Lead in Soil: EPA Takes Important First Step to Tighten Limits

What Happened?

EPA announced on January 17 that it “lowered recommended screening levels and strengthened guidance for cleaning up lead-contaminated soil in areas where children live, learn, and play.” Since 1994, the screening levels had been 400 parts per million (ppm). Now, the level is 100 ppm where other localized sources of lead exposure are present such as lead-based paint, lead service lines (LSLs), or an area that does not meet lead air standards. For other areas, the level is 200 ppm.

In justifying the change, EPA estimated that at 200 ppm, five young children out of one hundred living, learning, and playing around the soil are expected to have blood lead levels of 5 micrograms/deciliter (µg/dL) or greater with a geometric mean of 2.3 µg/dL.1 At 100 ppm, the blood lead levels would drop to 3.5 µg/dL and 1.7 µg/dL respectively. For context, CDC uses 3.5 µg/dL to identify children with higher levels of lead in their blood compared to most children.2

The change is effective immediately, but the agency is taking comments until March 17.

Why It Matters

The guidance, when fully implemented, should have a significant impact on cleanups where there are industrial and commercial sources of lead contamination, past or present. Note that while EPA describes it as residential, the guidance applies to “vacant lots in residential areas, schools, day-care centers, community centers, playgrounds, parks and other recreational areas and green ways.”

EPA estimated that this change will reduce lead exposure over the next 60 years for more than 436,000 young children (younger than seven years of age) and 15.7 million adults aged 40 to 79.3 The total cost will exceed $20 billion with benefits ranging from $12 to $37 billion.

However, it does not change the lead-based paint hazard standards under the Toxic Substances Control Act (TSCA). Those outdated standards, set 23 years ago, apply to bare soil on residential real property or on the property of a child-occupied facility that contains 400 ppm or greater of lead in a play area or average of 1,200 ppm in the rest of the yard. In 2001, the Ninth Circuit Court of Appeals directed EPA to revise those standards, but the effort is considered a long-term action by the agency.

Our Take

We applaud EPA for taking this important step forward as part of a long-overdue update to how the agency evaluates lead contaminated soil. And it is good to see EPA accounting for other localized sources by tightening the screening level in those situations.

However, we are concerned that EPA did not use 3.5 µg/dL (CDC’s reference level) as the basis of the screening level.4 After all, a screening level is primarily a trigger for closer evaluation—not an enforceable standard.

Unfortunately, where no clear industrial or commercial source of contamination is identified, children are unlikely to benefit. In its American Healthy Homes Survey II, HUD estimated that homes built before 1940 had an average level of 405 ppm in bare soil. The average was 87 ppm in homes built between 1940–1959.

Sieved or Total?

In 2016, EPA recommended that soil and dust samples be sieved to screen out particles greater than 150 µm in size (No. 100 sieve) to better represent the type of particles that would adhere to skin and then be ingested. For context, this is similar to flour used for cooking. 

In contrast, TSCA’s lead hazard standard does not require sieving. 

For a comparison of how sieving impacts the measured lead levels in soil, see the results of sampling around lead telecom cables in Louisiana5

Next Steps

While the guidance is effective immediately, it will take time to impact existing sites as EPA and states periodically review existing decisions. However, there is an immediate opportunity to address ongoing sources of contamination such as lead telecom cables. Unleaded Kids will be tracking implementation of the guidance in this context. We will also continue to press for EPA to revise the TSCA lead-soil hazard standard as directed by the Ninth Circuit Court of Appeals.

  1. The estimates are based on version 2 of EPA’s IEUBK risk assessment model using the 95th percentile and the geometric mean. The estimates include a national default blood lead concentration from general sources such as lead contamination of food. ↩︎
  2. CDC refers to this level as the Blood Lead Reference Value. ↩︎
  3. Using the midpoint value from EPA’s Economic Assessment at Exhibit ES.7 ↩︎
  4. EPA used it for the 100 ppm but that only applies where there are other localized, non-soil sources of lead exposure. ↩︎
  5. See data at https://response.epa.gov/sites/16204/files/Lead%20Sampling%20Results.pdf. ↩︎

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