The massive oil spill resulting from the April 20th explosion on the Deepwater Horizon oil rig is the largest oil spill in history.  It's estimated that somewhere close to 300,000,000 (300 million) gallons of oil were released into the Gulf along with approximately 1,000,000,000 gallons of a toxic dispersant known as Corexit®.  BP's own worse case scenario suggests the total oil released could be as high as 500,000,000 (500 million) gallons.  
 
The impact on various species of fish, seafood, wildlife, etc. is likely to be devastating. The  impact on human health is likely to be variable.  Those people with pre-existing health problems are likely to be most effected, especially those with pre-existing metal and chemical poisoning,  nutritional deficiencies,  metabolic and endocrine (thyroid and adrenal) problems and persons with nervous system and immune system problems.   I would not be surprised to see a marked increase in chronic fatigue and fibromyalgia, Candida, Epstein Barr Virus,  mycobacterial, and other chronic infections  as well as people with symptoms resembling Gulf War Syndrome.
 
We know that a large proportion of our population has already been chronically exposed to heavy metals  and toxic chemicals as a result of preexisting environmental pollution.  An inexpensive way to determine susceptibility to oil and chemical exposure from the BP oil spill is to have a hair analysis performed.  Those people with inability to detoxify and excrete chemicals  (and metals)  will be seen to have trace mineral derangement. (See why hair analysis is used for optimal management of detoxification) These are the people at maximum risk since their detoxification and excretion pathways are dysfunctional. Such individuals will benefit from oral chelation and detoxification therapy which can restore their detoxification and excretion pathways.  Successful regimens will require dietary and other lifestyle changes along with appropriate supplements and an individually designed  approach.