Summary of interagency working comments on draft rule under EO 12866.

These comments do not necessarily represent the views of OMB and are su bject to further policy review.

1) Could EPA better describe various options that could be considered if emissions standards or other remedies are considered, including incentives or other flexible mechanisms? Consider for example that approximately 60% of Forest Service aircraft are pist on aircraft using leaded aviation fuel, including a several floatplanes. Many of these are firefighting aircraft that are critical to the protection of lives and property. A primary concern with this proposal is that many of the aircraft that we own or op erate are so old that they no longer have a manufacturer to support engine modifications to meet any new standard or conversions to unleaded fuel. Consequently, this burden would most likely fall on the current owners, and could reduce the current fleet of firefighting aircraft. Hence, the Forest Service would like the EPA and FAA to consider alternative options or additional incentives for owners and operators to replace piston aircraft with turbine powered aircraft. This could result in the same benefits of reduced lead emissions without the research and development costs of converting piston engines to unleaded fuel. 2) The exposure section should have references for all relevant statements and assertions. T he exposure section seems to use quite a few char acterization s that are not supported by referenced literature, such as the descriptions of land use near airports (ex: “Airports are often surrounded by ...recreational sport facilities...”), “airports are especially attractive to young children...” and “program s .. provide outdoor observation facilities and picnic facilities for families..”. “Personal gardens, community gardens...” etc are all characterizations that are not referenced. Perhaps there is a background document EPA could cite? 3) In the count of

school s within 1km of an airport, could EPA break out preschools, elementary schools, middle schools, high schools and colleges? This is relevant because

v ulnerable populations are typically very young (pre

- school and element ary / grammer school). 4) Could EPA pro vide references to support the statement on p 11 and Section VI “The data described in Section VI of this ANPR indicate that lead levels in ambient air on and near airports servicing piston

- fired aircraft are higher than lead levels in areas not directly i nfluenced by a lead source”. This statement seems to characterize all airports relative to all other areas, and implies we have a great deal of information about lead levels and airports and other areas. If so, that information should be discussed more f ully as it is important for the entire document. 5) We recommend that the language on p 14 in the “Background on Leaded Aviation Gasoline” section be deleted or moved, because it describes airports not Gasoline

. If the language is necessary, perhaps move it into a section about airports? (“Over 3,000 of the 20,000 airport facilities ... if this fuel was all 100LL, it would account for approximately 34,00 tons of lead emitted into the air.” ) 6) The draft ANPRM should try to focus on referenced materials and publi shed studies

. For example, “ If this fuel was all 100LL, it would account for approximately 34,00 tons of lead emitted into the air.” EPA has other estimates, such as NEI, to represent source contribution. 7) Is the endangerment finding based on current cond itions, or possible forecasted conditions? EPA mentions on p 15: “As described in III.B of this ANPR, the is a slight growth in the activity of general aviation aircraft projected to 2025.” Also, on p 59, there is a section on Projections for Future Growth. Should readers infer that an endangerment finding is based on forecasted conditions, not current conditions, or is this statement irrelevant? 8) If forecasts are relevant and retained in the text, forecast uncertainties should be clearly discussed and comment taken on forecast estimates. 9) Could EPA provide a citation on p 60 for “...prior AQCDs for Lead.” 10) What flexibility does EP A have to wa it to promulgate this ANPRM until the information is available that EPA discusses? EPA seems to be relying on only 1 study (Santa Monica Airport) to understand emissions of lead from piston

- engine aircraft, and that study is not yet complete.Summary of interagency working comments on draft rule under EO 12866.

These comments do not necessarily represent the views of OMB and are su bject to further policy review.

Furthermore, monitoring for airports have been proposed but is not yet finalized by EPA, and in fact EPA may not have finished r eviewing public comments on the monitoring reconsideration. 11) Given that there is not a monitoring network at airports now, how do monitoring studies show “...an increase in lead levels in ambient air... ” as described in the first line on p 65? Or should this r ead “higher levels at airports with piston aircraft than at airports without piston aircraft”? 12) Please provide information on the study design for the Santa Monica Study, for example why monitors were placed in certain locations, how that would help identif y lead gradient, and why only two short time periods were adopted for the study. 13) Co uld EPA explain why“..analogies to gradients in ultrafine PM are relevant” (p66). PM is both formed from precursors (unlike lead) and emitted from motor vehicles that are typically restricted to roads, whereas aircraft are not restricted to roads. 14) Is the model referenced on p70 available for public review, or is it in the docket? 15) Please confirm on p70 that EPA plans to use the study of one airport to characterize that airport, and not to generalize to other airports which may have dramatically different conditions. 16) EPA might intend to say that use of leaded avgas in piston

- fired aircraft is one of the larger sources of current emissions instead of “The continued use of lead i n avgas by piston

- engine aircraft is a significant source of lead to the environment.” On p71. 17) Does higher ambient concentration of lead result from concentrated emissions (airports) or from the fact that emissions occur at various altitudes? P71 (and ag in on p72) reads: “Piston

engine aircraft emissions of lead occur at ground level as well as at flying altitude. Consequently, lead from this source is concentrated near airports but is also deposited over a large geographic area potentially contributing to higher ambient concentrations in many communities.” 18) Could EPA define the term “fresh emissions”. Does this mean “current emissions”, or refer to something else? 19) Could EPA provide references for the background documents or analysis that supports the ch aracterization of land use around airports. (for Example: “Airports are often surrounded by a variety of land uses including recreational sport facilities, ....”o p 72

- 73) 20) Could EPA explain the statement on p74: “ The limited ambient lead monitoring data ne ar airports presented in Section IV of this ANPR suggests that for some airports this analysis will underestimate the actual number of people potentially exposed to elevated levels of ambient lead from piston

- engine powered aircraft.” 21) Could EPA provide ana lysis of Slow, Medium and Busy airports and the number of residences, schools, etc located within 1km. We suggest deciling the airports by LTO, then counting the residences, schools, and parks located with 1km of the airports in each decile. This analysi s will help explain how representative are the airports in the limited studies available and other airports in the US. 22) Could EPA provide more information on which airports are located very close to community gardens or other crop production sites. 23) The Section “Bioaccumulation of Lead” should clarify that it refers only to the environment, not to human tissue. 24) Please consider replacing the phrase “EPA is concerned about” with “EPA requests comment on”. 25) When will the Santa Monica study be available? 26) Has monit oring begun at airports listed on p95? 27) On p96, please clarify which information will be available in 2010 and which will be available in 2011 or later. 28) Please describe the limitations and uncertainties associated with the modeling EPA outlines on p98.