This essay is part of a series on environmental health.

Southern California was made to burn. The earliest wildfire recorded there was in 1889 and scorched 300,000 acres.

Given such a history, it might be tempting to see the calamitous Eaton and Pacific Palisades fires in Los Angeles County in January as part of a continuum. That would be a mistake. Rather, these fires show we need a new way of thinking about fire: as not only natural disaster, but also environmental threat with a high risk of long-term harms to health.

In part, this has to do with more frequent fires in the wildlife urban interface, where the city meets the wilderness. Both the Eaton and Palisades fires affected this type of terrain, which the historian and social critic Carey McWilliams (among others) once characterized as “rurban,” which is to say, untamed and densely populated at once.

Blazes in these areas consume, in addition to brush and undergrowth, all sorts of manufactured materials: lead paint and piping, lithium batteries and computers, cleaning solutions and artificial fibers, automobiles and electric wires. Soil samples collected from the Palisades and Altadena have revealed the presence of heavy metals and other toxic elements, including arsenic, lead and mercury. If not properly remediated, such contamination can linger, with potential effects including not only cancer but also damage to the brain and nervous system, especially in children under 3. That makes every fire in the wildlife urban interface a potential public health emergency.

Normally, the U.S. Army Corps of Engineers would take the lead on testing the soil and other sites for contamination after such an event. In February, however, the Corps announced it would not order sampling to see if properties had been properly decontaminated, citing the Federal Emergency Management Agency’s refusal to authorize remediation efforts of that scope. Such a pullback is hardly exclusive to Southern California; in recent months, FEMA has denied disaster aid to West Virginia and Washington. This means that survivors in Los Angeles, as well as elsewhere, are on their own more than ever.

Some residents of Altadena and the Palisades have paid for their own remediation, then waited, in some cases for months, to be reimbursed by insurance companies. Many homes that escaped fire damage were inundated with debris, some of it toxic. The administration has said it wants states and municipalities to take a larger role in mitigation and recovery, but the truth is they are already strapped. California is no exception.