Washington’s Blog 
May 17, 2010
Everyone knows that the dispersants being dumped into the Gulf oil are toxic. As I wrote  Friday:
Highly toxic dispersants have been used to try to break up the oil. See this  and this . Not only are dispersants being released underwater , but the air force  is also dropping dispersants on the slick from above.
The official information for the dispersant reveals  problems:
OSHA requires companies to make Material Safety Data Sheets, or MSDSs, available for any hazardous substances used in a workplace, and the ones for these dispersants both contain versions of a disturbing statement.
Both data sheets include the warning “human health hazards: acute.” The MSDS for Corexit 9527A [the dispersant apparently being used in the Gulf] states that “excessive exposure may cause central nervous system effects, nausea, vomiting, anesthetic or narcotic effects,” and “repeated or excessive exposure to butoxyethanol [an active ingredient] may cause injury to red blood cells (hemolysis), kidney or the liver.” It adds: “Prolonged and/or repeated exposure through inhalation or extensive skin contact with EGBE [butoxyethanol] may result in damage to the blood and kidneys.”
Indeed, the specific dispersant being used is more toxic and less effective  than other alternative dispersants, perhaps because of BP’s connections to the manufacturer.
In addition, new questions have arisen as to whether the dispersants might actually being increasing damage from the oil itself.
As the Christian Science Monitor notes today:
More relevant could be the dispersant that BP is applying  to the oil at the source. BP officials have hailed the process as a success, noting diminishing oil at the surface. But the dispersant breaks the oil into smaller drops, which might instead be spreading throughout the water column, instead of rising to the surface.
It is not clear what this would mean environmentally, though past research indicates that oil can be trapped in the seabed for decades  after oil on the surface is cleaned away.
Shouldn’t the use of dispersants be stopped until scientists figure out whether they will make things better or worse?