B--Development of Statistically Based Quantitative Structure-Toxicity Relationship (QSTR) Models for Predicting the Sub-Chronic Toxicity Benchmarks for a Variety of Chemicals

The first two sentences of the first paragraph of the original synopsis, dated 07/06/05, shall be modified as follows: The U.S. Environmental Protection Agency (U.S.EPA), National Homeland Security Research Center (NHSRC), seeks a contractor to use the experimental sub-chronic toxicity benchmark (in the form of a LOAEL, BMD, or BMDL10) data to develop predictive models to estimate the sub-chronic toxicity of a variety of chemicals through the use of Quantitative Structure-Toxicity Relationships (QSTRs) for both oral and inhalation routes of exposure. The contractor shall develop a separate QSTR model for each of the above-mentioned benchmarks and exposure routes.