BEAUMONT, Texas (AP) — Hurricane Gustav may trigger insurance claims as high as $10 billion including damage to oil facilities, according to risk management firms that issued preliminary estimates a day after the storm struck Louisiana.

While Gustav’s force paled in comparison to Hurricane Katrina, which cost insurers $41 billion, oil workers, utility crews, fishermen and other business owners fanned out across the Gulf Coast Tuesday to assess the damage. Retailers began restocking their shelves in anticipation of the region’s cleanup effort.

“We will be addressing our hardest-hit policyholders first,” said Elizabeth Stelzer, spokeswoman for Nationwide Mutual Insurance Co. “Those homes with a tree through a wall, an exposed roof, or other claims in which the home has become uninhabitable are the priority.”

Power outages from Hurricane Gustav continued to grow Tuesday with utility giant Entergy Corp. now saying it has the second largest number of outages in the company’s 95-year history, trailing only the devastation wrought by Katrina three years ago.

Losses on land were expected to total between $3 billion to $7 billion and oil-drilling damage at about $1 billion to $3 billion, Newark, Calif.-based Risk Management Solutions Inc. estimated. Catastrophe risk-modeling firm AIR Worldwide Corp., based in Boston, placed preliminary losses on land ranging between $2 billion and $4.5 billion.

“It’s still really early and we’re definitely evaluating the damage that happened,” said Matt Bordonaro, spokesman for The Travelers Group. “We are seeing more of a wind event, than a flood event.”

Insurance industry analysts warned that computerized data on insurance losses may understate actual costs because the figure don’t include damage to uninsured property or destruction caused by actions excluded from some policies, such as flooding. Total losses won’t be known for months.

Katrina, which struck three years ago last month, was the single largest natural disaster loss in the history of the insurance industry. Insurers paid $41 billion arising from 1.7 million claims for damage to homes, businesses and vehicles to policy holders in six states. Hurricane Andrew — the previous record holder — produced $15.5 billion in losses in 1992 and 790,000 claims.

Preliminary indications were that Gustav caused little damage to onshore and offshore oil facilities, though the full impact of wind and wave damage to platforms and pipelines likely won’t be known for a couple of days.

The Gulf Coast is home to nearly half the nation’s refining capacity, while offshore, the Gulf accounts for about 25 percent of domestic oil production and 15 percent of natural gas output.

Still, the price of oil tumbled nearly $7 a barrel in electronic trading on the New York Mercantile Exchange, suggesting traders were confident that the energy complex suffered only a glancing blow.

More than 1 million customers were without power across the region. Entergy alone said it has 825,000 customers without power, topping the number of outages after Hurricane Rita in 2005. Almost all the outages were in Louisiana, where Entergy has 1.2 million customers.

“Our transmission system has had massive damage,” Entergy spokesman Mike Burns said with damage to 191 transmission lines and 210 substations.

Eastbound traffic on Interstate 10 toward Louisiana picked up considerably as people started to make their way home, and retailers began to reopen stores closed as Gustav led to evacuations throughout the region.

Lowe’s Cos. Inc. said dozens of trucks full of supplies that had been stationed in the region were moving along highways Tuesday morning, bringing extra supplies of tarps, roofing supplies cleanup products and other material to the region as the massive cleanup begins.