Water Pollution Search Results Help - TRI

The TRI Water Pollution Search Results page presents results that meet the search criteria specified on the Search page. Note that the search criteria you entered on the search page appears at the top of the page.

Note the following definitions anywhere they appear on the TRI Search Results page:

  • Direct Discharges: Wastewater released directly into U.S. surface waters
  • Indirect Discharges: Wastewater transferred to publicly owned water treatment works (POTWs) for further treatment prior to release into the environment. The reported TRI chemical release amount is adjusted to account for removals at the POTW.

Click on the links below to quickly find the table of interest.


Search Statistics - Facility Counts

This table provides information about the scope of the facilities included in your search results. Statistics include the total number of NPDES permits that are included in the search results, the number of permits that have monitoring data, and the number of permits that have discharge limits. Definitions for each count can be found in TRI Search Statistics Help.

Note that the facility counts and summary tables below do not include pollutants for which annual loadings cannot be calculated, such as temperature and pathogen indicators. Run a separate search for these pollutant categories.

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Top Chemicals by Toxic-Weighted Pounds (TWPE) (Year)

For a given year, this chart lists the top ten chemicals by name and their total pounds (lb/year) or toxic-weighted pound equivalents (TWPE) (lb-eq/year) reported to TRI as released directly and indirectly. The chemicals are listed in order of decreasing mass and TWPE.

EPA calculates TWPE  using pollutant loadings and chemical-specific toxic weighting factors (TWFs) in order to rank the relative toxicities of different pollutant discharges. TWPE is not a measure of risk or potential for human health impacts. For more information about TWPE, see ECHO Frequently Asked Questions.

For a complete list of chemicals click the "Download All Data" button.

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Top NAICS Discharges in Pounds/Toxic-Weighted Pounds (TWPE) (Year)

This table lists the NAICS codes with the ten largest discharges for a given year that meet your search criteria. The NAICS code discharges are ranked in order of decreasing chemical mass. For a complete list of all chemicals click the "Download All Data" button.

NAICS Code
The facility's primary North American Industry Classification System (NAICS) code and description. NAICS has replaced the U.S. Standard Industrial Classification (SIC) system. The system was developed to give special attention to developing production-oriented classifications for (a) new and emerging industries, (b) service industries in general, and (c) industries engaged in the production of advanced technologies.
NAICS industries are identified by a 6-digit code. The first two digits represent the Industry sector, in which there exist 20 broad sectors. The third digit represents industry subsector, the fourth digit represents industry group, the fifth digit represents industry, and the sixth digit is U.S., Canadian, or Mexican National specific. For more information, see the U.S. Census Website.
NAICS Description
Description that is linked to the NAICS Code that identifies the primary activity of the facility.
Top Chemical
The name used in ICIS-NPDES to identify the chemical discharged. Of the chemicals discharged by each NAICS code, the chemicals with the highest annual load is listed.
Direct/Indirect TRI Pounds
For the top chemical for each NAICS code, the annual mass (in units of pounds/year) for direct and indirect discharges. This table does not display chemicals that have a total annual load of zero.
Direct/Indirect TRI TWPE
For the top chemical for each NAICS code, the relative toxicities of different pollutant discharges (in units of pounds-equivalent per year) for direct and indirect TRI. This table does not display chemicals that have a total annual load of zero.
Top Pollutant TWPE
For the top chemical for each NAICS code, the relative toxicities of different chemical discharges (in units of pounds-equivalent per year). TWPE is calculated by multiplying the pollutant mass (in pounds) by its toxic weighting factor. This value is not a measure of risk or potential for human health impacts but is a relative measure of the potential toxicity between pollutant discharges. For more information about TWPE, see ECHO Frequently Asked Questions.
Not all chemicals have a toxic weighting factor (for example, Total Suspended Solids), which means that these pollutants do not have a toxicity score (i.e., TWPE = 0).

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Top Facility Discharges in Pounds/Toxic Weight Pounds (TWPE) (Year)

This table lists the facilities with the ten largest discharges that meet your search criteria. The facility loads are ranked in order of decreasing mass or decreasing toxic-weighted pound equivalents. Click on the facility name to bring up the facility information page. For a complete list of all chemicals click the "Download All Data" button. The "Browse All Facilities" button will provide a list of all facilities meeting the search criteria.

  • Region (first-level, 2-digit HUC)
  • Subregion (second-level, 4-digit HUC)
  • Accounting unit (third-level, 6-digit HUC)
  • Cataloguing unit (fourth-level, 8-digit HUC)
  • Watershed (fifth-level, 10-digit HUC)
  • Subwatershed (sixth-level, 12-digit HUC)
TRI Facility ID
A unique 15-character ID assigned for each facility within the Toxics Release Inventory (TRI) program. The format is ZZZZZNNNNNSSSSS, where ZZZZZ = ZIP code, NNNNN = the first 5 consonants of the name, and SSSSS = the first 5 non-blank non-special characters in the street address.
Facility Name
The primary name used to identify a facility in ICIS-NPDES.
City, State
The city name and two-character state abbreviation for the facility location. City names can be blank in FRS and ICIS-NPDES. The Water Pollution Search will display states for all facilities and the city name, if provided.
NAICS Code
The facility's primary North American Industry Classification System (NAICS) code and description. NAICS has replaced the U.S. Standard Industrial Classification (SIC) system. The system was developed to give special attention to developing production-oriented classifications for (a) new and emerging industries, (b) service industries in general, and (c) industries engaged in the production of advanced technologies.
NAICS industries are identified by a 6-digit code. The first two digits represent the Industry sector, in which there exist 20 broad sectors. The third digit represents industry subsector, the fourth digit represents industry group, the fifth digit represents industry, and the sixth digit is U.S., Canadian, or Mexican National specific. For more information, see the U.S. Census Website.
HUC-12 Code
Hydrologic Unit Code (HUC) code assigned by the US Geological Survey used to classify watersheds in the United States and the Caribbean. Code consists of two to twelve digits based on six levels of classification:
The Loading Tool obtains this data element using a Watershed Assessment Tracking and Environmental ResultS (WATERS) web service (OWRAD/PCS_WMERC) which obtains the HUC-12 code from the Natural Resources Conservation Service's Watershed Boundary Dataset. The Watershed Boundary Dataset does not include HUC-12's for all NPDES permits in ICIS-NPDES. As a result the HUC-12 can be blank for some facilities in the Loading Tool database.
Top Chemical
Pollutant name(s), these are specifically associated with chemicals that are reported to EPA's TRI Program.
Direct/Indirect TRI Pounds
For the top chemical for each NAICS code, the annual mass (in units of pounds/year) for direct and indirect discharges. This table does not display chemicals that have a total annual load of zero.
Direct/Indirect TRI TWPE
For the top chemical for each NAICS code, the relative toxicities of different pollutant discharges (in units of TWPE) for direct and indirect TRI. This table does not display chemicals that have a total annual load of zero. For more information about TWPE, see ECHO Frequently Asked Questions.

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