WASHINGTON -- A new report from the Democratic opposition research group American Bridge's Bridge Project describes the way Charles and David Koch, the influential conservative billionaires, put their vast resources into actions that exacerbated the impact of Hurricane Katrina and stalled the Gulf Coasts recovery.

The report, released Thursday, highlights the Koch brothers' influence on the region before and after the storm, including constructing and operating pipelines that destroyed wetlands south of New Orleans and attempting to obstruct legislation that would have aided the recovery.

The report describes a federal class-action lawsuit claiming that Koch Pipeline Company and other major oil companies were partly responsible for the destruction of 1 million acres of marshlands and also for millions more acres of dying marshland. The destruction of the marshlands eliminated New Orleans' "natural protection against hurricane winds and storm surges, according to the lawsuit. The case was later dismissed because a judge deemed it ambitious.