As New Orleans recovers from the devastation brought by Hurricane Katrina (search), more and more of its residents are returning to their old neighborhoods to find them covered in a filthy, black sludge.

Some of these residents have begun to report physical symptoms they believe are attributed to working around the murky mess.

The EPA (search) has said that the environment is safe, but the sight of the sludge and the emergence of what some are calling the "Katrina Cough" have some residents doubting validity of the agency's reports.

Click on the video box above to see a report by FOX News' Anita Vogel.

The EPA began testing the more than 7,000 miles of southeastern Louisiana affected by the hurricane after the floodwaters receded and has reported the levels of chemicals like lead and mercury to be acceptable by federal and state standards.

Still, many in Louisiana are skeptical of the EPA's findings — so much so that several organizations have been handing out free supplies like bleach, sponges and masks to those in affected areas. One environmental organization says that $20,000 of tests showed the chemical content in the sludge in St. Bernard's Parrish (search) was too high and too dangerous.

But the EPA says that $20,000 is not enough money to adequately assess contamination levels of an area so large, insisting that they are confident in their own results. The agency has yet to release long-term test results of the affected area.