US EPA RECORDS CENTER REGION 5 vreostii. s o UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 51 illIV w o o REGION 5 -• ,.,. 77 WEST JACKSON BOULEVARD CHICAGO, IL 60604-3590 41- PRo-res' 936358

SEP 2 6 2017

MEMORANDUM REPLY TO THE ATTENTION OF:

SUBJECT: ACTION MEMORANDUM - Request for a Time-Critical Removal Action at the Grand Traverse Overall Supply Site (Residential Investigation), Greilickville, Leelanau County, Michigan, 49684 (EPA Site ID # 053G)

FROM: Ralph Dollhopf, OSC Emergency Response Branch 1

THRU: Jason H. El-Zein, Chief Emergency Response Branch 1

TO: Margaret Guerriero, Acting Director Superfund Division

I. PURPOSE

The purpose of this Action Memorandum is to seek approval of an additional expenditure for a time critical removal action to mitigate threats to public health and the environment at the Grand Traverse Overall Supply (GTOS) Site, (the Site) in Greilickville, Leelanau County, Michigan, 49684. On July 27, 2017, the On-Scene Coordinator (OSC) authorized emergency expenditures of up to $25,000. This was increased to $75,000 on August 11, 2017 and later to $250,000 on August 16, 2017 by the Chief of the Emergency Response Branch 1, to mitigate threats to public health and welfare posed by the presence of potentially explosive concentrations of methane in soils adjacent to residential structures located near the Site. Methane has migrated from these soils to into confined crawl spaces of some of the residential structures. These structures are located within the plumes of contaminated groundwater and contaminated soil vapor which EPA has previously deteimined are the result of improper disposal of chlorinated, industrial cleaning chemicals at the Site. In addition, investigation to date indicates that that the residential structures are located near buried, decomposing sawdust that is likely generating high levels of methane. This Action Memorandum seeks your approval to expend up to $607,195, in order to continue to mitigate threats to public health and welfare by the presence of potentially explosive levels of methane in residential soils which are accumulating within residential structures, and in addition to mitigate threats to public health and welfare by the presence of in residential soils.

Methane (CH4) is a colorless, odorless, tasteless gas and can be referred to as natural gas, light carburetted hydrocarbon, firedamp, and marsh gas. High methane concentrations can cause oxygen-deficient atmospheres, flammable situations, or explosive environments. When methane enters the atmosphere as a point source, it can be readily ignited if the concentration exceeds 5 percent. Atmospheric methane can ignite at concentrations between 5

Recycled/Recyclable • Printed with Vegetable Oil Based Inks on 100% Recycled Paper (100% Post-Consumer) and 15 percent at Standard Temperature and Pressure (STP). Higher levels can quickly dilute to flammable levels. In either case, if methane is allowed to accumulate in an enclosed area, such as a residential crawl space, an explosive environment may develop. An explosive environment exists when a mixture of gases can self-propagate a flame throughout the mixture, independent of, and away from, the source of ignition. An ignition source can be an electrical outlet, pilot light, well pump, or match.

The subterranean migration of methane can present a hazard at the ground surface, primarily in structures (buildings). Potential sources include: decaying organic matter, swamps, abandoned/improperly constructed gas wells, natural seeps, leaking pipes, landfills, and abandoned or active coal mines. Entry into a structure can occur through cracks in the floor, along buried utilities, or as a dissolved component of water. When allowed to accumulate in a structure, an explosion may result.

Hydrogen sulfide is also generated by anaerobic of organic material. It is flammable and highly toxic. It has also been recently detected in soils within the residential area and at the same locations where methane levels are high. To date, hydrogen sulfide has not been detected at elevated levels except in subsurface soils.

This response action will be conducted in accordance with Section 104(a)(1) of the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), 42 U.S.C. § 9604(a)(1), and 40 C.F.R. § 300.415 of the National Oil and Hazardous Substances Pollution Contingency Plan (NCP) to abate or eliminate the immediate threats posed to public health and/or the environment.

The uncontrolled conditions posed by methane and hydrogen sulfide in soils immediately adjacent to residential structures at the Site require that this removal action be classified as both emergency and time-critical. The OSC anticipates that response actions will take up to 270 days to complete.

