On January 17, 2024, the United States Environmental Protection Agency (EPA) announced immediate lowering the residential soil screening level from 400 parts per million (ppm) to 100 ppm at properties with multiple sources of lead exposure. For “soil-only” exposures the new screening level is 200 ppm. The industrial soil screening level, currently set at 800 ppm (see EPA’s Regional Screening Levels [RSL]) is not addressed in the press release.    

The agency is taking this action as part of its prolonged efforts to protect communities from lead, recently outlined in the Federal Lead Action Plan. EPA has taken a particular interest in protecting children’s health from the effects lead exposure on cognitive development in early life stages. Moreover, children have greater potential for exposure to lead in urban soils, lead-based paint in old homes, and via residential lead piping still present in some parts of the country. Multiple exposure pathways for lead are frequently characteristic of disadvantaged communities, the latter being the focus of agency’s Environmental Justice program influencing multiple policies. The announcement of the new soil screening levels for lead is part of EPA’s multifront approach to address lead in homes, lead abatement, drinking water, ambient air, and waste. Other federal agencies such as the Federal Drug and Food Administration (FDA) take parallel measures to control lead in cosmetics, pharmaceuticals, consumer goods, and food.             

Notable Highlights and Changes in the Soil Lead Guidance

This month, EPA updated the residential soil screening levels for lead, including adding a new “sensitive receptor” category where exposures entail multiple sources. Industrial soil screening levels appear unchanged at this time.   

The new residential soil screening levels represent a significant departure from the decades-long 400 ppm/800 ppm pair serving as the basis for soil remediation at contaminated sites. Going forward, lead assessment and remediation will face additional challenges.

Implications of Soil Screening Level Developments on Regulatory Compliance and Environmental Liability

While the soil screening levels are not meant as enforceable cleanup standards, risk assessment and remediation practitioners frequently face regulatory decisions that adopt screening levels as de facto cleanup levels. This is particularly true for EPA’s lead screening levels, which seem to frequently end up as soil cleanup goals. Therefore, this development cannot be taken lightly, particularly at sites subject to Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA, aka Superfund) and/or Resource Conservation and Recovery (RCRA) compliance requirements. Under Superfund, the lowering of screening levels may subject certain sites to CERCLA reopeners, post-closure scrutiny, ballooning of remedial costs/liabilities, and re-emergent risks previously deemed acceptable. Moreover, a domino effect is likely in many state-led cleanup programs.        

What Happens Next

While the public comment period remains open through March 17, 2024 (EPA-HQ-OLEM-2023-0664), the fait accompli nature of EPA’s approach is unlikely to result in the return of the 400 ppm screening level. More likely, the upcoming (March 2024) RSL table revisions will irreversibly supersede previous screening levels. There is no clarity if/when EPA may lower the commercial/ industrial soil screening level of 800 ppm.    

Navigating the Impact of Lowered Screening Levels

With the new, significantly lowered screening levels for lead, it is now more important than ever to focus on the remedial strategy of establishing risk-based, site-specific cleanup levels (SSCLs). This process should be closely tied to conceptual site models (CSM), complete exposure pathway analysis, anthropogenic background studies, soil-to-groundwater leaching prediction, waste profiling, and the incorporation of available lines of evidence to differentiate amongst hypothetical and actual risks. This fit-for-purpose approach offers relief from the default, highly conservative screening level assumptions, which often result in excessive cleanup costs. SSCLs when used in conjunction with CSMs have proven to yield cost-effective cleanup strategies.

Need more details?

Trihydro’s environmental risk assessment and remediation specialists have worked on lead sites for decades. Even before EPA’s announcement, we have developed time-tried tools, skills, and techniques to address lead in soil at sub-400 ppm levels for multiuse sites. Reach out for more information on EPA’s announcement, or to be put in touch with one of our lead experts.