous (Benzene and the like) would likely have left long ago leaving you with just the heavy stuff you're seeing now. If it burns fairly cleanly that would be a reasonable way to get rid of it, but you'd have to do something with the ash, and that's certainly not something I'd like spread on my garden. If there is no services in Illinois for restoring old well sites, you're likely stuck with hauling it off yourself.