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Risk-Screening Environmental Indicators (RSEI) Model

Modeling Off-Site Transfers in RSEI

An off-site transfer is the transfer of toxic chemicals in 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.

Off-site transfers are reported to TRI in Form R Sections:

  • 6.1: Discharges to Publicly Owned Treatment Works (POTWs)
  • 6.2: Transfers to Other Off-Site Locations

Definitions for other TRI reporting terms

Transfers to off-site facilities are reported to TRI by the facility transferring the waste. Transferring, or “origin” facilities, report the Resource Conservation and Recovery Act (RCRA) identification number associated with the receiving facility, where possible, and its name and address. Origin facilities are also required to indicate the ultimate disposition of each chemical, according to the categorization below.


Image of industrial equipment at a landfill, representing off-site transfers for disposalDisposal
This category includes various methods of disposal, such as landfills, surface impoundments, and underground injection. Off-site transfers to disposal are not modeled by RSEI, so no scores are available; however, users can look at pounds transferred and RSEI Hazard (pounds times chemical toxicity).


Image of a recycling bin, representing off-site recyclingRecycling
Off-site 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 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 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 recycling. Transfers for recycling are not modeled by RSEI, so no scores are available; however, users can look at pounds transferred and RSEI Hazard (pounds times chemical toxicity).

Image of an industrial furnace, representing off-site energy recoveryEnergy Recovery
A facility can report a toxic chemical as "used for energy recovery" if the chemical was combusted in an industrial furnace (including kilns) or boiler (as defined in the 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. 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. These kinds of transfers are not modeled by RSEI, so no scores are available; however, users can look at pounds transferred and RSEI Hazard (pounds times chemical toxicity).

Image representing off-site treatment of industrial wasteTreatment
Off-site 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 that left the facility boundary for treatment, not the amount that was destroyed at the off-site location(s). In this category RSEI models and produces scores for incineration reported under codes M50 and M54). For the rest of the category, no scores are available; however, users can look at pounds transferred and RSEI Hazard (pounds times chemical toxicity).

Image of a tank at a wastewater treatment plant, representing off-site transfers to POTWsPOTWs
A POTW is a wastewater treatment facility that is owned by a state or municipality. Wastewaters from facilities reporting under TRI are transferred through pipes or sewers to a POTW. Treatment or removal of a chemical from the wastewater depends upon the nature of the chemical, as well as the treatment methods present 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. RSEI models and produces scores for all of the transfers in this category, as long as sufficient modeling data are available; users can also look at pounds transferred and RSEI Hazard (pounds times chemical toxicity).

Each origin facility reports on the facilities that receive their waste, so the same receiving facility may be described differently by different origin facilities, making it hard to determine when multiple facilities are sending waste to the same receiving facility. This problem is especially pronounced in the years before TRI required electronic reporting, which allows origin facilities to select off-site facilities from a known list (they can also input new facilities). POTWs are another category where origin facilities can report the same wastewater treatment plant in different ways, such as, “City water treatment plant,” “West Side Plant,” “City Utility Board,” etc.

RSEI uses approximate text string matching and visual inspection (using satellite maps and internet searches) to increase the match rate for receiving facilities, and decrease the number of unique facilities listed in the off-site database. Reducing the database to as few unique facilities as possible is important when looking at RSEI results by receiving facility; if a receiving facility has more than one entry in the database and the score or hazard gets split between multiple entries, a user looking at only one of those entries will underestimate the potential impact associated with that facility. More information on finding unique receiving facilities.

Incinerators

Incinerators are a special case because there is potential for double-counting of modeled releases. Beginning in 1998, chemical waste handlers (which may include hazardous waste incinerators) were required to report to TRI. Some hazardous waste incinerators may report emissions from incineration of waste transferred from other TRI reporting facilities, who report the same waste as off-site transfers. To minimize the potential for double-counting, RSEI zeroes out the off-site transfers to incineration that meet all three of the following criteria:

  1. Transfer is received by a facility that is a TRI reporter and either:
    1. Is on RCRA list of Incinerators and Cement Kilns, or
    2. Has a primary NAICS code of 562211 (Hazardous Waste Treatment and Disposal);
  2. Transfer is categorized as a transfer to incineration (M50 and M54); and
  3. Transfer was reported after 1997.

While other categories of off-site transfers present similar problems, off-site transfers to incineration is the only category of off-site transfers that RSEI models. In some information products like TRI.net and TRI explorer, the TRI program presents two ways to account for pounds: the gross accounting presents all pounds as reported, while the net accounting is used in certain aggregations, and subtracts certain transfers that may be double-counted. RSEI does not use the TRI program’s net accounting approach. The TRI program’s approach is explained in Box 5 of Factors to Consider When Using TRI Data.

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