SITE INFORMATION AND CORRESPONDENCE_FILE 2

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Frontier Transportation, Inc* • 425 Larch Road Page 2 of 3 The EHD cannot approve the AICAP as presented for the following reasons: • The EHD has just received the first quarter 2006 monitoring report that reports the occurrence of a sheen of free product in monitoring wells MW-2 and MW-21. The 6,100 micrograms per liter(µg/1) of total petroleum hydrocarbons as gasoline (TPH-g) detected in the water sample from MW-2 is not suggestive of the close proximity of significant quantities of free phase gasoline. • There is no direct evidence of soil between 15 feet and more than 18 feet bsg being impacted with free phase gasoline, and the assumption that one-third of the pore space in the soil in this interval is occupied by free phase gasoline is purely speculative. The resulting estimate of 11,220 gallons of free phase gasoline impacting soil in this interval is therefore also speculative. Utilizing the highest detected concentration of TPH-g in soil (2,500 milligrams per kilogram, collected at 14 feet bsg in the tank pit excavation) and various grain densities and porosities, EHD calculated a TPH-g volume ranging from 266 to 300 gallons; this is assuming the same impacted soil dimensions and porosity range utilized by BEAI and that the contaminant concentration applies to the entire soil volume. EHD believes the 266 to 300 gallon estimate most likely to be an overestimation. • The EHD is not sure with whom BEAI "agrees" that soil analysis identifies almost exclusively heterogeneous clay to silty, fine-grained sand that has low permeability, rendering soil vapor extraction (SVE) of limited value in the vadose zone. The EHD does not contest the statement, but had concurred by letter dated 02 March 2006 that SVE was not likely to be an effective remedial option for this site. • The EHD had previously disapproved use of neutron logging thermalization (EHD letter of 02 March 2006), not because of site conditions, but because the EHD does not believe the technology can provide significantly useful data at this stage of site characterization. The EHD's understanding of neutron logging is that it responds to the hydrogen content of water or hydrocarbons, and cannot differentiate between the two without an independent porosity log, and BEAI has provided no information to the contrary. The EHD does not believe that NTL can be utilized to "monitor the aqueous migration of the ozone injection". As previously indicated, the EHD will reevaluate this stance on the use of NTL if provided authoritative, peer-reviewed technical publications documenting the effective use of NTL for the claimed beneficial applications. • The EHD is not certain with whom BEAI agrees that soil excavation should be attempted again in the source area. In the 02 March 2006 letter, EHD had indicated that the "potential effectiveness of partial excavation perhaps combined with a separate approach for direct groundwater remediation should be evaluated."Emphasis added. Simply stated, the EHD had not indicated that excavation should be a chosen remedial action, but that its rejection did not seem technically justified and that it should be reevaluated and compared to other potential remedial options with sound technical justifications provided for the altemative(s) selected for EHD review. • EHD believes that pumping tests could provide useful information for considering remedial alternatives for your site, however, the EHD is concerned about the proposed pumping test design. Performing a pumping test immediately outside the plume of impacted groundwater may have the unintended consequence of inducing plume migration into areas currently not impacted. Alternatively, the presence of a significant volume of free product, could complicate a pumping test in the source area. The presence