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MEMORANDUM | December 2, 2009 

TO Terri Johnson, EPA 

FROM Neal Etre, IEc 

SUBJECT NPL Site QC Effort 

NPL SITE QC EFFORT 

At the request of the Environmental Protection Agency’s Office of Superfund 

Remediation and Technology Innovation, Industrial Economics, Inc. (IEc) conducted a 

quality control (QC) effort to verify National Priorities List (NPL) site characterization 

information previously entered into the Comprehensive Environmental Response, 

Compensation, and Liability Information System (CERCLIS). Specifically, EPA 

requested that IEc: 

• Confirm the Site Category and Site Subcategory field entries (in general, these 

entries identify the industry sector associated with the NPL site) by crosschecking 

site information. 

• Suggest a correction for the Site Category and Site Subcategory fields based on 

our investigation.1

• Locate, if possible, the last date of known release associated with each NPL site. 

If this date was not readily available, IEc identified the last date of known 

operation or the closing date for the facility. 

• Match the confirmed/suggested Subcategory field with eight specific 3-digit 

NAICS provided by EPA. We also identified facilities that conducted recycling 

operations. 

Below, we provide a bulleted list that describes the data provided by EPA, along with the 

methods and caveats. 

CERCLIS DATA 

• The preliminary analysis was conducted on all proposed, final and deleted nonFederal Superfund sites as of August 5, 2009. In October 2009, IEc updated the 

database (and the analysis) to include recently listed, proposed, and deleted nonFederal superfund sites. Overall, we reviewed 1,633 records, which represent 

1,495 proposed, finalized, and deleted non-federal NPL sites. Note that sites may 

have multiple site type/NAICS designations in CERCLIS. 

 

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 In practice, the Category field does not provide useful information and was often blank in the CERLCIS data pull. As a 

result, and based on discussions with EPA, IEc spent relatively little effort to try to identify corrections for the Category 

field. 
• EPA also provided several spreadsheets that were produced by a similar QC effort 

conducted by EPA and IEc in April 2009. Where possible, we cross-referenced 

these spreadsheets with the CERCLIS data pull to obtain the most updated 

subcategory field as possible. 

METHODS 

For each site (which may have contained multiple records) in the CERCLIS data, 

IEc attempted to confirm the Subcategory field using the information available on 

the Internet from NPL site facts sheets and related site documents (e.g., Records of 

Decision (RODs) and Remedial Investigation/Feasibility Studies (RI/FSs).2

• For sites in which we determined that the Site Subcategory field contained an 

error, we suggested corrections. 

• For sites with multiple Subcategories entries, we examined each entry separately 

and made suggestions accordingly. 

• In addition, using the same sources, IEc attempted to identify the last date of 

known release for each site. If we were unable to locate this date, we identified 

the date that the site ceased operations. This data search was conducted for all 

sites in the data pull, including those previously QC’d in April 2009. 

• Given the quick turnaround nature of this effort and the large number of sites, IEc 

limited the search for information for a particularly site to a maximum of 15 

minutes. However, for some sites, we were able to confirm/find the information at 

faster rate. 

• Using best professional judgment, a best match was found between the CERCLIS 

site data and the definitions for the eight NAICS codes provided by EPA, 

including: 

o 325 Chemicals 

o 331 Primary Metals 

o 562 Waste Management 

o 324 Petroleum 

o 332 Fabricated metals (electroplating) 

o 321 Wood Products 

o 334 Computers/Electronics 

o 812 Personal and Laundry Services (Drycleaning) 

• In addition, EPA requested that we identify “recycling” facilities. However, 

recycling facilities do not have a designated NAICS code and can span a wide 

range of recycling operations. Recycling facilities were identified with a “REC” 

code in the database. Many of these sites were waste oil or oil recovery facilities. 

 

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 For those sites previously QC’d in April 2009, we did not QC the Site Subcategory, as this would have duplicated our 

previous effort. 
• For sites that did not match to these NAICS codes, we identified the 

confirmed/suggested Subcategory field. 

• A final MS Access database containing the original CERCLIS data and updates, 

along with data queries that provide IEc’s matches to the NAICS codes and 

Subcategories, was submitted to EPA on October 7, 2009. 

CAVEATS TO THIS EFFORT 

• The timeframe in which EPA requested this analysis to be completed required IEc 

to make quick decisions to confirm or reject the Subcategory field entries for each 

site. While all due care was given to examine each entry, IEc had to make 

professional judgments regarding the accuracy of the Subcategory fields. 

• The last date of known release was often difficult to identify within the time 

constraints. The documents examined rarely specified this date with absolute 

certainty. At times, IEc had to infer the last date of known release from site 

descriptions and other information. Given the uncertainty with some of the dates, 

EPA should use this information cautiously. 

• Where it was not possible to identify the last date of known release, IEc attempted 

to identify the date when the facility ceased the operations that resulted in the NPL 

listing. In general, this date was more readily available within the time 

constraints; therefore, we are more certain of the ceased operations date than the 

last date of known release.