** Quantities of metals reported as transferred off-site for sewage, treatment, or energy recovery are included in the "Off-site Disposal" category, since these metals may be captured and removed from waste and disposed of in landfills, or by other methods. This approach recognizes the physical nature of metals and the fact that they are not likely to be destroyed through treatment.
The data are taken from the US Toxics Release Inventory, the Canadian National Pollutant Release Inventory (NPRI), and the Mexican Registro de Emisiones y Transferencia de Contaminantes (RETC). Each country has its own list of mandatory pollutants. Reporting thresholds for pollutants, sectors and facilities also vary. For details, see Understanding Taking Stock.
The national PRTR datasets are constantly evolving, as facilities revise previous submissions to correct reporting errors or make other changes. For this reason, the three countries 'lock' their data sets on a specific date and use the 'locked' data for annual summary reports. Each year, the countries issue revised databases that cover all reporting years. The CEC follows a similar process. For the purposes of this database, the NPRI dataset from December 2018, the TRI Basic Data Plus dataset from April 2019 and the RETC dataset from December 2018 were used. Readers can visit the national PRTR websites to see if any changes to the data have occurred.
Industries:
- For information about reporting sectors and NAICS codes, see Important Note about Industry Sector (NAICS) Codes.
Each country requires PRTR reporting by facilities in specific industrial sectors or undertaking specific industrial activities. Click here for more information.
Canada, Mexico and the United States have adopted the North American Industry Classification System (NAICS), whose codes are used to categorize the industrial activities of a facility. Although there is some variation among the three countries in the subsector categorizations and codes used, the breakdown of industrial sectors into general categories is the same:
| NAICS code | Industry |
| 11 | Agriculture, forestry, fishing and hunting |
| 21 | Mining, quarrying and oil and gas extraction |
| 22 | Utilities (electricity, water and gas distribution) |
| 23 | Construction |
| 31/32/33 | Manufacturing |
| 41/42/43 | Wholesale trade |
| 44/45/46 | Retail trade |
| 48/49 | Transportation and warehousing |
| 51 | Information and cultural industries |
| 52 | Finance and insurance |
| 53 | Real estate and rental and leasing |
| 54 | Professional, scientific and technical services |
| 55 | Management of companies and enterprises |
| 56 | Administrative and support, waste management and remediation services |
| 61 | Educational services |
| 62 | Health care and social assistance |
| 71 | Arts, entertainment and recreation |
| 72 | Accommodation and food services |
| 81 | Other services (except public administration) |
| 91/92/93 | Public administration |
PRTR reporting requirements are based in part on the industrial activity undertaken within a facility, and not only the industry code assigned to that facility. Therefore, not all facilities within a given sector might have to report. For example, within the economic sector that includes dry-cleaning only those facilities undertaking the actual dry-cleaning process, and not clothing drop-off points, might be required to report. Another example is a food processing plant that is required to report because it has its own power plant to generate electricity.
Readers should also note that facilities with similar activities can report under different, or multiple, NAICS codes, depending on the activities undertaken at the facility.
Taking Stock Online provides data at the 3-, 4- and 5-digit NAICS code level. In some cases, the North American Industry Classification System (NAICS) codes differ among the three countries. For example, the code for Wholesale Trade is 41 in Canada, 42 in the United States and 43 in Mexico. When querying data for an industrial sector whose code begins with any of the 2 digits below, the results returned might include only partial data. Therefore, you might also wish to consult the data reported under the corresponding codes provided.
| Industrial Sector Name | Corresponding Codes in each Country (for the series starting with the 2 digits indicated) | ||
| Canada | Mexico | United States | |
| Wholesale Trade | 41 | 43 | 42 |
| Retail Trade | 44, 45 | 46 | 44, 45 |
| Public Administration | 91 | 93 | 92 |
Pollutants:
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Units of Measurement:
- Values reported in pounds are converted to kilograms using a conversion factor of 2.205
- Values reported in tonnes are converted to kilograms using a conversion factor of 1000
- Certain pollutants, such as metals, are grouped in Taking Stock (e.g.: "lead and/or its compounds"). Therefore, no CAS number is assigned to the group.
- For NPRI, facilities reporting an on-site release of less than one tonne (with exceptions) are not required to report the specific medium of the release (e.g., to air, water). Therefore, the “total on-site release” amount might not equal the sum of the individual on-site release categories.
- View the List of Pollutants Reported to the North American PRTRs.