After fires, scientists doubt lead-in-soil limit

Is the state standard too lax? What survivors should know.

- BY NOAH HAGGERTY

A BACKHOE scrapes 6 inches of dirt off land in Pacific Palisades. Simply adding fresh top soil can also offer protection, experts say.

It's a number thousands of Palisades and Eaton fire survivors have come to depend on: 80 milligrams of lead in each kilogram of soil.

Below this concentration, California has historically deemed yards safe enough for families to rebuild and move home after a fire. Any more, state scientists say, comes with a notable risk of kids developing neurological problems from the lead they accidentally inhale, absorb through their skin and eat while playing outside.

In a paper out Friday, Harvard environmental health researchers argue it's not strict enough. The scientists contend that the state's health standard is not based on sound science and should sit around 55 milligrams per kilogram of soil (a measure also referred to as "parts per million") instead.

"We're getting asked these questions every single day, like every other scientist ... 'Is it safe for my kids?' " said Joseph Allen, lead author on the paper and a Harvard T.H. Chan School of Public Health professor who has been working with fire survivors through the LA Fire HEALTH Study research program. "I can't look at somebody in the eye anymore, knowing what I know about these models, and tell them yes."

However, other soil and health researchers said it's a debate best confined to technical scientific papers, with few implications for fire survivors wondering whether their property is safe.

Here's what you should know:

Why a stricter standard?

Lead can cause negative health effects at virtually any level of exposure, so scientists at California's Department of Toxic Substances Control set their health standard for lead in residential soil by starting with a goal: The standard should prevent children from losing one IQ point due to lead exposure.