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the compressive strength of the grout is reduced and the risk of mechanical integrity <br />failure increases. Permit condition F.2. should be rewritten to require that the proposed <br />injection well must be constructed in compliance with the requirements of the Colorado <br />State Engineer and that written evidence of such compliance must be provided to EPA. <br />(5) EPA should include a permit condition specifying a Maximum Allowable Injection <br />Pressure of zero psig at the wellhead. Page three of EPA's Responsiveness Summary for <br />the final permit decision includes the following statement under the heading of "Changes <br />to the Permit": <br />The Final Permit establishes a Maximum Allowable Injection Pressure of zero at <br />the well head. This requirement is included as a response to concerns that <br />injection under pressure could result in A2 sandstone groundwater moving across <br />a confinement zone into another underground source of drinking water. <br />On page eight, EPA says "the groundwater will not be injected under pressure." An EPA <br />response on page 13 also addresses this issue: <br />The Final Class V Permit includes a requirement that the injection will be <br />conducted under zero injection pressure at the wellhead. Because the proposed <br />injection activities will be conducted at zero pressure, even if historic boreholes <br />have compromised the integrity of the confinement zone, the injection pressure <br />will not induce the migration of injectate into the Laramie Formation or the <br />underlying WE sandstone unit that is not already occurring under exisiting <br />conditions. <br />Page 21 includes a similar response on Maximum Allowable Injection Pressure: