Health and environmental agencies are advising people to avoid contact with the sludge. They recommend that people wear gloves, goggles, and dust masks, and that they wash promptly if exposure occurs.

　　EPA officials are directing people to its Web site (www.epa.gov) to inform themselves of the contamination risks.

　　But most people returning to the area don't have computers to get that information, said Erik Olson, an attorney for the Natural Resources Defense Council, an environmental advocacy group.

　　"If you [do] read the Web site," he added, "you practically have to have a degree in chemistry to understand it."

　　To better inform people of health risks, the Southern Mutual Help Association and Oxfam America are developing a program to give every returning resident a protective kit.

　　Each kit would contain waterproof suits, goggles(风镜), shoe covers, and masks, along with information about potential hazards, Volunteers would give out the kits at the security checkpoints that now stand at the major entrances to affected cities.

　　The groups have made a hundred demonstration kits, which cost about $100 (U.S.) each to produce, and have shown them to state leaders in Louisiana.

　　"The governor is really in favor of this," Subra said. "We just have to determine how we're going to fund them."

　　Toxic Mold Blooms

　　In addition to the toxic sediment, sprawling blooms of mold have now taken hold in many flooded homes. "The mold is growing everywhere-homes are just coated with it," Subra said.

　　The problem has become so widespread that federal health officials warned Wednesday of allergic reactions and toxic responses to the mold. Professionals should be hired to clean mold that covers more than ten square feet (one square meter), they urged.

　　"Those [surfaces] that can't be cleaned need to be removed," said Steven Redd, chief of the Air Pollution and Respiratory Health Branch of the U.S. Centers for Disease Control and Prevention (CDC).

　　The effects of the mold are already surfacing in Mississippi, where respiratory(呼吸的) problems are among the illnesses doctors there are reporting.

　　"We're seeing a lot of asthma from inhaling the mold," said Richard Paat, team leader of a temporary East Biloxi clinic. "And mouth sores from the bad water."

　　Due to contact with unclean water, 33 people in the flood zone have contracted Vibrio infections, according to the CDC. The infections are caused by a family of bacteria that live in contaminated salt water. They can cause serious illness, especially in people with compromised immune systems.

　　To date, six people have died from Vibrio infections.

　　"People had open wound and walked through floodwater with sewage in it," CDC spokesperson Von Roebuck said. "And these folks were having these wounds infected with Vibrio."

　　Disaster Response Care

　　"This is a highly contaminated area," said Susan Briggs, the physician overseeing FEMA's disaster-response medical teams in Louisiana and Alabama.