Toxic Release Inventory Analysis

Because chemicals differ enormously in how harmful they are. A large release of a relatively benign solvent can dwarf, in pounds, a small release of a potent carcinogen, even though the carcinogen poses far greater risk. Analyzing raw poundage therefore lets high-volume, low-hazard chemicals dominate the picture and can badly mismeasure who actually bears risk. The RSEI approach used by Ash and Fetter multiplies each chemical's quantity by a toxicity weight, producing a hazard-relevant burden measure that supports defensible conclusions about exposure and equity.

RSEI, the EPA's Risk-Screening Environmental Indicators model, turns TRI's raw release reports into a screening-level estimate of relative exposure burden. It applies chemical-specific toxicity weights and a dispersion model that spreads each facility's releases across the surrounding area according to distance, stack height, and prevailing winds, and it overlays population. The output is a toxicity- and exposure-weighted burden score for small areas that is far more meaningful for equity analysis than emission counts, though it remains a relative screening estimate rather than a measured concentration.

TRI is self-reported and only covers facilities above reporting thresholds, so it understates total releases and misses smaller sources entirely. It also captures only industrial point sources, so pollution from traffic, area sources, and small businesses, which can dominate burden in some communities, is invisible to it. Finally, even with toxicity weighting and dispersion modeling, the results are exposure surrogates rather than measured ambient concentrations or health outcomes. Analysts should treat TRI burden scores as a strong but partial screening measure and triangulate with monitoring data where stakes are high.