If methane is a concern for depleting oxygen levels in the ocean ... then the hexane version of glycol ether, 2-butoxyethanol that is 38-60% strong in the dispersants, even more so. Let's consider all the variables (trying to get rid of carbons and then adding a lot more on top?) Not to mention that it is yet unrealized that exposure to glycol ether causes flu symptoms (not a virus) and is a serious health risk to all! The autoimmune causing, cancer causing, birth defect causing chemical.

At a Congressional hearing, Representative Jerrold Nadler, a New York Democrat, said that the use of dispersants “could result in thousands and thousands of people getting sick or dying as a result of the cleanup, not of the original disaster.”

True

Methane adds Carbons to water / limits oxygen available to marine life / So do other glycol ethers
http://www.visionlearning.com/ library/module_viewer.php?mid= 60 Let's Learn about Organic Chemistry
chemical formula of methane  CH4
 
 
Chemical Formula. Structural Formula. 1, Meth, Methane, CH 4, CH4. 2, Eth, Ethane, C2H6, CH3CH3. 3, Prop, Propane, C3H8, CH3CH2CH3 ...
Carbon
Atoms

Prefix

Alkane
Name

Chemical
Formula

Structural
Formula

 aka
1 Meth Methane CH 4 CH4  
2 Eth Ethane C2H6 CH3CH3  
3 Prop Propane C3H8 CH3CH2CH3  
4 But Butane C4H10 CH3CH2CH2CH3  
5 Pent Pentane C5H12 CH3CH2CH2CH2CH3  
6 Hex Hexane C6H14 ... 2-butoxyethanol
7 Hept Heptane C7H16    
8 Oct Octane C8H18   2-2-butoxyethanol
9 Non Nonane C9H20    
10 Dec Decane C10H22    
 

C6H14O2 (2-butoxyethanol) such as in dispersants

adding a lot of carbons to the mix / oxygen depleting too?

 
The chemical formula for any alkane is given by the expression CnH2n+2. The structural formula, shown for the first five alkanes in the table, shows each carbon atom and the elements that are attached to it. This structural formula is important when we begin to discuss more complex hydrocarbons. The simple alkanes share many properties in common. All enter into combustion reactions with oxygen to produce carbon dioxide and water vapor.

What is glycol ether?  *   A pesticide, a teratogen, an organic solvent, a poison, a neurotoxin  *

http://www.valdezlink.com/same.htm

Not without research:  http://www.valdezlink.com/re/msn/renalliver/notwithout.htm  

http://cbs11tv.com/oilspill/oil.BP.methane.2.1759143.html