August 26, 2014



Members In Attendance:



Richard Alper


Lucinda Smith, City of Fort Collins

Cassie Archuleta


David Lemesany, Martin Marietta Materials

Chase Eckerdt


Ken Ball, Martin Marietta Materials

Derek Esposito


Jerimy Runner, Martin Marietta Materials

Michael Jones


David Stewart, Stewart Environmental

Evelyn King



Ryan McShane



Joseph Wilson


Lew Gaiter






Staff :



Doug Ryan


Introduction of Members and Guests:

Those in attendance introduced themselves.


Citizen Comments:

No citizen comments were presented.


Discussion Items:

Martin Marietta Materials draft Air Emissions Permit.

The Advisory Board conducted its review of the Colorado draft air emissions permit number 13LR2446 for the Martin Marietta Materials (MMM) asphalt plant located at 1800 North Taft Hill Road outside Fort Collins.  Review by the ESAB was requested by the Board of County Commissioners to assist the Commissioners should they choose to file comments on the draft during the public comment period ending on September 3, 2014. 


A primary resource used in their review was the technical analysis of the draft permit prepared by Air Resource Specialists (ARS), Inc., dated August 2014.  The technical analysis was prepared for Larimer County and the City of Fort Collins. 


Other supporting materials for this specific meeting include an email message from Karen Hare, representing comments from Citizens Against Asphalt Toxins (CAAT), and the written recommendations to the City Council from the Fort Collins Air Quality Advisory Board – both dated August 25, 2014. 


At the conclusion of the discussion, Evelyn King moved and Ryan McShane seconded a motion to authorize a memo to the County Commissioners recommending approval of the air emissions permit subject to a series of comments and conditions.  The ESAB memo, which includes the comments and conditions discussed by the Advisory Board, is included as an attachment to these minutes. 


Stewardship Awards.

The nomination period for the 2014 Environmental Stewardship Awards ends on September 9th.  Advisory Board members Michael Jones, Derek Esposito, Cassie Archuleta and Chase Eckerdt volunteered to serve on the awards committee that will perform the initial review and report back to the full ESAB.  Nominations can be made online at


Approval of Previous Minutes:

Minutes from the July 8 and August 18 meetings were approved as presented.


ESAB Issue Index:

Doug Ryan will update the Issue Index related to the topics discussed at the meeting.


September 9 Meeting Agenda:

Solid waste update, zoonosis update, ESAB Issue Index review



The meeting ended at 9:05 PM




Post Office Box 1190

Fort Collins, Colorado  80522-1190


To:                   Larimer County Board of Commissioners  


From:               Michael Lee Jones, Chair   


Date:               August 28, 2014


Subject:           Martin Marietta Materials Construction Draft Permit – Review and Recommendations


The Larimer County Environmental and Science Advisory Board (ESAB) has completed its review of the Colorado draft air emissions permit number 13LR2446 for the Martin Marietta Materials (MMM) asphalt plant located at 1800 North Taft Hill Road outside Fort Collins.  Review by the

ESAB was requested by the Board of County Commissioners to assist the Commissioners should they choose to file comments on the draft during the public comment period ending on September 3, 2014. This memo provides our conclusions and recommendations.


A primary resource used in our review was the technical analysis of the draft permit prepared by Air Resource Specialists (ARS), Inc., dated August 2014.  The technical analysis was prepared for the Larimer County Department of Health and Environment and the City of Fort Collins Environmental Services Department.  The analysis was helpful in three respects: first, it verified that the dispersion modeling performed by the Air Pollution Control Division (APCD) was done correctly and followed applicable regulatory guidelines; second, the analysis went beyond the modeling performed by APCD to provide information on hazardous air pollutants (HAPs) of concern to residents in the area of the source; and third, the analysis provided a number of recommended conditions that, if included in the final APCD air permit, will provide valuable assurances to the public without unreasonably burdening the operations of the facility.   The ARS report relied on published data from the USEPA and the State of California Reference Exposure Levels regarding industry-specific emissions levels and potential health effects.  Our review did not include a separate analysis of those primary sources.


The emissions inventory and air dispersion modeling are important tools for predicting the potential impact to the surrounding community from airborne pollutants.  The ESAB found that a number of conservative assumptions were incorporated into these tools that serve to purposely over-estimate the results such that they produce a worst-case scenario of modeled emissions.  Our conclusion from the State’s modeling and the additional research performed by ARS concerning HAP is that the modeled emissions are not expected to exceed published health-based standards or recommended exposure levels at the public interface.


