Residents worry about the toxic substances in debris from houses, which they are forbidden from collecting in plastic trash bags. Silt from the canals and Lake Pontchartrain contains toxic pollutants and covers the city. The canals carried the storm surge from Lake Pontchartrain into the city, causing the massive flooding. Degradation of marshland along the coast of Louisiana also contributed to the flooding. This elderly housing complex in the Tremé doesnt seem damaged, but must be gutted due to mold. The black mold grows in the drywall, which must be removed before the building can be inhabited again. Even on upper floors, which didnt flood, mold grew to the ceiling, filling the building with its stench. The class recommended that playgrounds be the first focus of environmental cleanup to protect returning children.