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Superfund Chemical Data Matrix (SCDM)

The Superfund Chemical Data Matrix (SCDM) is a source for factor values and screening concentration benchmarks that can be applied when evaluating potential National Priorities List (NPL) sites using the Hazard Ranking System (HRS). Factor values are part of the HRS mathematical equation for determining the relative threat posed by a hazardous waste site and reflect hazardous substance characteristics, such as toxicity and persistence in the environment, substance mobility and the potential for bioaccumulation. Screening concentration benchmarks are environment- or health-based substance concentration limits, including some developed by or used in other EPA regulatory programs. SCDM contains HRS factor values and screening concentration benchmarks for hazardous substances that are frequently found at sites evaluated using the HRS, as well as the physical, chemical and radiological data used to calculate those values. The accompanying SCDM Methodology report describes how data are selected or calculated for inclusion in SCDM.

On January 30, 2014, the EPA released an updated SCDM with many revisions to the HRS factor values and benchmarks. These revisions were necessary because of updates to some of the toxicity data, as well as updates to several of the equations used to determine screening concentration benchmarks. This update also provides increased consistency across EPA programs. The factor values and benchmarks provided in this January 2014 update supersede any previous values.


The Superfund Chemical Data Matrix (SCDM) contains factor values and benchmarks used for applying the Hazard Ranking System (HRS) [40 CFR Part 300 Appendix A, 55 FR 51583] to evaluate potential National Priorities List (NPL) sites. The physical, chemical, toxicological and radiological parameters used to calculate the factor values and benchmarks are obtained from references listed in the SCDM Methodology. The references and the data extracted from these references were selected to meet specific HRS requirements and conditions which may not be applicable or representative for other uses. In addition, the parameter values are updated only on an "as needed" basis. As a screening tool, the HRS and SCDM are used for quickly assessing sites at the screening stage and data used to perform this task may not be applicable for other site specific purposes.

The parameter values in SCDM should be used for HRS and NPL purposes only.

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Superfund Chemical Data Matrix Report

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