TRI and Estimating Potential Risk

The Toxics Release Inventory (TRI) provides data about environmental releases of toxic chemicals from industrial facilities throughout the United States, measured in pounds. The quantity of releases, however, does not indicate the level of health risk posed by the chemicals. Although TRI data can't tell you whether or to what extent you've been exposed to these chemicals, they can be used as a starting point in evaluating potential risks to human health and the environment.

• Is my health at risk because of toxic chemicals in my community?
• How can TRI data help me understand relative risk?
• How can I find out about the toxicity of certain chemicals?
• How is EPA working to minimize risks from toxic chemicals in my community?

Is my health at risk because of toxic chemicals in my community?

TRI data alone cannot answer this question; the human health risks resulting from exposure to chemicals are determined by many factors, as shown in the figure below. TRI contains some of this information, including what chemicals are released from industrial facilities; the amount of each chemical released; and the amounts released to air, water, and land. 

It is important to keep in mind that while TRI includes information on a large portion of the chemicals used by industry, it does not cover all facilities, all toxic chemicals, or all sources of TRI chemicals in communities. For example, potential sources of chemical exposure that are not covered by TRI include exhaust from cars and trucks, chemicals in consumer products, and chemical residues in food and water.

Overview of Factors that Influence Risk

How can TRI data help me understand relative risk?

EPA's Risk-Screening Environmental Indicators (RSEI) model can help you explore potential relative human health risks associated with chemical releases from industrial facilities that report to the TRI Program. RSEI models the route of each chemical release through the environment and the potential human exposure that may result. The model brings together large amounts of complex information and provides easier-to-use results for screening, prioritizing and analyzing trends. The metrics produced by the model can be used to help identify situations of potential concern.

Note that the RSEI model should only be used for screening-level activities such as trend analyses that compare potential relative risk from year to year, or ranking and prioritization of chemicals or industry sectors for strategic planning. RSEI does not provide a formal risk assessment, which typically requires site-specific information, more refined exposure information, and detailed population distributions. For information about the risk assessment process, visit EPA's main risk assessment webpage.

How can I find out about the toxicity of certain chemicals?

Within the RSEI model and other tools, the TRI Program uses relative toxicity weights that describe each chemical’s toxicity relative to other TRI-reported chemicals. The toxicity weights are based solely on human health effects associated with long-term exposure to chemicals, and based on the single most sensitive effect for the pathway (oral or inhalation)—that is, the effect that happens at the lowest dose. Toxicity weights are available for individually listed TRI chemicals and chemical categories. 

For most chemical categories, EPA assumes the most toxic form of the chemical, except for certain categories including chromium and chromium compounds, polycyclic aromatic compounds, and mercury and mercury compounds. Toxicity can be used to measure the potential hazard (pounds multiplied by toxicity weights) of the chemical. To learn more, refer to the RSEI Toxicity Weights webpage. These weights were developed from EPA's Integrated Risk Information System (IRIS) and other data sources. 

Other resources that have information about TRI chemicals and the effects of exposure on human health and the environment include:

• TRI Chemical Hazard Information Profiles (TRI-CHIP): Downloadable database containing toxicity information for chemicals on the TRI list.
• ATSDR's Toxic Substances Portal: Resources developed by the Agency for Toxic Substances & Disease Registry. Includes fact sheets that answer common questions about exposure to hazardous substances.

How is EPA working to minimize risks from toxic chemicals in my community?

EPA works with state and tribal partners to:

• regulate how and to what extent facilities store, use, handle, release and dispose of toxic chemicals;
• encourage facilities to prevent or reduce pollution at the source; and
• publish TRI data to create a strong incentive for companies to improve environmental performance.

In general, industrial facilities that operate in compliance with environmental regulations have controls in place that reduce the potential risks their operations might pose to human health and the environment.