EPA RSL November 2024 Update - What Changed and Key Values

Overview

The EPA Regional Screening Levels (RSLs) were updated in November 2024, incorporating revised toxicity values, updated exposure parameters, and new risk calculations for approximately 890 chemicals across all environmental media. This page summarizes what changed in the November 2024 update and highlights the key values environmental consultants need to know.

For a general explanation of what RSLs are, how they are calculated, and how to use them, see our EPA RSL explained guide. This page focuses specifically on the November 2024 update.

What Are RSLs

RSLs are risk-based screening concentrations for soil, air, and tapwater that EPA uses to identify sites requiring further investigation under CERCLA. They are not cleanup standards - they are screening values. A concentration above an RSL indicates that further evaluation is warranted, not that remediation is automatically required.

RSLs are calculated using standardized exposure assumptions, toxicity values, and risk targets. The November 2024 RSL tables use:

Target cancer risk: 1 x 10-6 (one in one million)
Target hazard quotient: 1.0
Exposure scenarios: Residential and commercial/industrial

November 2024 Update Summary

The November 2024 update (the most recent RSL table as of this writing) reflects changes to toxicity values from EPA’s Integrated Risk Information System (IRIS), Provisional Peer-Reviewed Toxicity Values (PPRTVs), and other sources. RSLs are typically updated approximately twice per year as new toxicity data becomes available.

The full RSL summary table contains approximately 890 chemicals with screening values for residential soil, industrial soil, residential air, industrial air, and tapwater.

Key Value Changes to Watch

Lead in Soil

The residential soil lead RSL was reduced from 400 ppm to 200 ppm in January 2024, reflecting EPA’s updated lead risk modeling. This is one of the most significant RSL changes in recent years because lead is among the most commonly encountered contaminants at brownfield and industrial sites.

In October 2025, EPA issued a directive establishing a Removal Management Level (RML) for lead in residential soil at 600 ppm. The RML represents the concentration above which EPA removal actions may be warranted, while the 200 ppm RSL remains the screening level for further investigation.

This creates a practical framework:

Below 200 ppm: No further action typically needed based on screening
200-600 ppm: Further evaluation warranted but not necessarily requiring removal action
Above 600 ppm: Removal action may be appropriate under the RML

Benzene (Tapwater)

The residential tapwater RSL for benzene is 0.46 ug/L (at TR=1E-06, THQ=1.0). This is significantly lower than the drinking water MCL of 5 ug/L. When screening groundwater at CERCLA sites, the RSL - not the MCL - is the appropriate comparison value. The MCL applies as an enforceable standard for public water systems under the Safe Drinking Water Act, while the RSL is a risk-based screening value for site investigations.

PFAS Compounds

The November 2024 RSL table includes screening levels for several PFAS compounds. These values should be used in conjunction with the federal PFAS MCLs (4 ppt for PFOA and PFOS) and applicable state standards when evaluating PFAS at investigation sites.

Dust-Lead Action Levels

While not part of the RSL tables themselves, EPA finalized updated dust-lead action levels in January 2026: 5 ug/sq ft for floors, 40 ug/sq ft for window sills, and 100 ug/sq ft for window troughs. These values are used for lead hazard evaluations under 40 CFR Part 745.

How to Use the RSL Tables

Which Table to Use

The RSL calculator and generic tables provide values at multiple risk levels. For most screening purposes:

TR=1E-06, THQ=1.0 is the standard screening target used by most EPA regions and state programs. This is the version most consultants should use by default.
Some state programs or specific site conditions may warrant different risk targets. Always confirm with the applicable regulatory program.

Residential vs. Industrial

RSL tables provide both residential and commercial/industrial values. Use the scenario that matches the current or reasonably anticipated future land use of the site. Residential values are more conservative (lower) because they assume longer exposure durations and more sensitive receptors (children).

RSLs vs. State Standards

RSLs are federal screening values. They do not override state-specific cleanup standards. In Ohio:

VAP sites use CIDARS generic numerical standards, which are derived independently from RSLs
BUSTR sites use BUSTR action levels from the TGM, which are also independently derived
DERR-directed sites may use RSLs as screening values, with final cleanup levels established in the Director’s Final Findings and Orders

When comparing site data to both RSLs and state standards, the applicable standard depends on the regulatory program governing the site. RSLs are most useful as a screening tool when no specific regulatory program applies - for example, during Phase II ESAs conducted for due diligence purposes.

When the RSL Calculator Goes Offline

EPA’s online RSL calculator and VISL calculator have experienced periodic outages (most recently in February 2026). When the calculators are unavailable, use the most recently published RSL summary tables (available as downloadable Excel files from the EPA RSL website) for screening purposes. The summary tables contain the pre-calculated screening values for all chemicals at the standard risk targets.

The RSL Summary Table

The November 2024 RSL summary table (TR=1E-06, THQ=1.0) contains screening values for approximately 890 chemicals. The table includes:

Chemical name and CAS number
Residential and industrial soil screening levels (mg/kg)
Residential and industrial air screening levels (ug/m3)
Tapwater screening levels (ug/L)
Key toxicity values used in the calculation
Mutagenic and age-dependent adjustment factors where applicable

The complete table is available for download from the EPA RSL website. We maintain a copy of the November 2024 summary table in our data files for reference.

What to Do When RSLs Change

RSL updates can affect ongoing site investigations and existing risk assessments. When a new RSL table is published:

Active investigations: Compare current site data to the updated RSLs. If a previously screened-out chemical now exceeds its updated RSL, it may need further evaluation.
Completed risk assessments: Generally, completed risk assessments are not retroactively invalidated by RSL updates. However, if the site is still in active remediation or monitoring, the updated values should be considered.
State program sites: RSL changes do not automatically change state cleanup standards. VAP CIDARS values and BUSTR action levels update on their own schedules independent of RSL updates.

Source

EPA Regional Screening Levels (RSLs) - Generic Tables, November 2024, TR=1E-06, THQ=1.0. EPA RSL User’s Guide. EPA Lead RSL Update (January 2024). EPA Removal Management Levels for Lead in Residential Soil (October 2025 Directive).