Building Materials Make Wildfire Aftermath Worse

 Resiliency cannot include toxic chemicals

On January 7th 2025 fires tore through the town of Altadena and the Pacific Palisades leaving nothing but ash and charred building debris in its wake. My home was one of its casualties. Displaced and scrambling to find a place to go two questions instantly came to mind: 1.) How far do we need to travel from the burn zone to escape the toxic chemicals in the air? 2.) How long do we need to stay away?

WUI (Wildland-Urban Interface) Fires are different from fires that occur solely in nature, this is because the built environment is comprised of materials filled with chemicals that make the aftermath much worse. From halogenated flame retardants in our insulation and seat cushions to our coatings filled with carcinogenic VOCs like styrene and benzene to the forever chemicals like PFAS in our adhesives, sealants, and a whole host of other materials, the structures that once housed us are ironically making it harder to find a safe haven. Add heavy metals such as lead, arsenic, and hexavalent chromium to the mix and we have a toxic soup that is very difficult to clean up.

There is a lot of conflicting information on how far/long to stay away. While WUI fires are getting more devastating and prevalent, there hasn’t been a lot of research to give a definitive answer. In fact, the EPA only monitors a handful of chemicals. Just days after the Eaton Canyon Fire, the Air Quality Index indicated that the air quality posed little risk, when in fact chlorine levels in the atmosphere were 40 times the normal amount and lead was 100 times the usual level. No doubt a lot of the pollutants including ultra fine particulate matter come from burnt vegetation, however the long term concerns are rooted in the materials we create.

Effective resilient building strategies need to be designed and implemented ASAP. However, in order for these strategies to truly make a difference they need to be sustainable. We cannot simply focus on constructing buildings to sustain natural disasters. It is naïve to think we can always outwit nature’s wrath. Instead we need to factor in material composition and chemical safety or else we will eventually have very few places we can safely return to. It is understandable to want to come up with a quick fix to put people's minds at ease. But we can't rely on illusions of safety. What happens when another fire comes and renders the site unlivable? The jury is still out as to whether Altadena’s soil can safely grow food, or if I will ever really feel comfortable having my daughter play in the dirt. A part from removing the first 6 inches of top soil, the government isn’t doing any testing or providing any guidance on remediation. According to them, removing 6 inches of top soil is enough (another illusion of safety). Therefore it is up to the community at large to seek out proper resources (an important part of what it means to be resilient – community knowledge).

We at Ecomedes will be investigating the crossover between materials made to withstand extreme weather and materials that take chemical safety into consideration. We’d love to hear about any materials you know about. We are continuously inspired by our community and we’d love to learn from you.