EPA/ESD/R08-98/176 1998 EPA Superfund Explanation of Significant Differences: LOWRY LANDFILL EPA ID: COD980499248 OU 00 AURORA, CO 10/24/1997 EPA 541-R98-176 <IMG SRC 981760> <IMG SRC 98176A> February 12, 1998 Subject: Responsiveness Summary for the Second Explanation of Significant Differences, Lowry Landfill Superfund Site Dear Sir/Madam: Please be advised that there is an error within Attachment E (Technical Evaluation of Proposed Ground-Water Treatment and Disposal Alternatives) of the above-referenced document. The mistake was recently brought to my attention by the Citizens for Lowry Landfill Environmental Action Now (CLLEAN). The evaluation table, which summarizes the rankings of the two cleanup alternatives, failed to include numerical values for State Acceptance and Community Acceptance. This was an unintentional mistake and I take complete responsibility for the mixup. Enclosed is a copy of the table as it should have appeared in Attachment E. Copies of this errata sheet are being mailed to all recipients of the Responsiveness Summary. The corrected ratings for State Acceptance and Community Acceptance are now consistent with the existing text on page 8 of Attachment E of the Responsiveness Summary. I believe the existing text adequately reflects the community's stated opposition to Alternative 1 and preference for Modified Alternative 2B. If you know of anyone who may have previously received a copy of the Responsiveness Summary but did not receive the enclosed, corrected table, please either pass on a copy to them or have them contact me. If you have any additional questions, I can be reached at 1-800-227-8917 (extension 6724) or 303/312-6724. <IMG SRC 98176B> Enclosure EPA Assessment Criterion Alternative 1 Modified Alternative 2B 1. Overall Protection of Hwnan Health & the Environment 5 5 2. Compliance with ARARs 5 5 3. Long-Term Effectiveness and Permanence 3 2 4. Reduction of TMV Through Treatment 4 3 S. Short-Term Effectiveness 3 3 6. Implementability 5 3 7. Cost 4 2 8. State Acceptance 5 4 9. Community Acceptance 1 5 Total Score 35 32 Note: 5 = completely achieves the objectives of the criterion; 1 = minimally achieves the objectives of the criterion Responsiveness Summary for the Second Explanation of Significant Differences Lowry Landfill Superfund Site ARCS Contract No. 68-W6-0036 EPA Work Assignment No. 016-ROBF-0808 CH2M HILL Master Project No. 139814 DCN 97-456 Volume I of II Prepared for U.S. Environmental Protection Agency Prepared by CH2M HILL October 1997 Preface (How to Find Your Letter) More than 400 letters with comments were submitted to the United States Environmental Protection Agency (EPA) during the public comment period on the Lowry Landfill Superfund Site Second Explanation of Significant Differences. This Responsiveness Summary document provides responses to all of the comments and questions received in those letters and other communications during that period. This preface explains how to find a particular letter within this two-volume document. This document is composed of the following, two volumes: Volume I • Preface • Executive Summary • Comment Letters Index • Acronyms and Abbreviations • Responses • References • Glossary • Attachments Volume II • Preface • Comment Letters Index • Copies of the original comment letters To find a particular letter in this document, go to the Comment Letters Index that follows the Executive Summary in Volume I and this Preface in Volume II and search for the last name of the person who signed the letter. The Comment Letters Index is arranged alphabetically by the last name of the persons who signed the letters. In some cases, signatures on some of the letters were not legible. Because other copies of the form letters were available, these illegible signatures. are not included in the Comment Letters Index, but copies of the form letters with the illegible signatures are included in Volume II. The Comment Letters Index is divided into three columns. The first column is arranged alphabetically by last name. The second column provides the page number in Volumn II where a copy of the original letter the person signed can be found. The third column provides the page number in Volume I where the responses to the letter(s) the person signed can be found. In some cases, the same person sent in more than one letter. In these instances, there are multiple page numbers listed in the second and third columns. A number of questions repeated frequent themes. The Executive Summary presents general responses to these frequently asked questions. Some of the responses in the document refer the reader to specific sections of the Executive Summary so that the response is complete. When a response says (see Executive Summary-Sludge/ solids), this means the reader is referred to the section in the Executive Summary with the heading "Sludge/Biosolids." Additionally, the Executive Summary contains an overview of the Lowry Landfill Superfund Site history and a description of the Publicly Owned