Dispersants

Sometimes the cure is as bad as the disease

But BP spokeswoman Marti Powers told CNN the tests near the wellhead were successful and large amounts of the chemical will be dispensed Saturday. These types of tests have never been done before, Powers said.

The dispersants, she said, attach themselves to underwater concentrations of oil, causing the oil to sink to the bottom and dissipate.

While the dispersants can help dissipate oil slicks and help birds and other land-based or water-surface wildlife, the chemicals can hurt fish and other underwater species, environmentalist Charter said.

"The scale of the event and the likely duration of the event ... really leaves responders with no good options," Charter said. "While [dispersants] can protect terrestial wildlife ... out in the ocean they make toxic biocomponents available to the marine food chain."