Volume 16, Number 2
A Gossman Consulting, Inc. Publication
February 2011

BACT for GHG (Green House Gas) from Cement Plants – A Critical Error in the EPA BACT Example


David Gossman


EPA recently released a series of videos of slide presentations on Best Available Control Technology (BACT) analysis for GHG for various industries. One of the BACT analysis examples provided is for a cement plant. There are significant errors in this analysis that would likely negatively impact GHG emissions and provide a further barrier to modernization and construction of new cement plants in the US.


EPA’s BACT analysis example contains many of the basic components that one might expect. These include alternative fuel options, modern design, maintenance, computer control and an analysis of the potential for sequestration. Most of these have expected and logical outcomes based on the currently available technology. There are two issues that are raised with potential errors in the analysis that are likely to have the opposite-to-intended effect. One of these is relatively minor, the other is major.

The minor issue is that of location. The example cement plant is assumed to be providing cement in a local market, that is with minimal transportation GHG emissions.  While this seems reasonable on the surface, recent changes to EPA MACT requirements for cement plants are likely to move some new cement plants to locations quite distant from their markets to either obtain raw materials that will allow cement plants to meet the new MACT emission restrictions or to move the plant outside of the US altogether to avoid these restrictions. Either moving a plant to a location with “cleaner” raw materials or out of the country will have potentially large negative impacts on GHG emissions.

The second issue is large and troubling in nature. EPA, in this BACT example for a cement plant, proposes to require the plant to produce a blended cement via the substitution of at least 5% fly ash in the finished product.


For those not familiar with the cement industry, the requirement for blended cement might appear logical and desirable. Quite the opposite is the case. It has to be understood that Portland cement is manufactured to exacting standards set down by ASTM. ASTM standards are required to be honored during the process of developing and enforcing EPA regulations by virtue of well established government policy, directives and legislation. To put it simply, cement that has 5% or more fly ash is no longer Portland cement but is instead a blended cement, both being clearly defined terms by ASTM. EPA is literally requiring the plant to manufacture a different product as part of this BACT analysis, something that is clearly prohibited by the Clean Air Act.

Further, blended cements shipped from cement plants in most areas of the US simply do not exist. For example, there were a total of 2,158 metric tons of blended cement shipped in Illinois during October 2010 compared with 294,221 metric tons of Portland cement. No blended cement was shipped in the Chicago market during this same time period. Blending of fly ash and other materials after the manufacture of Portland cement is done at the end-use sites, that is, at ready-mix plants. At those sites these types of blends can vary from 0% substitution to 50% or more substitution depending on the end-use specifications, which are quite often set by other government agencies. If these ready-mix plants were required to accept a preblended cement from cement plants it would severely restrict their ability to meet market requirements and restrict their ability to blend cements mixtures that maximize the use of byproducts such as fly ash and also minimize overall GHG emissions.

In most cases the maximizing of the use of blended cements is also a matter of scale. Smaller ready-mix plants are in a far better position to blend the relatively small batches of finished product and maximize the use of alternative cementitious materials than the much larger cement plant. Even under a theoretical best case analysis EPA has done nothing in this BACT analysis to reduce GHG emissions – they have just shifted the facility at which that activity is already accomplished.


Any cement company faced with the alternative of making a product for which there is no market vs. moving production outside of the country is far more likely to choose the latter than the former. The net result is the loss of American jobs and increased emissions of GHG.

If the example GHG BACT analysis for cement plants provided by EPA is a typical example then there may be significant errors in other analyses in other sections of these EPA video/presentations.

EPA’s attempt to use the Clean Air Act to control GHG emissions could have the opposite-to-the intended effect. By looking at specific facilities and point sources it is quite likely that EPA requirements will push GHG emissions off-site or even out of the country; with the added impact of actually increasing GHG emissions. Clearly, that is the case in the example given and, because of the unsuitability of the Clean Air Act as a mechanism for controlling GHG emissions, is likely to continue into the future so long as EPA pursues this approach.