Yes, conspiracy - there really is no other term for what has happened

Whether it began as a conspiracy or not, it has quite obviously been a massive conspiracy (or conspiracies) since it happened in order to cover up the extent of the spill, cover up the use of dispersants, cover up the extent of the dangers, limit liability and find ways to evilly profit while poisoning our gulf.

I agree with Griz - corporate money making antics are pretty much conspiracie by definition.  The same is true of coporate cover up antics.  When you conspire to make money or limit liabilty through fraud and deception, it is a conspiracy.  That is exactly what has happened - ergo, it is and has been a conspiracy.