On Friday, EPA proposed certain revisions to its rule on air emissions from boilers and commercial and industrial solid waste incinerators (CISWI). As with other major rules under development in the past few years, EPA has taken fairly substantial steps to limit the reach of the rule to those boilers and CISWI that are of greatest concern. Without engaging in formal cost-effectiveness analysis, EPA has sought to make the rule as cost-effective as possible.

As with most of EPA’s big rules, it is too complex to be summarized in a blog post. EPA’s summary fact sheet is here. Very briefly, the rule exempts 86% of industrial boilers and subjects most other boilers to work practice standards rather than emission limits. For those boilers subject to the emission limits, the new rules relaxed limits for CO, PM, and most metals, but increased the stringency for mercury and acid gases.