Two Obama administration officials confirmed the order Thursday. Some lawmakers and environmental groups have criticized use of the dispersants, which shoot chemicals thousands of feet beneath the sea. The chemicals break apart the oil and keep it from reaching the surface.
Safety data documents show that one of the chief agents being used, called Corexit 9500, is identified as a "moderate" human health hazard that can cause eye, skin or respiratory irritation with prolonged exposure.
A spokeswoman for the EPA declined immediate comment.