CEC - Taking Stock: Overview of PRTR Reporting Requirements

The pollutants subject to national PRTR reporting requirements are listed because they meet certain criteria for chemical toxicity and the potential for risk to human health and the environment. Each PRTR system covers a specific list of substances: NPRI spans over 300 pollutants, TRI approximately 600 and RETC 104.

As of April 2006, the Chemical Abstracts Service (CAS) listed more than 27 million chemical substances and identified more than 239,000 of them as regulated or covered by chemical inventories worldwide.

Facilities report the amounts of each pollutant they have released to the environment at their own location (on site). They also report how much of the substance was sent off-site for disposal, or transferred for recycling or other waste management. Pollutant-based reporting thresholds exist, and certain pollutants have lower reporting thresholds due to their greater potential for risk to human health and the environment. In general, the PRTR pollutant thresholds are as follows:

For Canada's NPRI and the US TRI, a facility must report if it manufactures, processes, or otherwise uses (e.g., in cleaning industrial equipment) 10,000 kilograms (NPRI) or 11,340 kilograms (TRI) of a listed pollutant.
Mexico's RETC has both an "activity" threshold and a "release" threshold. A facility must report if it meets or exceeds either threshold. The RETC "activity" threshold is typically either 2,500 kilograms or 5,000 kilograms, depending on the substance; the typical "release" threshold is 1,000 kilograms.

For more info, see Mandatory pollutants common to at least 2 of the 3 North American PRTRs [Excel - 85KB].

In order to provide more information about PRTR pollutants, the Taking Stock report and online database also categorize them as follows:

Known or suspected carcinogens, based on the World Health Organizations' International Agency for Research on Cancer (IARC) and California's Office of Environmental Health Hazard Assessment (OEHHA) Proposition 65 list
Developmental or reproductive toxicants, based on California's Proposition 65 list
Persistent, bioaccumulative and toxic (PBT) substances, which have properties that render them a long-term environmental and health threat, even in small quantities
Metals: Metals occur naturally, but human activities such as mining and smelting enlarge their proportions in the environment. The toxicity of certain metals and their compounds can depend on the forms they take in the environment. Many metals are also considered to be PBT substances.

Toxic Equivalency Potentials (TEP) for Air and Water Releases

Toxic Equivalency Potentials (TEPs) indicate the relative human health risk associated with a release of one unit of a pollutant, compared to the risk posed by the release of one unit of a reference substance. TEPs are calculated using the CalTOX model, developed by California regulatory agencies. TEPs are one of many different screening tools, each of which is based on a series of assumptions, thus yielding different results.

Readers should note that the TEP analysis is limited in that a release does not directly correlate to actual exposures or levels of risk. In addition, not all of the substances have an assigned TEP (information on their toxicity or exposure potential may be missing). While these pollutants are not ranked by TEP, they should not be assumed to be without risk. Other types of releases not ranked by TEP (e.g., land) should also not be assumed to be without risk.

TEPs are available only for air and water releases. The reference chemical for carcinogens is benzene and the reference chemical for non-carcinogens is toluene. In the Taking Stock report and database, the TEP weight is multiplied by the amount of release to provide a score for each pollutant. The TEPs for Taking Stock have been taken from the Scorecard website.

Which Industries Report?

Each country requires PRTR reporting by facilities in specific industrial sectors or undertaking specific industrial activities.

In Canada, all facilities that meet reporting thresholds and requirements report to the NPRI, with the exception of a few resource-based sectors and certain activities such as research laboratories.
In Mexico, all industrial sectors regulated under federal law are required to report to the RETC, along with facilities in other sectors that engage in activities subject to federal regulation. These include facilities that use boilers, transfer hazardous wastes, or discharge into national water bodies.
In the United States, TRI requires reporting by federal facilities, most manufacturing facilities and industries that service manufacturing facilities (e.g., electric utilities and hazardous waste management facilities). A few resource-based sectors, such as oil and gas extraction, are exempt from reporting.

North American Industry Classification System

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. NAICS codes were established in 1997 and since 2006 they have been incorporated into PRTR reporting to replace the standard industrial classification (SIC) codes used by each country. 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. For more information about the implementation of the NAICS system in each country, see:

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.

Employee Thresholds

Both NPRI and TRI have an employee threshold, generally corresponding to the equivalent of 10 full-time employees (with some exceptions for pollutants or certain types of facilities). Mexico's RETC does not have an employee threshold.

More information on reporting instructions is available on the NPRI, RETC and TRI websites: