RSEI Data Dictionary: Maximum Contaminant Level (MCL) Data

The following tables provide descriptions for each field in each table. Note that for the Geographic Microdata, "Other Geographies" includes block groups, census tracts, and ZIP code files. For more information, see the RSEI methodology document and the RSEI Microdata documentation.

Tables in the RSEI Data Dictionary
Facility	Chemical	Disaggregated Grid Cell Geographic Microdata	Aggregated Grid Cell Geographic Microdata for States
Off-site	MCL	Aggregated Grid Cell Geographic Microdata	Water Geographic Microdata
Submissions	Releases	Disaggregated Geographic Microdata for Other Geographies	Grid Shapefiles
Elements	Media	Aggregated Geographic Microdata for Other Geographies	Census Crosswalks
NAICS	Category	Geographic Microdata Shapefiles for Other Geographies	Population Data

Maximum Contaminant Levels (MCLs) are used to cap maximum modeled concentrations in drinking water systems. More information on MCLs.

These tables are from RSEI Version 2.3.12 (RY 2022) and cannot be used with tables from any other version.

RSEI MCL Table (Spreadsheet) (xlsx)

RSEI MCL Table (Text Format) (csv)

MCL Data
*Variable*	*Description*
CASNumber	Chemical Abstracts Service Registry Number, which identifies a unique chemical. For chemical categories, CAS Numbers begin with “N”, followed by three digits.
CASStandard	The Chemical Abstracts Service Registry Number identifies a unique chemical. The standard format contains three sets of numbers divided by hyphens (00-00-0).
ChemicalNumber	Unique internal identifier (links to Chemical table).
Chemical	Chemical name as listed in the Toxics Release Inventory.
MCL1988...MCL2021	MCL for each year an MCL was in effect.

RSEI Data Dictionary: Maximum Contaminant Level (MCL) Data

MCL Data

Risk-Screening Environmental Indicators (RSEI) Model