This is a massive catastrophe with huge consequences, and the best you can come up with is three vaguely poetic paragraphs about how oil kills shrimp hearts [Dear Science, May 13]. How sad. I couldn't help thinking it sounded just like the crap Charles spews.

How about something useful? Tell us a little about how the dispersants work and whether they're a good idea or not. Tell us how it happened (as much as we know for now) and how to avoid things like this in the future. Tell us something useful instead of a Mudede-style philosophy rant.

You Can Do Better

So begins part two of Science's oil-spill-o-rama: the chemistry of what's happening. (You must excuse a bit of philosophical mournfulness in the last column. I study living things as a profession; my first reaction was abhorrence of the whole escapade.)

Chemically, oils are chains of carbon and hydrogen. These sorts of molecules are nonpolar—the electrons and atoms symmetrically shared throughout. In contrast, water is polar—the electrons favor the oxygen over the hydrogen in good old H20. Like favors like, when it comes to polar versus nonpolar molecules. The slightly unbalanced charges in water molecules want to spoon up with other polar molecules and atoms (other water molecules, salts, short acids, alcohols, and so on). Nonpolar molecules find all these imbalances irritating. Why can't everyone just be bland? The net result is oils segregate out from the polar water. This is why oil-based salad dressings and natural peanut butter separate. The same thing is going on with the oil slick.

Dispersants work as emulsifiers. Emulsifiers are just molecules with both polar and nonpolar parts attached to one another. The polar head of the emulsifier plays nicely with the water; the nonpolar tail sedately makes friends with the oil. Oil-spill emulsifiers work the same way as the chemicals added to industrial-grade peanut butter to keep it mixed. The gigantic sheets of oil are broken down into microscopic droplets and "disappear." The oil is still there, it's just too small to see. Over a much longer time scale, rough seas and waves can also break the oil into tiny droplets (like one hell of a salad-dressing shaking). Neither step solves the underlying problem—the release of persistent (nonpolar) organic pollutants into the biosphere.

As far as why this happened, nobody really knows just yet. The explosion was potentially caused by an unexpected pocket of natural gas being released by the aggressive drilling, exploding on the surface. The rig's well lacked basic automatic shutoff valves (cheap, effective, and not required by industry-written regulations). Given the sheer volume of oil consumed on a daily basis, it's striking how infrequently disasters of this magnitude occur.

Emulsifyingly Yours,