MNA Frequently Asked Question (FAQ) 3. What is the purpose of the Monitored Natural Attenuation Directive?
OSWER Directive 9200.4-17P clarifies EPA’s policy with regard to the use of monitored natural attenuation for the remediation of contaminated soil and groundwater at sites regulated under all programs administered by EPA’s Office of Solid Waste and Emergency Response (OSWER), including Superfund, RCRA Corrective Action, and Underground Storage Tanks. The Directive is intended to promote consistency in how monitored natural attenuation remedies are proposed, evaluated, and approved. As a policy document, it does not provide technical guidance on evaluating Monitored Natural Attenuation remedies. The April 21, 1999 version of the Directive was issued as “Final” and should be used immediately. It provides guidance to EPA staff, to the public, and to the regulated community on how EPA intends to exercise its discretion in implementing national policy on the use of Monitored Natural Attenuation (MNA). The document does not, however, substitute for EPA’s statutes or regulations, nor is it a
