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' Environmentaltwj , Resources ]vlr.I3arlin Knoll 24 March 2070 Management Page 2 Comment 2) Ground7tuter sample results from. MW-4 at Site I u7ere: TPH-g 20,000 micrograms per liter (pg/L), toluene 135 pg/L, ethylbenzene 1,030 pg/L, and total xylene 2,160 jig/L. Response to Comment 2) This is an accurate summary of current conditions in the Tank 1 area. But it should be noted that concentrations of benzene (the primary human health risk driver of the chemicals related to petroleum hydrocarbons) are generally low to non--detectable in samples collected from this area. Benzene has never been detected in samples collected from MW-3 or MW-7. During the last monitoring event(November 2009), the highest reported detection of benzene was 5.9 pg/L (MW-1), which is only marginally above the drinking water standard of 1 µg/L. All chemical concentrations are stable or are decreasing. Comment 3) Groundwater sample results from MW-6 at Site 2 were: TPH-g 3,290 µg/L, benzene 93 µg/L, toluene 13.8 µg/L, ethylbenzene 66.4 µg/L, and total xylene 74.9 µg/L. Response to Comment 3) Similar to Comment 2, this is an accurate summary of current conditions in the Tank 2 area. It should be noted that concentrations of hydrocarbon constituents are orders of magnitude lower than those observed immediately following the tank excavation, and are generally stable or are decreasing over time. Comment 4) Groundwater contamination concentrations are too high to be acceptable for site closure. Implementation of a remedial technology for groundwater cleanup is Warranted at your site. Response to Comment 4) Heinz is not currently seeking regulatory closure for the site. Heinz has removed the primary sources of contamination (the USTs) and surrounding soils and is implementing a long-term monitored natural attenuation program for groundwater impacts. A thorough description of remediation activities, remedial technologies for soil and groundwater, and an assessment of human health risks and beneficial uses of groundwater were provided in the Underground Storage Tank Closure Report dated 7 April 2000. The highest reported concentrations in groundwater at the site are those reported for Total Petroleum Hydrocarbons in the gasoline range (TPH-G).