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Frequently Asked Questions - About USEtox

USEtox is a model based on scientific consensus providing midpoint characterization factors for human and freshwater ecotoxicological impacts of chemicals in life cycle impact assessment, developed under the United Nations Environment Program (UNEP) and the Society for Environmental Toxicology and Chemistry, (SETAC) Life Cycle Initiative. USEtox does not represent the latest scientific state of the art, but a scientific consensus defining best application practice as an interface between ever advancing science and a need for stability, parsimony, transparency, and reliability.

The USEtox model operates on two scales; the continental scale and the global scale. The continental scale consists of six compartments, namely urban air, rural air, agricultural soil, natural soil, freshwater, and coastal marine water. The global scale has the same compartmental structure, but without urban air (see figure).

USEtox compartments

The main output of USEtox are interim and recommended characterization factors, which should always be used together. Excluding interim characterization factors is in principle only meaninful for sensitivity analysis in an life cycle assessment study. The model and database include environmental fate, exposure, and effect parameters for human toxicity and freshwater ecotoxicity. Characterization factors are calculated by following three steps:

  1. Environmental fate, where the distribution and degradation of each substance is modelled,
  2. Exposure, where the exposure of humans, animals and plants is modelled, and
  3. Effects, where the inherent damage of the substance is modelled.

USEtox will be constantly improved (by including new chemicals, etc.) and is recommended for comparative chemical toxicity assessment by the European Union, the United States - Environmental Protection Agency, and other organizations. USEtox is increasingly used in a wide range of national and international projects as well as in industrial life cycle assessment studies. For details see Publications.

If you refer to USEtox and/or its characterization factors in general, please cite the following publications:
Rosenbaum, R.K., Bachmann, T.M., Gold, L.S., Huijbregts, M.A.J., Jolliet, O., Juraske, R., Koehler, A., Larsen, H.F., MacLeod, M., Margni, M.D., McKone, T.E., Payet, J., Schuhmacher, M., van de Meent, D., Hauschild, M.Z., 2008. USEtox - The UNEP-SETAC toxicity model: Recommended characterisation factors for human toxicity and freshwater ecotoxicity in life cycle impact assessment. The International Journal of Life Cycle Assessment 13, 532-546.

Hauschild, M.Z., Huijbregts, M.A.J., Jolliet, O., Macleod, M., Margni, M.D., van de Meent, D., Rosenbaum, R.K., McKone, T.E., 2008. Building a Model Based on Scientific Consensus for Life Cycle Impact Assessment of Chemicals: The Search for Harmony and Parsimony. Environmental Science and Technology 42, 7032-7037.

If you refer to USEtox human exposure and/or toxicity modeling, please cite in addition the following publication:
Rosenbaum, R.K., Huijbregts, M.A.J., Henderson, A.D., Margni, M., McKone, T.E., van de Meent, D., Hauschild, M.Z., Shaked, S., Li, D.S., Gold, L.S., Jolliet, O., 2011. USEtox human exposure and toxicity factors for comparative assessment of toxic emissions in life cycle analysis: sensitivity to key chemical properties. The International Journal of Life Cycle Assessment 16, 710-727.

If you refer to USEtox fate and/or freshwater ecotoxicity modeling, please cite in addition the following publication:
Henderson, A.D., Hauschild, M.Z., van de Meent, D., Huijbregts, M.A.J., Larsen, H.F., Margni, M., McKone, T.E., Payet, J., Rosenbaum, R.K., Jolliet, O., 2011. USEtox fate and ecotoxicity factors for comparative assessment of toxic emissions in life cycle analysis: sensitivity to key chemical properties. The International Journal of Life Cycle Assessment 16, 701-709.

The USEtox team intends to regularly publish updated versions of the software as well as updates to model inputs and outputs. Corrections affecting existing characterization factors that are found to be potentially erroneous will be made once per year (corrective updates). Updates based on data, scientific and technical progress that affect existing characterization factors will be made at the maximum once a year, while updates adding new characterization factors, but not affecting existing/published characterization factors can be made anytime (progress-based updates). Further information is given in the full Update procedure document.

The USEtox model supplies a stable method and the version number can be found on the sheet “Version” of the USEtox model file. The latest available USEtox version will always be available in our USEtox Download section.

Following the global consensus-building recommendations of the UNEP/SETAC Life Cycle Initiative's work on Global LCIA Guidance, several USEtox updates are foreseen in the years 2020-2023:

Human Toxicity:


All listed updates are based on global recommendations stated in the Global LCIA Guidance 2016 and 2019 Pellston workshop reports.

UNEP Pellston workshop reports