This matter of abandoned, leaking wells briefly came to light during the height of the BP spill cleanup. An investigation by the Associated Press revealed a stunning 27,000 abandoned wells deep beneath the surface of the Gulf of Mexico. Over 4,000 of those had been improperly or "temporarily" sealed since the 1940s. Do these have a significant risk of blowing? Either way, word of the possibility passed like a blip on a radar screen. But it turns out that the AP report only scratched the surface -- there are far, far more abandoned wells that may pose a risk of leaking or blowing than those uncovered in the Gulf.

Since 1849, at least 2.5 million oil wells have been sealed up and abandoned by oil companies in the United States. And that's a conservative estimate, the one that's on the books of the oil industry's own trade group, the American Petroleum Institute. The real number could be even higher. Plugging up oil wells and leaving them behind is common practice for corporations-- after a well dries up, becomes unprofitable, or they run into legal trouble with it, they seal it up with cement, cover it up, and leave it behind.

Making matters worse, the EPA estimates that a full 17% of those abandoned wells have been improperly sealed, which means that there are some 425,000 wells that are likely leaking oil as you're reading this. Over time, even the seals on the properly sealed wells erode, due to exposure to environmental factors. Wind, rain, and sunlight beat down on them and crack them open. Leaks frequently appear in previously-sealed onshore and abandoned offshore wells, too. Unfortunately, most of these incidents happen out of the public eye -- or seem to be, if the media doesn't pick up on them.

The difference is that offshore wells, like the Macondo well from the BP spill, are drilled at much greater depths, where the pressure is much more intense and the likelihood of a cataclysmic link is greater.

The Risks

We've already seen what a full-scale offshore oil disaster looks like: lives lost in violent explosions, thousands of square miles of ruined environment, a vast amount of dead sea life, and coastal residents getting seriously sick from the toxic fumes that drift inland from the spill. (WWL-TV in New Orleans reported that toxic gases such as Hydrogen Sulfide and Methylene Chloride had been found by scientists studying Louisiana air.)

So now, imagine approximately 425,000 similar scenarios taking place on a much smaller scale. It's still pretty horrifying -- leaking oil kills fish and wildlife, and poisons the air and nearby water supplies. There might not be dramatic explosions rocking the sky (though sometimes there are), but there's still a very real danger to human health. The scientists studying the toxic gases in Louisiana said they could be more deadly than the spill itself.

Clearly, the biggest risk is still the fact that some of these wells lingering outside the public eye could blow. Of the thousands at risk of blowing, the greatest threat comes from the ones that were only supposed to be "temporarily abandoned" and therefore are not securely sealed. You would think this would make a pretty good case for motivating the supervising agency to do their duty and keep tabs on the oil company.

You'd be wrong.

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