The US Environmental Protection Agency's Risk Screening Environmental Indicators (RSEI) database is a peer-reviewed, state-of-the-art method for assessing the chronic human health risk posed by industrial toxic releases... The RSEI data are indeed intended for screening and comparative purposes, and PERI uses this feature of the RSEI data in constructing the Toxic 100. By using RSEI data, the Toxic 100 allows comparison between the health risks posed by air pollution released by different companies.