Now that the Coast Guard has officially called off its search efforts for the 11 offshore workers who went missing after the Transocean rig exploded off the Louisiana coast, investigations will begin in earnest into what is being described as the deadliest offshore disaster in decades.

A lot of attention has been focused on whether the explosion occurred because of a blowout. Such blowouts are not uncommon on oil rigs, but the situation and circumstances in which the Transocean rig Deepwater Horizon exploded, were different. The semisubmersible rig had been done with most of the drilling, and had been close to abandoning the gas well when the explosion occurred.  It is uncommon for an explosion to occur at this point in a rig’s drilling operations.

The investigations will largely focus on mechanical failure and human error. Mechanical malfunctioning of rig equipment is not a very common occurrence, as there have been major strides made in equipment safety. Investigations are likely to focus harder on human error as a contributing factor in this disaster.

A number of investigations have begun, or will begin soon. The Coast Guard is conducting its own investigation, and the Interior Department through the Minerals and Management Service will also conduct an in-depth probe. Meanwhile, a Houston-based firm that manufactured the blowout preventer used on the rig, is also working together with Transocean and BP to determine what caused the explosion. Besides, insurance companies and Texas offshore injury attorneys will also begin their investigations to find out the cause of the explosion.