SANTA ROSA, Calif. — Dr. Karen Relucio has heard reports of people digging into the ashes of their burned homes in recent days without gloves, wearing only shorts and T-shirts, looking for sentimental items that might have survived California’s horrific wildfires. And as the chief public health officer in Napa County, one of the hardest-hit places, she has used her office as a bully pulpit to urge them to stop, immediately.
“Just think of all the hazardous materials in your house,” she said in an interview. “Your chemicals, your pesticides, propane, gasoline, plastic and paint — it all burns down into the ash. It concentrates in the ash, and it’s toxic,” said Dr. Relucio, who declared a public emergency over the hazardous waste from the fires, as have at least two other counties.
California’s fires are far from out. They have killed at least 41 people and burned about 5,700 structures and over 213,000 acres since they exploded in force on Oct. 8 and 9 — record totals for a state that is used to wildfires. Thousands of firefighters are still at work fighting blazes and tens of thousands of people remain under mandatory evacuation from their homes, though fire officials have expressed cautious optimism about bringing the fires into containment.
But even as the smell of smoke still wafts through this area north of San Francisco, public health officials and environmental cleanup experts are starting to think about the next chapter of the disaster: the huge amount of debris and ash that will be left behind.
In whole neighborhoods here, a thick layer of ash paints the landscape a ghastly white. Wind can whip the ash into the air; rain, when it comes, could wash it into watersheds and streams or onto nearby properties that were not ravaged by fire.
And the process of cleaning it all up, which has not even begun, is very likely to bring its own thorny set of issues, in the costs, timetables and liability questions — all compounded by scale, in the thousands of properties that must be repaired and restored.
“In modern times this has got be an unprecedented event, and a major hazard for the public and for property owners,” said Dr. Alan Lockwood, a retired neurologist who has written widely about public health. He said an apt comparison might be the environmental cleanup after the terrorist attacks of Sept. 11, 2001, in New York, as debris and dust swirled through Lower Manhattan.
As could well happen too in California, Dr. Lockwood said, the health and environmental effects were felt long after the attack, in the chemicals or pollutants workers and responders at the site, and the public at large, may been exposed to as the cleanup went on.
Household building materials are obviously different from the components of a concrete tower. But they pose risks too. Treated wood in a house’s frame, for instance, put there to prevent bacteria growth, can contain copper, chromium and arsenic. Consumer electronics contain metals like lead, mercury and cadmium. Older homes might have asbestos shingles. Even galvanized nails are a concern because when they melt they release zinc. All are potentially harmful.
“It’s a completely complex mixed bag of different stuff that’s there,” said Geoffrey S. Plumlee, associate director for environmental health with the United States Geological Survey.
Dr. Plumlee led a study after several Southern California wildfires in 2007 that found that ash from burned-out residential areas contained elevated levels of arsenic, antimony and metals including lead, copper and chromium. In most cases the levels were above federal Environmental Protection Agency guidelines for soil remediation.
After a fire in Slave Lake, Alberta, in 2011 that destroyed about 400 homes, the city landfill was found to be leaching toxins after fire debris was deposited there.
In California, the road ahead to cleanup and the safe return to properties will probably not be smooth or fast, public health officials and cleanup experts said. The sheer number of communities affected and properties destroyed creates a greater challenge than any the state has faced in recent history.
Local and state agencies, focused on active fires, have not yet sorted out who will take the leadership roles. Even determining how severely lands are affected and the estimated costs of remediation lay ahead in the weeks and months to come.
At a packed public meeting in the basketball gym at Santa Rosa High School on Saturday, some residents said they worried that the cleanup could go on for years and asked state officials if they could proceed on their own.
The answer they got was a qualified yes. An approved contractor can be hired, if one is available. Otherwise the cleanup should be free in most cases, residents were told, paid for with taxpayer money or private insurance if a homeowner has a debris-removal clause in the insurance policy on the house.
But state and federal officials said on Monday that many of the details of how this cleanup would work remained unsettled. That is partly because the focus has been on response to the fires and the fatalities, and the 40,000 people still evacuated from their homes, but also because of the complex mix of properties affected on both public and private lands.
“There are more questions than answers,” said David Passey, a spokesman for the Federal Emergency Management Agency. He said, for example, that FEMA, the federal government’s lead disaster response agency, typically concentrated on public property, not private, unless individual counties declare the private properties a public health and safety risk. Counties and cities can also take the lead on cleanup, he said, and that too has not been fully sorted out.
Mark Oldfield, a spokesman for the California Department of Resources Recycling and Recovery, which administers state-managed waste handling and recycling programs, said a typical situation for cleanup would include a kind of triage, with the most hazardous materials as a site handled first, typically by the California Department of Toxic Substances Control. That agency would evaluate and remove hazardous debris, which can range from asbestos siding or pipe insulation to paints, batteries, flammable liquids and electronic waste like computers and monitors.
After that, contractors under CalRecycle’s auspices could focus on remaining debris removal for recycling (metals and concrete) or disposal (ash and contaminated soil), Mr. Oldfield said. Then the land could be prepared for potential rebuilding. But, he added, “With fires still active in many areas, there is not yet a timetable for cleanup efforts to begin.”
Dr. Relucio, Napa County’s public health director, said that in the meantime, people who go back to their properties should protect their eyes, lungs and skin, with long sleeves and pants, boots, glasses, and a good quality N95-rated mask available in most hardware stores.
Dr. Lockwood said a secondary caution for anyone entering a burned site is human idiosyncrasy, in the things people store in garages, use in their hobbies or just never got around to throwing away.
“One never knows what people have stashed in their homes,” he said.