re: BP didn't follow BOP law ... blaming MMS ... ?????

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then shouldn't there be a second set of shear rams

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pretty much all of the 15k psi rated subsea stacks do have 2 shear rams. this particular stack that the horizon was using featured two sets -- a cameron super-shear ram that is pretty much the most powerful shearing ram on the market and a blind shear ram. one thing to note, the super shear does not seal and hold pressure, the upper shear ram does. however, this is understood and is build into the emergency disconnect sequence. i do not know how their auto-shear sequence was set up.

in any case, the drill pipe that they would have had across the stack should have been easily shearable, as it was not an exotic grade of pipe like V-150. they had 6 5/8" in the string, but i can't imagine they had it across the stack, given that a 6 5/8" tooljoint won't fit inside the 9 7/8" casing they ran.

where shearability problems really come up is running casing -- as there are a number of sizes of casing that cannot be sheared. that's really where cameron's super-shear ram comes into play, as it can cut a lot of stuff conventional blind shear rams cannot.