The three companies involved in the Gulf of Mexico oil spill have blamed each other for the catastrophic explosion of the Deepwater Horizon oil rig.

As BP reveals expenses of $US350 million ($395.6 million) in containment efforts, relief well drilling, payments to Gulf Coast states, compensation claims and federal costs to date, a US Senate Energy Committee has also heard testimony from executives representing rig owner Transocean and contractor Halliburton.

BP is blaming the well’s eruption on a failed blowout operator, supposedly a “fail-safe device” in case of an accident. It claims Transocean is responsible for the operator.

Halliburton, which was contracted to provided special cement for the oil well, says it was “contractually obliged” to follow BP’s instructions.

For its part, Transocean says the failure of the blowout operator is immaterial, as drilling had been completed.

Insured losses from the oil spill enveloping the Gulf of Mexico are expected to reach $US1.5 billion ($1.65 billion). The Insurance Information Institute estimates insured losses at $US1.4 billion ($1.54 billion).

Transocean says the rig is insured for total loss coverage and wreck removal of $US560 million ($605.5 million).

Eleven crew members are still missing, presumed dead as the well leaks an estimated 5000 barrels of oil a day.