# ___ 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 AirPollution Control Division Department ofPublic Health and Environment 4300 Cherry Creek Drive South Denver, CO 80246-1530 

# \ DearMargie,
This letter is in regardsto 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 staffas 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 ofAll Impacts: Submitted with the proposed SIP revision, are documents suggesting thatthe 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 ofthe use ofthis substance needs to be done. Currently, there is no restriction in Colorado's regulation that would restrict the amount ofgraphite 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 trackparticulate levels and for the Army to be able to stop the smoke training exercises ifthe particulate levels onthe monitor are nearing the level ofthePMNAAQS. We believe thatthis would be much more protective oftheNAAQS than the requirement included in the presently submitted SIP revision 

# o Printed on RecycledPaper

... .. 

## ._---­that an observerwill be posted during smoke training to monitorwhetherthe 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 tous with this revision, it is clearthat the smoke cloud from the generators is consistently very near state highway 115 at the western border ofthe 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 havebeen considered. In a June 29, 1998 memorandum from ChuckMachovec, ofyour Technical Services Program, to Dave Ouimette, ofthe Stationary SourcesProgram, Chuckwrites that, "

...analyses suggest that exceedances ofstandards or guideline values could also occur ifgenerators are used for shorter periods ifthere is steady transport toward a nearby site boundaryfor several hours." Duetothese 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 ofmaterials, 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. Becausegraphite used in the generators could cause different impacts than fog oil, the addition ofthis material should also be assessed, including a consideration ofthe density and particle size ofgraphite. In addition, all other smoketraining exercises and impacts should be included in the study, including the combined impacts from the use ofsmoke pots and colored smoke grenades during thetraining activities.
In orderto assess thetrue impacts ofthe smoke training exercises onthe 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, ofourAir and Radiation Program, the Army explained that a monodisperse particle size ofO.6f.lm for fog oil was used in the modeling study. Thatletter explains that in actuality, "

...there will be some variability in the particle size distribution depending on equipment operability

..." 

### It should bepossible to put various sizes into the model. EPAbelieves thatthis would enhance the reliability and credibility ofthe 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 ofthe smoke obscurant exercises. Themodeling study should accurately characterize the impacts on the particulate standard in terms ofall the fog oil and smoke obscurants that are used by the Army. Itis 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

2exercises take place.



### Mitigation Procedures: The proposed revision to Regulation 1includes the requirement that, "Smoke generation shall cease immediately ifsuch smoke crosses or ifsuch smoke is in danger ofcrossing the boundary ofthe military reservation orifmeteorological conditions are expected to change in a way that would transport existing smoke plumes across theInstallation or Siteboundary;

..." 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;

..." Wefail to see howthese requirements can be protective ofthe ambient air in the absence ofmeteorological 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: FortLeonard Wood received a similar opacity exemption from EPARegion 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 agreeto the terms ofthe 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. FortLeonardWood is also required to: report violations ofthe permit or SIP requirements, conduct monitoring with a QAPP to conformwith the modeling assumptions and to submit the monitoring data quarterly, have a meteorologist conducting forecasts and documenting thoseforecasts, and do pre-exercise computer modeling. We recognize thatRegulation 1 does include recordkeeping requirements, however, we feel that the above requirements for FortLeonardWood should be replicated for Fort Carson in orderto remain consistent within EPAand to adequately protect the health ofthe public.



### Toxicity Issues: S9lventyellow 33 may be a reproductive toxicant and there is some evidence that it is a carcinogen. TheNational Academy ofSciences has told the Army not to expose the public to this substance since the datafor assessing its toxicity is inadequate and furthermore it couldn't recommend an exposure level due tothe lack ofdata. This substance is used both in the fog oil and the smoke pots. Becausethe Army's and Colorado's analysis didn't include the impacts from the hexachloroethane produced during the smoke training, it is impossible to know ifthere are the potential impacts tothe pUblic.



### Limiting Fog Oil Burning: The changes to Regulation 1would only include a daily limit onthe gallons offog oil

3burned (1540 gallons) in the generators. Itappears that the modeling used to determine this limit of 1540 gallons is based on the operation of7 fog oil generators operating continuouslyfor 4 hours. Since these activities are short in duration, but cause large impacts, theregulation revision should be based on a more specific requirement limiting the number ofgeneratorsused 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 ofthe 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 ofgraphiteburned.

Enforcement ofFederally Approved 

### SIP: Lastly, we are concerned that priorto this revision to the SIP being federally approved and evenbefore this revision was submitted to EPA, Fort Carson was operating under the assumption thatthe AQCC's approval ofthis exemption constitutedfederal approval into the SIP. This creates enforcement issues with the federally approved SIP.
We would like to meet withyou and your staffto discuss the above listed issues. Please contact us to let usknow when you are available to meet. Ifyou have further questions, please contact me at 303/312-6005 orLarry Svoboda at 303/312-6004, orhave your staffcontact Cindy Rosenberg at 303/312-6436.

cc: DougLempke, AQCC

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