II. SITE CONDITIONS AND BACKGROUND EPA ID: MID017418559 Site Address: 10753 East Cherry Bend Road in Greilickville, Elmwood Township, Leelanau County, Michigan, 49684 Category: Emergency and Time-Critical Removal Actions

1. Physical Location

The Site is located at 10753 East Cherry Bend Road in Greilickville, Elmwood Township, Leelanau County, Michigan (see Figures 1 and 2). An industrial dry cleaner, now vacated, previously occupied the property. The facility was originally owned and operated by GTOS from 1950 through 1987. In 1996, the property was purchased by Iceless Company, which leased the property to Unitog Rental Services, Inc., and later to Cintas Corporation, which most recently engaged in non-solvent based cleaning operations at the site until May 2005. The on-site building remained in place (but was not occupied or operated) until December 2007, when it was demolished in preparation for removal activities. The property is situated directly west of the fornier Norris Elementary School, located at the corner of East Cherry Bend Road and Highway M-22. Cedar Lake is located about 400 feet northwest of the site. Cedar Creek, the outlet of Cedar Lake, flows easterly along the northern property line of the site to Grand Traverse Bay, which is about 0.25 mile east of the site. A church is located southeast of property at the corner of M-22 and East Cherry Bend Road. Former seepage lagoons historically used for discharge of industrial wastewater were located along the northern boundary of the property between the former building and Cedar Creek. In addition to the seepage lagoons, a dry well was also reportedly used for discharging wastewater.

2. Site Background

Since 1978, the Site has been the subject of ongoing environmental investigation and regulatory enforcement activity. In April and May 1978, the Michigan Department of Public Health detected PCE, TCE, and 1,2-DCE in samples from the Norris Elementary School drinking water well and private residential drinking water wells near the site. In October of the same year, the Michigan Department of Natural Resources (MDNR) Water Quality Division performed a biological evaluation of Cedar Creek. MDNR concluded that the stream quality and biological community were degraded as a result of discharges from the Site. Remedial action was taken by GTOS under MDNR supervision from 1978 to 1980.

The Site was included on the National Priorities List (NPL) in September 1983 because of groundwater contamination. From 1995 to 1996, Conestoga-Rovers and Associates completed Phase I and Phase II environmental site assessments (ESA) and a baseline environmental assessment (BEA) for a prospective operator of the GTOS property. Samples collected from beneath the GTOS building slab identified elevated concentrations of chlorinated VOCs in soil and groundwater, indicating a potential additional contaminant source. From 2001 through 2003, Earth Tech, Inc. (Earth Tech), performed an additional groundwater investigation downgradient of the GTOS building source area for the MDEQ Remediation and Redevelopment Division (RRD) Superfund Section. As part of the effort, temporary monitoring wells were installed along the groundwater flow path toward Grand Traverse Bay. These temporary wells detected PCE and TCE. The highest levels detected were around 16,000 micrograms per liter (µg/L).

EPA collected soil and groundwater samples from under the Site's building floor in 2005. Groundwater samples collected from under the building contained primarily PCE at concentrations as high as 1,100 1.1g/L and TCE at concentrations as high as 14 ug/L.

EPA's monitoring well installation and sampling program was completed in 2005. The findings from this sampling effort indicated a groundwater plume contaminated with concentrations of VOCs that exceeded the MDEQ Part 201 Generic Cleanup Criteria levels, extending from under the on-site building to Grand Traverse Bay.

From 2006 through 2008, Earth Tech conducted periodic groundwater and surface water monitoring on behalf of MDEQ. Earth Tech conducted groundwater and surface water monitoring in October 2006, May and November 2007, and February and May 2008, with its last monitoring event conducted in May 2008. Analytical results from Earth Tech's groundwater and surface water monitoring suggest that the groundwater plume continued to move toward Grand Traverse Bay.

On behalf of EPA, SulTRAC began quarterly groundwater and surface water monitoring in June 2009. In addition, in December 2011, SulTRAC installed seven additional wells at and around the GTOS site that would be sampled during subsequent groundwater monitoring events. Two wells were installed on the GTOS property; one well was installed on the school property; one well was installed on the West Bay Covenant Church property; and three wells were installed on the Harbor West Condominiums property. All seven wells were first sampled during the December 2011 quarterly sampling event.

3. Current GTOS Site Characteristics

In November 2012, SulTRAC's subcontractor began installation of a groundwater pump and treat system at the GTOS site. Five extraction wells, eight remedial action (RA) monitoring wells, and eight piezometers were installed as part of the pump and treat system. Four of the extraction wells are located on the east side of Norris Elementary School, and one extraction well is located near the West Bay Covenant Church. Starting in the June 2013 quarter, these RA monitoring wells, piezometers, and extraction wells have been gauged for static water levels. In addition, RA monitoring wells have been sampled for analysis of VOCs. The pump and treat system began operating in November 2013.

