The floodwaters receded, but now flood victims are fighting a darker, fuzzier enemy.
Tracks of greenish-black mold are streaking across walls and spreading into the fabric of clothes and furniture of homes damaged by Tropical Storm Irene. That is the visible part.
The real trouble hides behind walls, under carpets and even in the air where spores float around looking for new places to propagate.
"Each single spore can start a colony," said Vishnu Chaturvedi, director of the mycology laboratory at the Wadsworth Center in Albany. The state-run lab is dedicated to testing and studying fungus.
Mold lives in the soil and air and is nature's recycler. It feeds off of dying plant material, breaking it down to basic elements like carbon and nitrogen, Chaturvedi said.
Normally, the dry environment inside a home prevents mold, but damp flood-damaged houses are breeding grounds. Indoors, mold feeds off organic materials in drywall, ceiling tiles, fabric, wood and paper. After a flood, mold can start growing within 24 to 48 hours.
"Right now, this is the week when people are starting to see the mold," said David Johnson, owner of Professional Fire Restoration Services in Albany.
If the problem is isolated to a couple of spots, homeowners can remove it on their own. But if it is widespread, Chaturvedi said call a professional.
The first priority is to get rid of the mold and dry out the area. As painful as it might be, the professionals say throwing out items that have mold growth is the best method. Toss out the furniture, suitcases and carpets. Running moldy clothes through the wash with bleach will kill the mold, but dead mold can still be irritating to people with allergies.
Equipment and tools made of metal can be bleached and saved. For objects of high value, remove the mold by freezing the object in the refrigerator and scraping or sanding off the frozen remains.
If there is mold growth on the walls, there's probably more behind it.
"That's going to be a mold factory," Johnson said.
The professionals recommend removing one to two feet of dry wall and insulation and discarding the material. Sometimes, homeowners are too timid about removing an adequate amount of wall, something that professionals are less shy about.
One square inch of mold can hold 1 million to 10 billion spores, warned Michael Phillips, general manager of the Colonie-based fire and flood restoration services of MacFawn Enterprises. So, it's best not to leave any moldy material behind.
Keep the walls open to allow the air to circulate, they said. Clean the areas with diluted bleach (one cup of bleach for each gallon of water). Bleach, however, does not fall into the category of "more is better" because undiluted bleach is ineffective, Phillips said. Chaturvedi, the scientist, explained water reacts with a chemical in bleach and forms hypochlorous acid, which is the disinfection agent.
Run a dehumidifier to pull moisture out of the air, but use fans cautiously, Phillips said. Fans speed the drying process, but can spread airborne spores to new areas of the house. Drying can take three to five days, or more.
Homeowners can remove mold from wood framing with sandpaper. Professionals may also use pressure treatments of dry ice or baking soda, microbicide sprays and sealants. Some hardware stores may carry microbicides and sealants.
The CDC recommends wearing an N95 face mask when cleaning large areas of mold, but a regular dust mask does not provide protection.
Mold generally does not harm humans, but it can be irritating to people with allergies and asthma. It can also aggravate problems for anyone a compromised immune systems, including people with cancer and HIV.
A professional cleanup costs $1,800 to $5,000 or more for badly damaged homes, but how do you know when to call someone?
"If you see 10 or 12 inches of mold around the perimeter (of a room), you are in over your head," Phillip said.