EPA finalizes reconsidered issues in Area Source Boilers Rule

By Katie Fletcher | September 21, 2016

This month, EPA set forth its final rule on the issues for which reconsideration was announced on Jan. 21, 2015 that pertained to aspects of the February 2013 final amendments to the National Emissions Standards for Hazardous Air Pollutants for Area Sources: Industrial, Commercial and Institutional Boilers in the Area Source Boilers Rule.

Amongst the changes, EPA is amending three reconsidered provisions. The provision that pertains to biomass-fired boilers is the one that eliminates further performance testing for particulate matter (PM) for certain boilers based on their initial compliance test. EPA has now finalized an alternative provision to require PM performance testing once every five years when initial compliance tests show that PM emissions are equal to or less than half of the limit instead of totally eliminating further PM performance testing.

In the February 2013 final amendments of the Area Source Boilers Rule, the EPA added a new provision that specifies that further PM emissions testing does not need to be conducted if, when demonstrating initial compliance with the PM emission limit, the performance test results show that the PM emissions from the affected boiler are equal to or less than half of the applicable PM emission limit.

The EPA received a petition asserting that the public lacked opportunity to comment on the new provision, so, in response to the petition, in the Jan. 21, 2015 proposal, EPA solicited comment on the provision, specifically requesting comment and supporting information on the magnitude and range of variability in PM and urban metal hazardous air pollutants (HAP) emissions from individual boilers.

Several commenters agreed with the provision that eliminates further PM performance testing when initial compliance tests show that PM emissions are equal to or less than half of the limit and that requires the owner or operator to continue to comply with all applicable operating limits and monitoring requirements.

Two commenters objected to the provision. One commenter claimed that there are no requirements to prevent the facility from changing the fuel type and fuel mixture from those used in the initial compliance testing and a change in fuel type or mixture could result in an increase in PM emissions. Another commenter asserted that it is arbitrary to conclude that a source that measures low emissions in one test will have emissions below the limit thereafter. The commenter claimed that many boilers burn combinations of fuels of varying proportions (e.g., biomass and coal), and because sources are allowed to change their fuel mix within a given fuel type and to change their fuel supplier without changing subcategories, PM emissions from an individual source are likely to be highly variable.

For the same reasons, these two commenters also objected to the alternative provision that would require less frequent (once every five years) PM performance testing.

Based on its review of the public comments and data available on PM and metallic HAP emissions for which PM serves as a surrogate, the EPA is finalizing the provision that specifies that further PM emissions testing does not need to be conducted for five years if, when demonstrating initial compliance with the PM emission limit, the performance test results show that the PM emissions from the affected boiler are equal to or less than half of the applicable PM emission limit. In such instances, the owner or operator would be required to continue to comply with all applicable operating limits and monitoring requirements.

If the source burns a new type of fuel other than ultra-low-sulfur liquid fuel or gaseous fuels, then a new performance test is required within 60 days of burning the new fuel type. New or reconstructed boilers that commenced construction or reconstruction on or before publication of this final action and that previously demonstrated that their PM emissions were equal to or less than half of the PM emission limit are provided five years from publication of this action before they are required to conduct a performance test unless a new type of fuel, other than ultra-low-sulfur liquid fuel or gaseous fuels, is burned. In that situation, a new performance test is required within 60 days of burning the new fuel type. Boilers with test results that show that PM emissions are greater than half of the PM emission limit are required to conduct PM testing every three years.

EPA concluded that a provision that reduces the frequency of testing, rather than eliminates further testing, is more appropriate and environmentally protective for long-term compliance with the PM emission limit, but still provides compliance flexibility for low-emitting boilers.

A detailed discussion of EPA’s findings is included in the “Response to 2015 Reconsideration Comments for Industrial, Commercial, and Institutional Boilers at Area Sources: National Emission Standards for Hazardous Air Pollutants” located in the docket.