The storm dumped up to a foot of rain and lashed the border region of the two states with 120 mile per hour winds when it crashed ashore from the Gulf of Mexico on Saturday.
Rita pushed in a 15-foot storm surge that swamped the Cajun communities of southern Louisiana and left hundreds of people stranded in or on top of their submerged homes.
The storm dealt a glancing blow to Houston, center of the U.S. oil industry, but badly damaged small towns and cities to its east.
Shaken survivors emerged to find a panorama of destroyed buildings, debris-strewn streets, downed power lines and toppled trees. Those who defied evacuation orders and rode out the storm said it was a frightening experience.
"I called on Jesus for four hours," Gloria Matthews told the Beaumont Enterprise. "The house was shaking and the wind was roaring."
A key natural gas installation in southern Louisiana known as Henry Hub, through which a third of the nation's natural gas flows and where spot gas prices are determined, was damaged by Rita, Louisiana Gov. Kathleen Blanco said.
"We understand there is a gas leak and...a possible shearing of an oil storage tank," Blanco told CNN.
She gave no other details about the damage or its effects on gas delivery, but said the leak would have to be plugged.
"We're watching the situation very carefully," Blanco said.
Rita and Katrina knocked out nearly all energy production in the offshore oil fields of the Gulf of Mexico and 30 percent of the U.S. refining capacity onshore.
At least three oil refineries were damaged by Rita, oil companies said.
Rita cut power to more than 2 million people in Texas and Louisiana. Utility companies said it could take a month to fully restore electricity in the stricken region.
Risk modeling experts said up to $6 billion in damages had been inflicted by Rita, which