False Positive Circumstances

As a vessel travels through a slick of spilled oil, its wake can produce a swath of clear water, either by physically parting the oil or by mechanically dispersing it (by breaking it up into small droplets). Such a swath of clear water behind a dispersant application vessel (as is visible in the photo below) can give the appearance that the dispersant is working (that is, a "false positive"). However, unlike chemically dispersed oil, mechanically dispersed oil eventually will recoalesce and float to the surface.

(09.01.79, Unknown)