UNITED STATES ENVIRONMENTAL PROTECTION AGENCY


Office of Air Quality Planning and Standards 


Research Triangle Park, North Carolina 27711


MAR 1985


MEMORANDUM


SUBJECT: Applicability Determinations for Columbian Chemical Company


FROM:	 Darryl D. Tyler, Director


Control Programs Development Division (MD-15)


TO:	 Thomas Maslany, Chief


Air Enforcement Branch, Region III (3AM20)


This is a formal documentation of responses to your January 21,1985,


memorandum requesting prevention of significant deterioration (PSD) appli­


cability determinations relating to three different proposed situations


at the Columbian Chemical Company (CCC) in West Virginia. As you know, we


provided verbal responses to your concerns during our telephone conversations 


of February 6,8,19, and 22 with Vern Butler. The latter two conversations


also responded to Vern Butler's memorandum to you titled "PSD Application 


for the Columbian Chemical Company," which Vern shared with us February 12.


Our responses are based on the EPA PSD rules contained in Part 52, 


since it is our understanding that this source is a major source in an SO2


attainment area. Please note that this memorandum constitutes only initial


guidance on which items might be pursued with West Virginia and CCC. If a


decision is made to initiate one of these approaches, a number of policy 


and technical issues would need to be resolved, many of them in conjunction


with the Monitoring and Data Analysis Division (MDAD).


Item A


The CCC fires an existing boiler and dryers with natural gas, which emits


almost no S02; it proposes to burn 25 percent of the carbon black production


process off gases, which contain H2S, in place of the natural gas. The process


gas currently is exhausted through baghouses to stacks. H2S, CO, and acetylene


emissions would decrease substantially, while S02 emissions (from oxidation


of the H2S) would increase substantially. CCC has asked if the H2S reduction


can be credited toward the S02 increase.


Reductions in one pollutant generally are not creditable toward increases


in another pollutant, even if both pollutants share certain characteristics,


such as, in this case, both H2S and SO2 being sulfur compounds. However, it 


is our understanding (from Vern’s February 12 memorandum) that most of the H2S


oxidizes to S02 in the atmosphere within 17 hours and that under certain


conditions as much as 66 percent of the H2S can be converted to SO2 within


30 minutes. Therefore, to the degree that H2S which converts to S02 affects

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S02 concentrations in the ambient air surrounding the facility, it is 


possible that H2S emissions reductions could decrease S02 concentrations


in the ambient air. It should be noted, however, that application of this


concept would also result in the modeling of sources to determine S02 


impacts resulting from H2S emissions increases as well as decreases. This


has not been EPA's policy, and we would need to investigate this in terms of


a policy decision which would have to be handled as a rule change, since 


the only conversions officially recognized (VOC to ozone and NO to N02) are


embodied in the regulations. This will not be either an easy or simple


approach for the source to take, and we strongly recommend that resources 


not be invested in attempting this. Even preliminary approval of the


technical aspects of this approach would require the agreement of MDAD


experts and others on the appropriate models, meteorological conditions, 


H2S-to-S02 conversion rates, receptor sites, impacts at each site, and


emissions equivalent to impacts at each site.


As we have discussed, a different approach may be to determine whether


use of process gas in the existing boiler constitutes a modification. If 


the boiler was capable of accommodating the process gas on January 6,1975,


and has continued since then to be able to accommodate the process gas


without physical changes (including the burners), then the use of process 


gas containing H2S would not constitute a modification even though S02


emissions would increase. It would, however, still consume increment.


Item B


As an alternative to use of the existing boiler, CCC has proposed


replacing the existing boiler with a new, larger boiler, burning 50-60 percent


of the process gas rather than 25 percent. The larger boiler would allow


expansion of the facility, increasing employment in this depressed area, 


while reducing further the H2S odor problem.


Naturally, S02 emissions would increase proportionally. Replacement 


of the existing boiler with a new larger boiler will be subject to PSD if the


emissions increase of at least one of the regulated air pollutants emitted 


is significant. In addition, the new boiler may be subject to new source


performance standards (NSPS).


There are separate NSPS for electric utility and steam generating


boilers. Note that NSPS applicability is based on the size and function


of the new unit, while PSD applicability is based on whether the increase


in emissions would be significant. If the fuel changes (e.g., if only 


natural gas were used in the old boiler as opposed to a mix of process


off gas and natural gas for the new boiler), then there may be new pollutants


to consider under PSD.


Item C


The CCC has proposed to purchase property on which modeling shows the


and CO are being exceeded as a means of preventing violations 


of these NAAQS. They would restrict general public access to this land so


NAAQS for S02

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that, under EPA's definition of "ambient air," air above the property would


not be considered "ambient air" and therefore no NAAQS violations would 


occur.


There is no formal rule or policy at this time that addresses a situation


where a source purchases and restricts access to property on which national


ambient air quality standards (NAAQS) violations would occur as a means of


"complying" with the NAAQS. However, like the other dilution techniques, 


such as the use of higher than necessary stacks, this method of attainment


is not considered desirable by EPA because it does not reduce the total


atmospheric burden of a pollutant and may be inconsistent with Section 123


of the Clean Air Act.


In addition, there are practical and policy constraints. First, the


ambient air definition is more complex than it appears, because the definition


of "general public" changes depending on the source being considered. The 


best way to explain this is by the following examples, which reflect a policy


that OAQPS advocates, but that is still being discussed with OGC.


Assume a source, Plant X, restricts access to its site, Site X. From


Plant X’s point of view, the general public is everyone except Plant X


employees, who are of course allowed access to Site X. Therefore, the 


impacts of Plant X’s emissions on Site X are not considered, but impacts


outside Site X are.


Now assume the owner of a Site Y near Plant X restricts access to


Site Y. Does this mean that Site Y's air is no longer ambient air and that


Plant X’s emissions impact on Site Y need no longer be considered? No, 


because from Plant X’s point of view, the people allowed access to Site Y 


are still part of the "general public."


Now assume that Plant X purchases and restricts access to a different


Site Z near, but not contiguous to, Site X. Is the impact of Plant X’s


emissions on Site Z considered in determining NAAQS exceedances? This is a


policy question that would have to be resolved.


Second, the amount of land that must be acquired to ensure nonexceedance


of NAAQS under a great variety of meteorological conditions may be much 


larger than the source has initially envisioned. Finally, publicly accessible


areas such as highways and rivers may show violations of NAAQS during modeling,


yet prove impossible to purchase.


As a final comment, I empathize with a desire on the part of all parties


to alleviate the problems resulting from H2S emissions at the existing


facility. We are prepared to assist in any way possible in resolving this


situation. However, it has been our experience that even successful attempts


to depart from or avoid routine PSD permit procedures, such as the proposal 


to offset S02 increases with H2S decreases, often result in higher costs and


longer delays than simply applying for the permit in the first place, despite


the control technology, impact analyses, and other requirements. If an


expansion is planned, Columbian Chemical should strongly consider applying

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for a PSD permit and planning to meet PSD requirements rather than pursuing


more complicated approaches.


Please feel free to contact Gary McCutchen (629-5591) if you have any


questions regarding these determinations.


cc:	 R. Bauman


D. Cantor


T. Helms


G. McCutchen 


R. Rhoads


W. Stevenson 


M. Trutna