Section 112 of the Clean Air Act (CAA) establishes a two-stage regulatory process for addressing emissions of hazardous air pollutants (HAPs) from stationary sources. In the first stage, section 112(d) requires the Environmental Protection Agency (EPA) to develop technology-based standards for categories of sources (e.g., petroleum refineries, pulp and paper mills, etc.).

In the second stage, EPA is required under section 112(f)(2) to assess the health and environmental risks that remain after implementation of the Maximum Achievable Control Technology (MACT) standards.

If additional risk reductions are necessary to protect public health with an ample margin of safety or to prevent an adverse environmental effect, EPA must develop standards to address these remaining risks.

This second stage of the regulatory process is known as the residual risk stage. For each source category for which EPA issued MACT standards, the residual risk stage must be completed within eight years of promulgation of the initial technology-based standard.

For more information on the rule, visit the regulation page for Pulp and Paper Production (MACT I & III): National Emissions Standards for Hazardous Air Pollutants (NESHAP) for Source Categories.

• Residual Risk Assessment for the Pulp & Paper Source Category (PDF)(550 pp, 9 MB, July 2012)