Treatment Works option. Upon receipt of all of the comments at the close of the public comment period, EPA and the Colorado Department of Public Health and Environment (CDPHE) carefully reviewed and evaluated each comment. Based on this review and thoughtful consideration, EPA and CDPHE developed a response to each comment. These responses are presented in Volume I. Executive Summary Responsiveness Summary for the Lowry Landfill Superfund Site Second Explanation of Significant Differences October 1997 Introduction The purpose of this executive summary is to provide: In accordance with the requirements, of the Comprehensive Environmental Response, 1. An overview of the site history and status; Compensation, and Liability Act 1 of 1980, as amended (CERCLA), 42 U.S.C. 9601,et seq., 2. A summary of the approved changes in the Pollution Contingency Plan (NCP), 40 C.F.R. Second ESD; and Part 300, et seq., this responsiveness summary presents the response of the United States 3. Responses to the issues raised most Environmental Protection Agency (EPA) and the frequently in the comments. Colorado Department of public Health and Environment (CDPHE) to Public Health and Each comment is responded to in detail within received on the Second Explanation of the body of the Responsiveness Summary. To Significant Differences (ESD), dated March conserve paper, space, and money, copies of the 1997. The comments were received during the complete Responsiveness Summary are available public comment period that extended from March at the locations listed on the last page of this 24 through June 30, 1997. Community members executive summary. submitted comments on the proposed changes to the Record of Decision (ROD) for the Lowry Landfill Superfund Site (Lowry Site or Site) in Arapahoe County, Colorado. More than 400 written comments were received on the ESD in addition to the comments received during the public meeting held on April 2, 1997. All of these comments have been responded to in the Responsiveness Summary, which consists of this Executive Summary, Volume I, which contains the responses, and Volume II, which contains copies of the original letters. The purpose of this executive summary is to provide an overview of the site history and status, a summary of the proposed and now approved changes in the Second ESD, and address the issues that were most frequently raised in the comments. More detail on each of the topics raised in this Executive Summary can be found in the responses to comments in Volume I. Each comment is responded to in detail in the body of the complete Responsiveness Summary. 1 Bolded terms are defined in the Glossary. Contents Summary of Site History and Contamination Problems................................page 2 Summary and Status of Selected Sitewide Remedy....................................page 3 Description of the Second Explanation of Significant Differences (ESD)............page 4 Public Comments Overview..........................................................page 6 <IMG SCR 98176C> Summary of Site History and Contamination Problems The Lowry Site is located northeast of the intersection of Quincy Avenue and Gun Club Road, approximately 15 miles east of the City and County of Denver (Denver), Colorado. In the late 1930s, Denver bought 60,000 acres of land (the Lowry Site comprises about 480 acres of this land) to attract an Army Air Corps Technical School to Denver. In 1939, the Denver City Council transferred the land to the Federal government. From about 1940 to 1962, the United States Air Force used the land as a bombing range. In 1964, the United States transferred portions of the bombing range back to Denver. From 1966 until 1980, Denver operated a landfill at Section 6 on the Lowry Site, taking in liquid and solid household and industrial wastes. These wastes included hazardous substances, such as volatile organic compounds and inorganics. Organic compounds contain the element carbon. Examples of organic compounds include petroleum products, solvents, and pesticides. Volatile organic compounds are organic compounds that tend to evaporate easily. Inorganic compounds include metals (such as arsenic and selenium), chlorides, and sulfates. Over 120 million gallons of liquid waste were disposed of at the Lowry Site, primarily using a practice known as "co-disposal." Some 75 unlined waste pits or trenches were dug to hold the mixed household and industrial wastes. In the southern half of the Lowry Site, the pits were filled with liquid wastes and then covered with 25 to 60 feet of household waste. The waste pits were about 15 to 30 feet deep, about 100 to 1,100 feet long, about 50 to 150 feet wide. Over time, the liquids seeped out of the pits and mixed with the household waste and ground water. In the central part of the Lowry Site, the pits were filled with liquid wastes and household waste, then covered with 2 to 5 feet of soil and used tires. Over time, these liquid wastes seeped into the ground water and into Unnamed Creek.