Consolidated Health Informatics Initiative
Final Recommendation Sheet Format[1]

Domain Title and Team Lead:

Chemicals: Steven J Steindel, Ph.D (CDC)


To provide codes for chemicals of importance to health care outside of medications, which were covered in the CHI Medication standard. The workgroups feels that for health care purposes these chemicals will be those found in the workplace or the environment that might be related to health. Commonly the first, and perhaps only use, of a chemical code would be during a first encounter and perhaps be part of a History and Physical.

Domain/Sub-domain In-Scope (Y/N)
Non-medicine chemicals Y
Medication ingredients N

Alternatives Identified:

  1. SNOMED CT: Was not specifically reviewed by the Workgroup. SNOMED CT was reviewed as a means of identifying ingredients as part of the Medication Workgroup and found inadequate. A brief look at the Chemicals area by the Workgroup Chair indicated it was also not adequate for this domain.
  2. CDC NIOSH Registry of Toxic Effects of Chemical Substances (RTECS®): A database of 152,970 toxic chemicals (January 2001). The database is now privately maintained and available at a modest (starting at approximately $275 for a CD) subscription price. While this database appeared complete and was well targeted for toxicological information of medical importance, the subscription price and availability of a federally maintained system eliminated it from consideration. (See mapping below).
  3. Chemical Abstract Service (CAS) Numbers: CAS Numbers were investigated as they are the primary identification number assigned in the US. Approximately 22 million chemicals are registered with CAS. Licensing restrictions were viewed as preventing us of CAS Numbers for medical messaging. Note that CAS Numbers may be used freely for regulatory purposes and appear in many chemical databases for that reason.
  4. Environmental Protection Agency (EPA) Substance Registry System (SRS): See below for description.

Final Recommendation:

Literally thousands of directories of chemicals exist for many purposes. A review of the content and requirements of the EPA SRS indicated that it meet the needs of a CHI Validation study The EPA SRS as chosen because it is reasonably complete, readily available, in current wide-spread use and already has a structure that allows linkage to other data sources. As a federal government resource, there is no cost associated with access or use.

Content Coverage:

Data as of 11/10/03:

Number of substances currently in the SRS: 87707
Number of submitting organizations represented in the SRS: 37
Number of information resources included in the SRS: 965

The SRS contains substance identification information and listings of substances in EPA regulations and Agency programs. Substances are identified by common identifiers such as CAS Number and name (systematic or scientific). Each substance is linked to regulations in which it is referenced and program systems where it has been reported. Searches can also be done by specific regulation or program system.

The Standard in the present new format and in previous formats has been widely used, maintained and available from the EPA for a number of years. The Standard has information for STOrage RETrieval for Water Quality Data (STORET), Air Quality System (AQS), National Emission Inventory (NEI), and EPA Registry Names, substance lists for Green Chemistry Expert System (GCES), Chemical on Reporting Rules (CORR), Emergency Response Notification System (ERNS), Federal Insecticide, Fungicide, and Rodenticide Act Inert Ingredients in Pesticide Products (FIFRA-Inerts), Integrated Taxonomic Information System (ITIS), Safe Drinking Water Information System-Enviro (SDWIS-Enviro), OPP Registration Eligibility Decisions (OPP-REDS), Permit Compliance System-Enviro (PCS-Enviro), and Pesticide Product Information System (PPIS). Previous EPA registries, the Chemical Registry System (CRS) and the Biology Registry System (BioRS) have been retired with full function included in this standard.


The standard is owned and maintained by Environmental Protection Agency. It is part of the EPA System of Registries ( The System of Registries (SoR) provides a gateway and search capability to several registries and repositories residing in the Environmental Protection Agency’s (EPA) Office of Environmental Information (OEI). These registries comprise a critical link in EPA’s information architecture and are a vital component to the National Environmental Information Exchange Network (Network). Specifically, the SoR was developed to support the Agency’s data standards program and numerous Agency information technology initiatives, including the Agency architecture and data exchange with stakeholders through network nodes.

The registries provide identification information for objects of interest to EPA, Network trading partners, including states and tribal entities, and the public. These objects consist of data elements, XML tags, data standards, substances (chemicals, biological organisms, and physical properties), terms, facilities, regulations, and data sets that the Agency uses in its core business processes.

The Substance Registry System (SRS) is the Environmental Protection Agency’s (EPA) central system for information about regulated and monitored substances. The system provides a common basis for identification of chemicals, biological organisms, and other substances listed in EPA regulations and data systems, as well as substances of interest from other sources, such as publications. The SRS supports and conforms to EPA Chemical Identification Data Standard ( the EPA’s Biological Identification Data Standard (

Included is a download feature that lets you receive information about the contents the registry. There is a download section included at the bottom of each detail page. File formats include text report, Oracle (SQL* Loader), and comma-separated text files (for use in MS Access, MS Excel). Download files are available in a nonstandard, compressed file format that requires decompression software, such as WinZip or PKZip. Download of the complete database does not appear to be available at this time.

The registry data can also be accessed using the Environmental Metadata Gateway (EMG,, a search engine that enables users to search the metadata registry content using a Universal Resource Locators (URL) with integrated search capabilities. It enables users to search and seamlessly navigate to the detail pages meeting the search criteria. An EMG Search has been developed that enables system developers to build URLs to automatically query various substance data and display the appropriate detail information from EPA’s application, the Substance Registry System (SRS).

No license is required.


US Environmental Protection Agency (EPA) Substance Registry System (SRS) (www/

  • Establishing interagency communication so that medical needs are addressed in a timely and coordinated fashion. (It is the Workgroup’s understanding that this communication has started.)
  • Developing a mechanism so that similar tables from other agencies can be matched against the SRS table and missing elements added. (Note: this will require new, unidentified resources.)
  • Investigate availability of a subset or view of information from the database in an acceptable format for healthcare use as a no or low-cost distribution item. (EPA is willing to provide this view as a periodically updated, perhaps every six-months, compressed file for Internet download.)
  • Requirement for registering an Object Identifier (OID) if it is to be used in HL7 messaging.

[1] Information Sheet designed specifically to facilitate communication between CHI and NCVHS Subcommittee on Standards and Security resulting from May 20, 2003 testimony.  CHI may seek assistance to help further define scope, alternatives to be considered and/or issues to be included in evaluation process.