“DANGER: Lead Work Area” reads a sign on a front door of an Altadena home. “May damage fertility or the unborn child. Causes damage to the central nervous system.”

Block after block there are reminders that contaminants still linger.

House cleaners, hazardous waste workers and homeowners alike come and go wearing masks, respirators, gloves and hazmat suits as they wipe, vacuum and power-wash homes that weren’t burnt to ash.

It’s been a year of heartbreak and worry since the most destructive wildfires in the Los Angeles area’s history scorched neighborhoods and displaced tens of thousands of people. Two wind-whipped blazes that ignited on Jan. 7, 2025, killed at least 31 people and destroyed nearly 17,000 structures, including homes, schools, businesses and places of worship. Rebuilding will take years.

As the Los Angeles wildfires died out in January, firefighters trekked through the burn zones to take stock of the destruction. For every home they found leveled, they counted another still standing. The structures looked fine from the outside, but ash and oily soot often coated the floors and furniture, while invisible chemicals burrowed into clothes, blankets and even walls.