UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

REGION 8
 

999 18TH STREET • SUITE 300
 

DENVER, CO 80202-2466
 

http://www.epa.gov/region08
 

MAR I 9 2001 

Ref: 8P-AR 

Margie Perkins, Director
 

Air Pollution Control Division
 

Department ofPublic Health and Environment
 

4300 Cherry Creek Drive South
 

Denver, CO 80246-1530
 

\ Dear Margie, 

This letter is in regards to Colorado's SIP revision for Fort Carson's opacity exemption in 

the Colorado Code ofRegulations, Regulation I. Governor Owens submitted this revision to 

EPA on November 5, 1999. We have done an extensive review ofthis proposed revision and 

have had discussions with your staff as well as with the Army's air quality department at Fort 

Carson. Following our review, we have determined that we can't act on this revision as it is and 

we require further technical analyses so that we may understand the true impacts on the ambient 

air from the smoke obscurant activities. 

Consideration of All Impacts: 

Submitted with the proposed SIP revision, are documents suggesting that the Army plans 

to begin using ~e along with the fog oil in the smoke generators. Since graphite is a 

different substance from fog oil, and all ofthe analyses at this point have only been done to 

determine the impacts from the fog oil, we believe that a further analyses of the use of this 

substance needs to be done. Currently, there is no restriction in Colorado's regulation that would 

restrict the amount of graphite to be used; the 1540 gallons per day is limited to fog oil. In 

addition, the documentation also refers to the smoke pots and colored smoke grenades used 

during the smoke training exercises. These activities also need to be considered in the overall 

analyses since, added together, they could contribute to a more adverse impact to ambient air than 

c.. was described in your analysis. 

Monitoring Analyses: 

We believe that real-time monitoring should be required ofthe Army and conducted 

during smoke training episodes. That is the most accurate way in which to track particulate levels 

and for the Army to be able to stop the smoke training exercises if the particulate levels on the 

monitor are nearing the level ofthe PM NAAQS. We believe that this would be much more 

protective ofthe NAAQS than the requirement included in the presently submitted SIP revision 

oPrinted on Recycled Paper 

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that an observer will be posted during smoke training to monitor whether the smoke is going over 

the site boundary. 

Modeling Issues: 

A major reason for our concern about this opacity exemption is that in the modeling 

studies submitted to us with this revision, it is clear that the smoke cloud from the generators is 

consistently very near state highway 115 at the western border of the Sullivan Park site. Since the 

modeling study didn't address a worst case emissions scenario, including impacts from all smoke 

obscurant activities, much higher concentrations could occur at this location. We find this very 

troublesome. In addition, worst case meteorology conditions may not have been considered. In a 

June 29, 1998 memorandum from Chuck Machovec, of your Technical Services Program, to 

Dave Ouimette, ofthe Stationary Sources Program, Chuck writes that, "...analyses suggest that 

exceedances ofstandards or guideline values could also occur ifgenerators are used for shorter 

periods if there is steady transport toward a nearby site boundary for several hours." Due to these 

two areas ofweakness in the modeling study, we are not assured that there will indeed be no 

potentially hazardous impacts to ambient air and the public from these smoke training exercises. 

Although the rule, as written in Regulation 1, exempts emissions from fog oil smoke and 

other short duration military smokes, which could include any number of materials, including 

graphite, the modeling study is based only on fog oil. Fog oil has a specific composition described 

by the Army, which doesn't include graphite. Because graphite used in the generators could 

cause different impacts than fog oil, the addition ofthis material should also be assessed, including 

a consideration of the density and particle size of graphite. In addition, all other smoke training 

exercises and impacts should be included in the study, including the combined impacts from the 

use of smoke pots and colored smoke grenades during the training activities. 

In order to assess the true impacts of the smoke training exercises on the ambient air, it is 

also essential to know the particle size distribution from the various smoke training activities, 

including the use ofgraphite. In an April 26, 2000 letter from David Sealander ofFort Carson's 

Environmental Compliance Division, to Cindy Rosenberg, of our Air and Radiation Program, the 

Army explained that a monodisperse particle size ofO.6f.lm for fog oil was used in the modeling 

study. That letter explains that in actuality, "...there will be some variability in the particle size 

distribution depending on equipment operability... " It should be possible to put various sizes into 

the model. EPA believes that this would enhance the reliability and credibility of the modeling 

study. 

