Common TRI Terms

This webpage explains the terms that EPA uses to describe toxic chemical releases and other waste management quantities reported under the TRI Program.

Releases

A "release" refers to different ways that toxic chemicals from industrial facilities enter the air, water, and land.
Releases include spilling, leaking, pumping, pouring, emitting, emptying, discharging, injecting, escaping, leaching, dumping, or disposing into the environment.
For TRI purposes, "release, " "emission," and "discharge" are used interchangeably.

An image of a smokestack, a water discharge pipe, and waste rock at a mine.

On-site Releases and Other Management of TRI Chemicals in Waste

Air Releases

Point source (also called "stack emissions"): Air releases that occur through confined air streams, such as stacks, ducts or pipes.
Fugitive: Releases to air that don’t occur through a confined air stream. Includes equipment leaks, releases from building ventilation systems and evaporative losses from surface impoundments and spills.

Surface Water Discharges

Includes discharges to streams, rivers, lakes, oceans and other bodies of water. These discharges come from contained sources, such as industrial process outflow pipes or open trenches. Facilities must identify the name of each water body into which the TRI chemical is being discharged. Releases of TRI chemicals due to runoff, including stormwater runoff, are also reportable in this category.

Land Releases

Includes disposal of toxic chemicals in:

surface impoundments (uncovered holding areas used to volatize and/or settle waste materials)
underground injection wells (in which fluids are injected below the lowermost underground source of drinking water)
RCRA Subtitle C landfills (in which wastes are buried)
other landfills (in which wastes are buried)

Also includes:

land treatment/application farming (management techniques in which a waste containing a TRI-listed chemical is applied to or incorporated into soil)
other land disposal methods (such as waste piles)
other releases to land (such as spills or leaks)

Total On-site Disposal or Other Releases

This is the sum of air emissions, surface water discharges, and land disposal at a facility.

Recycling

Includes a variety of methods through which toxic chemicals in waste can be recovered, such as solvent recovery and metals recovery. To be reported as recycling under TRI, the chemicals or the waste containing the chemicals must undergo a recovery step prior to being used again, such as removing impurities from a solvent. The choice of the recycling method depends on the chemical. Once they have been recycled, these chemicals may be reused at the facility or made available for use in commerce.

Energy Recovery

A facility can report a chemical as "used for energy recovery" if the chemical was combusted in an industrial furnace (including kilns) or boiler (as defined in TRI regulations) to generate heat or energy for use at the facility. This process can be used for toxic chemicals of significant heating value (>5000 BTUs) in wastes. Incineration of a chemical that is not of significant heating value or in a device that does not meet the regulatory definition of an industrial furnace or boiler is not considered to be used for energy recovery.

Treatment

Includes a variety of methods through which toxic chemicals in waste may be treated, such as biological treatment, incineration, and chemical oxidation. These methods typically result in varying degrees of destruction of the toxic chemical. Facilities report the quantity of the toxic chemical destroyed in on-site waste treatment operations.

Off-site Transfers of TRI Chemicals in Waste

An off-site transfer is the transfer of chemical-containing waste to a facility that is geographically or physically separate from the facility reporting under TRI. Chemicals reported to TRI as transferred are sent to off-site facilities for the purposes of recycling, energy recovery, treatment, or disposal. The amounts reported represent a movement of the chemical away from the reporting facility. Except for off-site transfers to disposal, these amounts do not necessarily represent entry of the chemical into the environment.

Transfers Off Site for Disposal

Includes various methods through which toxic chemicals can be disposed, such as landfills, surface impoundments, and underground injection at a receiving facility. Off-site transfers to disposal are a type of off-site release. Facilities report the quantity of the toxic chemical that left the facility boundary for the purpose of disposal, not the actual amount disposed of at the off-site location(s).

Transfers Off Site for Recycling

Includes a variety of methods through which toxic chemicals in waste can be recovered, such as solvent recovery and metals recovery. To be reported as off-site recycling, the chemicals or the waste containing the chemicals must be transferred to a receiving facility for recovery purposes such as removing impurities from a solvent.

The choice of the recycling method depends on the toxic chemical. Once they have been recycled, these chemicals may be returned to the originating facility for further processing or made available for use in commerce. Facilities report the quantity of the toxic chemical that left the facility boundary for the intended purpose of recycling, not the amount that was recycled at the off-site location(s).

Transfers Off Site for Energy Recovery

Includes the combustion of toxic chemicals for the purpose of energy recovery at an off-site location or the transfer to a waste broker for this purpose. TRI regulations define energy recovery as the combustion in an industrial furnace (including kilns) or boiler to generate heat or energy for use at the facility using toxic chemicals of significant heating value (>5000 BTUs) in wastes.

Incineration of a chemical that is not of significant heating value or in a device that does not meet the regulatory definition of an industrial furnace or boiler is not considered to be used for energy recovery. Facilities report the quantity of the toxic chemical that left the facility boundary for energy recovery, not the amount combusted at the off-site location(s).

Transfers Off Site for Treatment (Excluding POTWs)

Includes a variety of methods through which toxic chemicals in waste may be treated, such as biological treatment, incineration, and chemical oxidation at the receiving facility. These methods typically result in varying degrees of destruction of the toxic chemical. Facilities report the quantity of the toxic chemical that left the facility boundary for treatment, not the amount that was destroyed at the off-site location(s).

Transfers to Publicly Owned Treatment Works (POTWs)

A POTW is a wastewater treatment facility that is owned by a state or municipality. Wastewaters from facilities are transferred through pipes or sewers to a POTW. Facilities report the quantity of TRI-covered chemicals present in the wastewater. They also indicate the method(s) by which the chemical is likely to be disposed of or treated at the POTW(s).

Treatment or removal of a chemical from the wastewater depends upon the nature of the chemical, as well as the treatment methods used at the POTW. Not all TRI chemicals can be treated or removed by a POTW. Some chemicals (such as metals) may be removed, but are not destroyed and may be disposed of in landfills or discharged to receiving waters.

Other Common TRI Terms

Source Reduction

Source reduction (also referred to as pollution prevention) includes activities that eliminate or reduce the use of chemicals and the creation of chemical waste. For example: substitution of raw materials, reformulation or redesign of products, equipment or technology modifications, and process or procedure modifications. Facilities report newly implemented source reduction activities, meaning those that were implemented, in whole or in part, during the TRI reporting year.

Production-Related Waste Managed

The quantity of chemical waste generated at a facility as a result of normal, routine production processes and reported as managed. Production-related waste managed is the sum of on-site releases, other on-site waste management, and off-site transfers minus quantities from non-routine, one-time events. Waste management consists of handling waste through recycling, energy recovery, treatment, or release/disposal.

Non-Production-Related Waste Managed

The quantity of waste containing TRI chemicals resulting from one-time, non-routine events, rather than from standard production activities. Examples include spills and catastrophic events, such as natural disasters, that result in incidental waste generation that must then be disposed of or managed in another way. Non-production-related waste quantities are often reported as on-site releases, other on-site waste management (e.g., incineration), or transfers off site. These quantities are included in a facility’s total disposal or other releases and overall waste management quantities.

Total Waste Managed

The quantity of production-related waste managed at the facility plus the quantity of non-production-related waste generated at the facility.

Total Disposal or Other Releases

This is the sum of on-site disposal or other releases and off-site disposal or other releases. This quantity includes any accidental, one-time releases.