Following our review, the ESAB adopted a unanimous motion to recommend approval of the draft air emissions permit subject to the following comments or conditions:


a)   The emissions inventory for the draft permit includes the emissions from the asphalt plant, but not from the related aggregate mining and processing operations conducted by MMM on the west side of Taft Hill Road.   Under the Clean Air Act, we believe that emissions from those operations should be included as part of the air emissions sources considered for this permit.  ARS suggests that it is unlikely that the added emissions from the adjoining operations will alter the minor/major source classification of the asphalt plant, but a complete and accurate analysis requires that these emissions also be considered when determining the total emissions from the source. 

b)   The draft permit requires submittal of an Operations and Maintenance (O&M) Plan to the APCD for approval.  It is important that the O&M Plan receive adequate review and oversight both in its initial development and as it may be updated in the future.  Due to the technical nature of these plans, the need for periodic revisions, and in light of the other conditions being recommended for inclusion in the air permit, the ESAB is not recommending that a public review process be conducted.  We do, however, wish to emphasize the importance of a thorough technical review by the APCD and the ultimate release and public availability of the O&M Plan. 

c)   Two additional emission control methods currently in use at the asphalt plant should be made mandatory in the permit under Conditions 7, 10, and 13.  Those controls are 1) the capture of volatile organic compound (VOC) emissions from the finished asphalt product silo and routing them back to the asphalt burner, and 2) the vapor condenser equipment installed on the liquid asphalt tanks.  As noted in the technical report prepared by ARS, these controls are necessary to minimize asphalt emissions and odors that have been the subject of community complaints.  By virtue of their existing installation and use at the facility, these controls constitute Reasonably Available Control Technology (RACT) required for ozone non-attainment areas. 

d)   The emission rate value for carbon monoxide (CO) used in the draft permit is higher than the reference value listed in the USEPA AP-42 standard publication for natural gas or LPG-fired drum mix asphalt plants.  The Fort Collins area is classified as an attainment maintenance area for CO.  Permits issued in other jurisdictions have set the CO permit levels using the AP-42 emissions value.  While it is recognized that use of a higher emission rate is a conservative assumption for the dispersion modeling, the use of the lower AP-42 emission rate could reasonably be considered as RACT in order to limit CO emissions.  The ESAB recommends that the standard AP-42 CO emission rate value of 0.13 pounds/ton of asphalt be specified for this permit or, alternatively, APCD should clearly state the technical basis for its decision to use a higher emission rate in the permit under Condition 13.

e)   The draft permit requires opacity testing in Condition 15.  Because the plant is approved to operate on both natural gas and LPG as fuel, the opacity testing should be conducted for the plant on both approved fuels.

f)   Condition 16 requires a stack test within 180 days of permit issuance.  The ESAB recommends that the stack test be conducted for both natural gas and LPG fuel cycles. 

g)   The stack test referenced in Condition 16 does not specify if the particulate testing is required to include condensable particulate matter (CPM), a subcategory of PM2.5.  The hot exhaust from the baghouse emission stack suggests that CPM emissions may be present.  The ESAB recommends that CPM emissions be included in the particulate matter stack test or, alternatively, that the APCD clearly state why they are not required to be measured for this permit.

h)   The stack test referenced in Condition 16 does not require testing for HAPs.  These pollutants represent a significant concern for the community.  Air dispersion modeling extended to HAPs by ARS in their technical review indicates that their concentrations at community locations should be well below recommended health-based thresholds.  In order to verify, or “ground truth”, those results, the ESAB recommends that the APCD create an appropriate list of hazardous emissions to be included in the stack tests.  Those measured emissions should then be compared to the emissions inventory referenced in Note 4 on the draft permit.

i)   Three hazardous pollutants associated with asphalt plants, xylene, hexane and polycyclic aromatic hydrocarbons (PAH), are relevant as they are listed with AP-42 emissions factors and should be added to the draft permit inventory.  Also, the emission factor listed for toluene in the draft permit appears to be from #2 fuel oil rather than natural gas; this should be corrected. 


j)   The ESAB understands that the requirement for a stack test is a one-time requirement for this permit issuance.  In terms of maintaining consistency with other permit decisions by the APCD, the ESAB recommends that the Division consider whether a recurring stack test should be required based on APCD actions in similar situations. 

k)   A relevant concern voiced by area citizens relates to the level of air emissions expected when differing amounts of recycled asphalt are used in the process.  The ESAB recommends that the draft permit include a discussion of this issue with reliance on relevant literature and experience in facilities using increased levels of recycled asphalt.

l)   Condition 8 in the draft permit limits the annual production of asphalt.  The ESAB recommends that the hourly production rate of 400 tons/hour also be specified as a limit, as that production rate was used to estimate the maximum emission rates for the facility. 

m)   Odor control remains an important issue for the community and is referenced in Condition 10.  The ESAB encourages MMM to continue its efforts to meet community expectations through the implementation of appropriate odor control practices. 



The ESAB appreciates the opportunity to advise the Commissioners on this important issue.  The ESAB also wishes to express appreciation to the Commissioners for allowing expenditure for the services provided by ARS without which this detailed analysis would not have been possible. Please contact me or Doug Ryan if you would like to discuss any of these comments in greater detail.