NEW ORLEANS – A task force is calling on the American Society of Civil Engineers to come up with an ethics policy after critics raised questions about the group’s probes of the World Trade Center collapse and the failure of New Orleans levees during Hurricane Katrina.

Critics say the probes, commissioned and funded by federal agencies, were more about covering up human and agency misdeeds than determining what went wrong with the failed structures.

Last month, the society’s Task Force on Engineering Reviews said Reston, Va.-based ASCE should draw up an ethics policy to eliminate questions of possible conflicts of interest.

The panel started work after Raymond Seed, a levee expert with the University of California-Berkeley, sent a 42-page letter to ASCE in October 2007 accusing it of colluding with the Army Corps of Engineers to cover up engineering flaws found after Katrina struck in August 2005. Seed was on an independent levee investigation team funded by the National Science Foundation.

Seed’s team said corps and ASCE reports placed too much blame on the power of Katrina and did not spend enough time studying design flaws. The independent team also complained that the Army Corps and ASCE team obstructed access to data and tried to keep them away from the site of one of the major levee failures.

The letter also revived accusations that ASCE’s examination of the World Trade Center collapse was flawed. Critics have charged the group wrongly concluded the skyscrapers could not have been designed to withstand aircraft strikes.

In both cases, the society’s findings were called into question in large part because ASCE got money from government agencies. The society received a $1.1 million grant from the Army Corps to study levee failures and the Federal Emergency Management Agency paid the group about $257,000 to investigate the World Trade Center collapse.

An ASCE committee on professional conduct is looking into specific allegations of wrongdoing.