Faced with limited data, we've been careful not to attribute a causal relationship between dispersant use and illness in cleanup workers. But McClatchy notes that the dispersants' toxins may be making their way into the air that workers are breathing. Air sampling data gathered to ensure the safety of cleanup workers has identified a chemical compound in the air that is also in the dispersants BP is applying to the Gulf:

Little-noticed data posted on BP's website and the Deepwater Horizon site show that 32 air samples taken near workers have indicated the presence of butoxyethanol, a component listed as present in an oil spill dispersant used by BP, known as Corexit. The Environmental Protection Agency considers it toxic.

The BP document said the data demonstrates "that there are no significant exposures occurring." OSHA is monitoring the data and has said the workers haven't been exposed to harmful levels.

Here's what we've noted about this compound, 2-butoxyethanol:

The exact makeup of the dispersants is kept secret under competitive trade laws, but a worker safety sheet for one product, called Corexit, says it includes 2-butoxyethanol, a compound associated with headaches, vomiting and reproductive problems at high doses.

Last month the EPA ordered BP to switch to a less toxic dispersant. After BP told the EPA that it couldn't find one in the necessary quantities, the EPA said it would continue working with BP to find a suitable alternative. So far, that has not been accomplished.

In the meantime, cleanup workers have been getting sick. Between the Coast Guard and BP, possible explanations for this sickness have ranged from heat and fatigue to food poisoning.

BP has not yet responded to our questions about the status of the dispersant search or about what protective equipment it provides for cleanup workers.