This is an update from the joint hearings by the Coast Guard and the Bureau of Ocean Energy Management, Regulation and Enforcement investigating the causes of the Deepwater Horizon oil rig explosion on April 20.

After BP and Halliburton officials argued about the use of key pieces of oil well safety equipment called centralizers, it turns out additional centralizers were ready on the Deepwater Horizon rig but simply weren't installed.

Centralizers are devices that are supposed to keep tubes in place in an oil well so cement seals can set evenly on either side. E-mails released in June by a congressional committee showed that Halliburton recommended using more than 20 centralizers to make sure the cement seal was good, but BP officials settled on just six of the devices to save time and money.

But in front of a Marine Board investigative panel Monday, the contract worker in charge of installing well casing and other tools testified that he only installed "four or five" centralizers and additional ones were delivered and never used.

"They did order some more and talked about getting them out there," said Lance John, a rig system specialist for contractor Weatherford. "Additional centralizers were delivered, but there were four or five run in the hole."

Asked if the other centralizers were made available to the rig but simply weren't used, John said, "Yes."

Read more: http://www.nola.com/news/gulf-oil-spill/in...