ExxonMobil's 2008 profits, according to Fortune magazine: $40.6 billion dollars. That's profit, mind you, not total revenue; that was a bit under $373 billion.
2010 budget for the entire EPA: $10.5 billion.
I.e., if the EPA devoted itself entirely to policing this one oil company, ExxonMobil could outspend it three to one and still remain profitable.
Res ipsa loquitor.