Responsiveness Summary Report November 16, 2018 Public Meeting, Agreed Order, and Public Participation Plan For Reserve Silica Reclamation Site 26000 Black Diamond-Ravensdale Road Ravensdale, WA 98051 Prepared by Washington Department of Ecology Northwest Regional Office 3190 160th Avenue SE Bellevue, WA 98008-5452 January 29, 2020 Publication and Contact Information This plan is available on the Department of Ecology’s website at: https://fortress.wa.gov/ecy/gsp/Sitepage.aspx?csid=4728 For more information contact: Northwest Regional Office 3190 160th Ave SE Bellevue WA 98008 425-649-7052 Washington State Department of Ecology — www.ecology.wa.gov • Headquarters, Olympia 360-407-6000 • Northwest Regional Office, Bellevue 425-649-7000 • Southwest Regional Office, Olympia 360-407-6300 • Central Regional Office, Union Gap 509-575-2490 • Eastern Regional Office, Spokane 509-329-3400 To request ADA accommodation including materials in a format for the visually impaired, call Ecology at 425-649-7000 or visit https://ecology.wa.gov/accessibility. People with impaired hearing may call Washington Relay Service at 711. People with speech disability may call TTY at 877-833-6341. Table of Contents Introduction ..................................................................................................................................... 4 Status Update on Site Separation .................................................................................................... 4 Public Participation Comments....................................................................................................... 6 Liability Comment .......................................................................................................................... 9 Site Definition Comments............................................................................................................... 9 Groundwater Hydrology Comments ............................................................................................. 17 Chemicals of Potential Concern Comments ................................................................................. 20 Seismic Comment ......................................................................................................................... 23 Treatment System Comment......................................................................................................... 24 List of Attachments ....................................................................................................................... 25 Attachment 1 ................................................................................................................................. 26 Attachment 2 ................................................................................................................................. 27 Attachment 3 ................................................................................................................................. 28 Attachment 4 ................................................................................................................................. 29 Attachment 5 ................................................................................................................................. 30 Attachment 6 ................................................................................................................................. 31 Attachment 7 ................................................................................................................................. 32 Attachment 8 ................................................................................................................................. 33 Attachment 9 ................................................................................................................................. 34 Introduction The Department of Ecology (Ecology) and potentially liable persons (PLPs)1 Reserve Silica Corporation (Reserve Silica) and Holcim (US) Inc. (Holcim) held a public meeting on November 16, 2018, to discuss the status and planned remediation approach for the Reserve Silica Corporation site. Ecology held a 30-day public comment period (November 5th through December 7th 2018) on the draft Agreed Order (AO) and Public Participation Plan (PPP). This Responsiveness Summary addresses the draft Agreed Order; reference the draft AO (Attachment 1) when reviewing the comments below. The draft Agreed Order stipulated that the PLPs prepare a Remedial Investigation (RI) and Feasibility Study (FS) for the site, in accordance with WAC 173-340-350 and Ecology Publication Numbers 16-09-006 (Remedial Investigation Checklist) and 16-09-007 (Feasibility Study Checklist). Ecology requests the RI and FS be prepared as separate documents. The RI should be a comprehensive document for the site that describes the history, previous environmental investigations, previous and ongoing cleanup actions, additional characterization, and Conceptual Site Model for the site. The RI should include sufficient detail to develop and evaluate cleanup alternatives in the subsequent FS report. The approved RI will define the site boundary, the chemicals of concern (COCs), and the cleanup standards for the Site. The PLPs are encouraged to consider the public comments during the development of the Reserve Silica Reclamation site RI Work Plan (RI Work Plan) and the RI report. Ecology categorized the public comments as public participation, site definition, groundwater hydrology, chemicals of potential concern (COPCs), seismic concerns, and treatment system comments. Ecology’s expectations and response to these comments are described in the following sections. Status Update on Site Separation Reserve Silica and Holcim entered into an Agreed Order with Ecology on December 16, 2019 for the investigation and cleanup of contamination on the Reserve Silica Reclamation site in accordance with Model Toxics Control Act (MTCA). The Reserve Silica Corporation site was renamed as the Reserve Silica Reclamation site (Facility/Site ID 2041, Cleanup Site ID 4728, website: https://fortress.wa.gov/ecy/gsp/Sitepage.aspx?csid=4728 ) on November 18, 2019. The Reserve Silica Plant site (Facility/Site ID 19532, Cleanup Site ID 15125, website: https://fortress.wa.gov/ecy/gsp/Sitepage.aspx?csid=19532 ) was identified as a new site on November 18, 2019 and listed on the Confirmed and Suspected Contaminated Sites List on December 24, 2019. Reserve Silica plans to independently investigate and cleanup the Reserve Silica Plant site in accordance with MTCA. Discussion of the site separation are discussed below. 1 On March 5, 2018, Ecology determined that BNSF Railway is also a PLP for the site, but BNSF Railway has declined to participate in the implementation of this Agreed Order. 4 The current site configuration for the Reserve Silica Plant Site and Reserve Silica Reclamation Site is below. Silica Cleanup Site Overview Plant Site -- 1 1 Reclamation Site 1,000 Feet .. - ,. Preliminary Boundary DEPARTMENT OF ~- -_ -~ Property Boundary ECOLOGY State of Washington 5 Public Participation Comments Ecology intends to allow public review of the RI Work Plan, and hold formal public comment periods for the RI and the FS. The Draft Cleanup Action Plan (DCAP) will also undergo a public comment period. However, the scope of work under this Agreed Order covers the RI/FS activities up to and including submittal of the Agency Review Preliminary DCAP to Ecology. The DCAP public comment period will occur after the work of this Agreed Order is complete. Ecology will receive quarterly progress reports and will update the public by providing periodic brief oral presentations at regularly scheduled Greater Maple Valley Unincorporated Area Council (GMVUAC) meetings or upon request. Public comment 1: GMVUAC Comment 3 (Attachment 5) The Draft Agreed Order and Public Participation Plan should be amended to include a required public comment period regarding and relating to the forthcoming Work Plan, so that members of the Public have an opportunity to review and comment on it before it is implemented as part of the RI/Feasibility Study. To ensure the Public Participation Plan includes public notice and an opportunity for the public to submit comments to Ecology on the draft Work Plan before it is finalized, we suggest the following modified excerpt from Ecology’s November 30, 2018, e-mail be included in the final Public Participation Plan: "The proposed RI Work Plan will be made available to the public for review and comment before it is finalized and implemented. Because Work Plans are generally not subject to formal public review and comment, in addition to posting notice on its Document Repository for Reserve Silica Corporation website the Department will send a Notice of Draft Work Plan Availability to only those individuals and entities who have submitted written comments on the Draft Agreed Order and/or Public Participation Plan. The Department will consider all public comments received and appropriately include such comments in the final Work Plan." We wish to continue an open dialogue with Ecology officials on Reserve Silica Site cleanup. Thank you in advance for your careful consideration of our comments. Ecology response to Public comment 1: Ecology revised the Public Participation Plan by adding the following paragraphs under the heading “Public comment periods”: “Ecology will send a notice of availability of the Remedial Investigation Work Plan to those individuals who submitted