BP used the dispersants Corexit 9500 and 9527. These products are manufactured by Nalco. The exact chemical composition was considered proprietary, and was not made available to the public until early June 2010 despite concern from the medical and environmental communities.

The following is a list of chemicals found in Corexit 9500 and 9527, with links to their Material Safety Data Sheets (MSDS):

• 1,2-Propanediol (CAS Registry Number 57-55-6)
• Ethanol, 2-butoxy (CAS Registry Number 111-76-2)*
• Butanedioic acid, 2-sulfo-, 1,4-bis(2-ethylhexyl) ester, sodium salt (1:1) (CAS Registry Number 577-11-7)
• Sorbitan, mono-(9Z)-9-octadecenoate (CAS Registry Number 1338-43-8)
• Sorbitan, mono-(9Z)-9-octadecenoate, poly(oxy-1,2-ethanediyl) derivatives (CAS Registry Number 9005-65-6)
• Sorbitan, tri-(9Z)-9-octadecenoate, poly(oxy-1,2-ethanediyl) derivatives (CAS Registry Number 9005-70-3)
• 2-Propanol, 1-(2-butoxy-1-methylethoxy)- (CAS Registry Number 29911-28-2)
• Distillates (petroleum), hydrotreated light (CAS Registry Number 64742-47-8)

* A component of Corexit 9527 only.