To conclude our concerns with the modeling study, we have determined that there is a 

deficiency in the modeling to show worst case impacts from all of the smoke obscurant exercises. 

The modeling study should accurately characterize the impacts on the particulate standard in 

terms of all the fog oil and smoke obscurants that are used by the Army. It is important that the 

modeling represent the true worst case scenario, which, in addition to the above, includes 

consideration ofthe worst case meteorology that may occur at the time ofday that smoke training 

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exercises take place. 

Mitigation Procedures: 

The proposed revision to Regulation 1 includes the requirement that, "Smoke generation 

shall cease immediately if such smoke crosses or if such smoke is in danger of crossing the 

boundary ofthe military reservation or if meteorological conditions are expected to change in a 

way that would transport existing smoke plumes across the Installation or Site boundary;..." The 

revision also requires that an observer be posted during the smoke training exercises so that the 

exercises may be, "...halted due to an increased potential for smoke to drift across the Installation 

or Site boundary;... " We fail to see how these requirements can be protective ofthe ambient air 

in the absence of meteorological forecasting. A more appropriate means for avoiding impact in 

the ambient air would be to couple meteorological forecasting with the real-time monitoring 

mentioned above. 

Recordkeeping, Reporting and Public Notification: 

Fort Leonard Wood received a similar opacity exemption from EPA Region VII. The 

permit related to this SIP exemption includes hourly limits on the amount offog oil used in order 

to protect the public from the short-term impacts these activities may create. In order to agree to 

the terms of the exemption, the regional office required the army to commit to community 

awareness ofthe smoke training activities and post people on the roads during the exercises to 

make sure there were no impacts on the public. Fort Leonard Wood is also required to: report 

violations ofthe permit or SIP requirements, conduct monitoring with a QAPP to conform with 

the modeling assumptions and to submit the monitoring data quarterly, have a meteorologist 

conducting forecasts and documenting those forecasts, and do pre-exercise computer modeling. 

We recognize that Regulation 1 does include recordkeeping requirements, however, we feel that 

the above requirements for Fort Leonard Wood should be replicated for Fort Carson in order to 

remain consistent within EPA and to adequately protect the health ofthe public. 

Toxicity Issues: 

S9lvent yellow 33 may be a reproductive toxicant and there is some evidence that it is a 

carcinogen. The National Academy of Sciences has told the Army not to expose the public to this 

substance since the data for assessing its toxicity is inadequate and furthermore it couldn't 

recommend an exposure level due to the lack of data. This substance is used both in the fog oil 

and the smoke pots. Because the Army's and Colorado's analysis didn't include the impacts from 

the hexachloroethane produced during the smoke training, it is impossible to know if there are the 

potential impacts to the pUblic. 

Limiting Fog Oil Burning: 

The changes to Regulation 1 would only include a daily limit on the gallons offog oil 

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burned (1540 gallons) in the generators. It appears that the modeling used to determine this limit 

of 1540 gallons is based on the operation of 7 fog oil generators operating continuously for 4 

hours. Since these activities are short in duration, but cause large impacts, the regulation revision 

should be based on a more specific requirement limiting the number of generators used and the 

timeframe in which that limitation applies. Furthermore, the proposed revision to Regulation 1 

only limits the amount offog oil burned and not the amounts of the other materials that are used. 

There should be a limit placed on everything used during the smoke training episodes for which 

this opacity exemption would apply, including limiting the amount of graphite burned. 

Enforcement of Federally Approved SIP: 

Lastly, we are concerned that prior to this revision to the SIP being federally approved 

and even before this revision was submitted to EPA, Fort Carson was operating under the 

assumption that the AQCC's approval of this exemption constituted federal approval into the SIP. 

This creates enforcement issues with the federally approved SIP. 

We would like to meet with you and your staff to discuss the above listed issues. Please 

contact us to let us know when you are available to meet. If you have further questions, please 

contact me at 303/312-6005 or Larry Svoboda at 303/312-6004, or have your staffcontact Cindy 

Rosenberg at 303/312-6436. 

cc: Doug Lempke, AQCC 

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