Updated

EPA officials say their first round of testing on chemicals used to break apart the oil in the Gulf of Mexico shows all the available dispersants are generally equally toxic.

Paul Anastas, EPA's assistant administrator for research and development, said Wednesday that the testing also showed the chemicals are far less toxic than oil. He said none of the chemicals had dangerous effects on the sea life tested.

The chemicals break oil into smaller particles that are easier for microbes to consume.

Anastas says the chemicals break down in weeks or months, while it takes oil years to biodegrade.

However, he cautioned that more testing was needed to study how toxic the dispersants are when mixed with oil. This round of testing only studied the chemicals not mixed with oil.