Even if the storm does not hit the area directly, it could affect the effort to contain the oil and clean it up. Hurricane Alex stayed 500 miles away last month, yet skimming in Alabama, Mississippi and Florida was curtailed for nearly a week.

The relief tunnel extends about two miles under the seabed and is about 50 to 60 feet vertically and four feet horizontally from the ruptured well. BP plans to insert a final string of casing, or drilling pipe, cement it into place, and give it up to a week to set, before attempting to punch through to the blown-out well and kill it.

BP's broken well spewed somewhere between 94 million and 184 million gallons into the Gulf before the cap was attached. The crisis - the biggest offshore oil spill in U.S. history - unfolded after the BP-leased Deepwater Horizon rig exploded April 20, killing 11 workers.

The cause of the blast is still under investigation, but there have been repeated questions raised by rig workers over the equipment and safety conditions aboard the rig. The New York Times reported early Thursday that rig workers said in a confidential survey before the April 20 explosion that they were concerned about safety and the condition of some equipment on board.

The Times reported that another report conducted for Transocean by Lloyd's Register Group found that several pieces of equipment - including the rams in the failed blowout preventer on the well head - had not been inspected since 2000, despite guidelines calling for inspection every three to five years. Transocean said most of the equipment was minor and the blowout preventer was inspected by manufacturer guidelines.

A spokesman for Transocean, the owner of the rig leased by BP, confirmed the existence of the reports to The Associated Press.

"As part of Transocean's unwavering commitment to safety and rigorous maintenance discipline on all our rigs, we proactively commissioned the safety survey and the rig assessment review," Transocean spokesman Lou Colasuonno said in an e-mail early Thursday. "A fair reading of those detailed third-party reviews indicates clearly that while certain areas could be enhanced, overall rig maintenance met or exceeded regulatory and industry standards and the Deepwater Horizon's safety management was strong and a culture of safety was robust on board the rig."