The Tiered System of Regulation

When chlorinated organic compounds are burned, hydrogen chloride and chlorine gas form. These substances pose health risks and contribute to the formation of acid rain. Hydrogen chloride and chlorine gas emissions and metal emissions are regulated under a tiered set of standards, as follows:

• Tier I requires the lowest level of monitoring. It requires that the waste feed rate is adjusted. One-hundred percent of the pollutants are expected to escape into the environment.
• Tier II requires increased monitoring to verify that pollutants have not escaped into the environment. The pollutants may have been contained within the bottom ash, recovered as products, or collected by air pollution control devices.
• Tier III requires the most monitoring of the three tiers. This approach uses air dispersion modeling to prevent toxic emissions from posing threats to human health and the environment.

Air dispersion modeling uses computer simulations to build models to estimate how air pollutants disperse in the atmosphere. These models are used to predict where pollutants will travel and how they will react in the atmosphere.

To learn more about RCRA visit our RCRA Hazardous Waste Safety Online Training web page.