The spill was also notable for the volume of Corexit oil dispersant used and for application methods that were "purely experimental."[116] Altogether, 1.84×10^6 US gal (7,000 m3) of dispersants were used; of this 771,000 US gal (2,920 m3) were released at the wellhead.[13] Subsea injection had never previously been tried but due to the spill's unprecedented nature BP together with USCG and EPA decided to use it.[126] Over 400 sorties were flown to release the product.[116] Although usage of dispersants was described as "the most effective and fast moving tool for minimizing shoreline impact",[116] the approach continues to be investigated.[127][128][129]