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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. The revisions were based on a comprehensive review and update of all the information contained in SCDM. 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 provided increased consistency across EPA programs. One new entry (PDF) (1 pg, 32K) was added in the January 2014 version of SCDM that was not in the 2004 version or in the interim reports published between 2004 and 2014; no entries were removed. Following the January 2014 publication, revisions were made to SCDM on an as-needed basis to reflect changes within the cited references. The current version of SCDM is the June 2014 publication. A Change Control and Errata Sheet (PDF) (3 pg, 98K) is provided to document and track any changes or corrections that have been made since the January 2014 publication; these changes are reflected in the reports below.


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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