Responding to criticism by a congressional report, the state's top environmental official is denying that not enough was done to monitor the risk from asbestos in the cleanup from Hurricane Katrina.

On Thursday, Mike McDaniel, secretary of the Louisiana Department of Environmental Quality, called a Government Accountability Office report critical of asbestos monitoring "riddled with unsubstantiated editorial comments, misleading statements and inaccuracies."

He made those comments in a letter sent Thursday to the GAO, Congress' investigative arm.

Environmental officials in Louisiana are highly sensitive to criticism because they feel that environmental risks have been overblown in the wake of Katrina and hurt the recovery.

It was common for New Orleans to be described as a toxic zone after Katrina hit on Aug. 29, 2005, and flooded 80 percent of the city.

Since the dirty flood waters were pumped out, environmentalists and officials have clashed on a range of issues from the use of landfills to how well oil spills were cleaned up. State and federal agencies say the storm has created few long-term environmental hazards, a finding questioned by environmental groups.

The GAO issued its report late last month and it said environmental regulators potentially exposed scores of residents, volunteers and workers to asbestos fibers by not doing more to monitor the contaminant in the cleanup after Katrina.

The GAO report was aimed at the Environmental Protection Agency, but DEQ has been more aggressive than the EPA in defending the way the Katrina cleanup has been handled.

Contrary to GAO's findings, state officials Thursday said that there has been an exhaustive effort to monitor for asbestos. DEQ said that no measurable amounts of asbestos showed up in more than 20,000 samples, most of them taken during demolitions.

John B. Stephenson, the director of the GAO's natural resources and environment office, said that the GAO found no evidence of monitors during demolitions. Asbestos contamination was of particular concern because many of the buildings being torn down in New Orleans are old and would likely contain the cancer-causing fibers, he said.

DEQ said that besides monitoring demolition sites, crews have had to follow strict guidelines on how to handle buildings that might contain asbestos. They wet buildings down so the fibers do not get airborne and bag the debris on its way to the landfill, officials said.

The GAO report also said the environmental regulators at times issued "unclear and inconsistent" information on the potential danger of asbestos, mold and other contaminants as people went about gutting and demolishing homes.

Again, DEQ countered that regulators were quick to issue information on potential hazards and promptly made sampling data available.

(Copyright 2007 by The Associated Press. All Rights Reserved.)