Between April and July 2015, SulTRAC conducted an RA at the GTOS site to treat groundwater and soil contamination at the source. In situ treatment included enhanced reductive dechlorination by injecting zero-valent iron and organic carbon substrates, and bioaugmentation. An additional 10 RA monitoring wells were installed at the site to monitor groundwater treatment perfoimance. Since the June 2015 quarterly sampling event, these RA monitoring wells have been gauged for static water levels and have been sampled for VOCs. These RA monitoring wells have also been sampled for additional parameters specific to evaluate the perfoli lance of in situ groundwater treatment.

4. EPA Remedial Response Branch (RRB) Request for Emergency Response Branch (ERB) Assistance

Methane is known to be generated as a byproduct of the groundwater treatment process described above. Methane was first identified in the treatment area associated with the GTOS Superfund Site (west of the foimer Norris Elementary School) in late 20151.

1 EPA operates three extraction wells located between the treatment area and the Harbor West Marina Village residential area where dangerous levels of methane have been found. These extraction wells are used to pump contaminated groundwater to a treatment area where the contamination is removed, and the cleaned groundwater is discharged to a surface water body (Cedar Creek). These extraction wells are believed to be capable of preventing methane or substances causing the methane generation from migrating from the treatment area into the residential area where dangerous levels of methane were found. However, for a six-week period of time in late 2015 and early 2016, these wells were known to have been non-operational because of "biofouling" resulting from enhanced methanogenic biodegradation of site groundwater (see Administrative Record (AR) document#7 in attached AR Index In 2015 EPA began monitoring soil gas in areas beyond the treatment area (downgradient) to evaluate whether the methane was migrating to those areas. In the Spring of 2016, EPA took a soil gas sample in a residential area approximately 900 feet from the treatment area that had a dangerously high methane concentration. Because of its distance from the treatment area and the fact that no other soil gas samples taken in this residential area had methane concentrations anywhere near this level, this was suspected to have originated from a supplied natural gas leak. The utility company supplying the area's natural gas was contacted, conducted an investigation, and was unable to identify a gas leak and did not detect any methane at dangerous levels.

EPA conducted an additional round of sampling in late February 2017, and when analytical results returned in March 2017 showing dangerous methane levels at this same isolated location, EPA's RRB requested support from the ERB of Region 5.2

5. ERB Emergency Site Assessment (April-July 2017)

Emergency site assessment activities conducted by ERB since March 2017 have identified the following:

• high levels of methane (up to 70% by volume) are present in shallow surface soils adjacent to two of six residential condominium structures within the Harbor West Marina Village Condominiums (see Figure 4); 3 • Hydrogen sulfide has also been detected in shallow surface soils within the areas where high levels of methane have been detected (see Figure 5). Hydrogen sulfide is a flammable and extremely toxic gas which, like methane can also generated by decomposition of organic substances;4 • one structure contains four condominium units and the other contains five; • the four other structures which contain 19 additional individual units do not appear to be affected; • sawdust buried beneath a shallow groundwater table underlays at least one of the two affected buildings; • the condominiums are built upon the foimer location of a 19th century sawmill which burned down in 1907 (see Figure 6); 5 • methane is migrating into the crawl spaces of two units in one of the two affected buildings; there are indications that same building likely has sawdust located beneath it; 6 • there is a history of subsidence beneath affected condominium structures in areas where sawdust, methane and hydrogen sulfide are present; • a heavy, thick layer of sod grass and top soil may be preventing natural venting of methane and hydrogen sulfide around the buildings from venting to the atmosphere;

2 See AR document 3 3 See AR document 4 See AR document 2 5 See AR document 5 6 See Figure 4 6. ERB Response Actions to Date (July 27- August 30, 2017)

Emergency response actions conducted since July 27, 2017 under the direction of the EPA On- Scene Coordinator include:

• fencing of condominium common areas containing elevated methane in surface soils; • ongoing positive pressure ventilation of two residential crawl spaces to which methane is migrating. This prevents potential for methane concentrations to reach an explosive range by diluting tern with fresh outside air; • deactivation of all potential ignition sources in crawl spaces (7) of the two structures with high methane in adjacent soils; • ongoing monitoring and investigation of the spatial extent and concentrations of methane and hydrogen sulfide in soils and groundwater within the residential area; • communication with condominium residents and Board of Directors; • coordination with Elmwood Twp. Fire Officials, Leelanau County Emergency Management, MDEQ, Michigan Department of health and Human Services (MDHHS), and ATSDR; • coordination of an "Area Wide "investigation into the source(s) and cause of methane and hydrogen sulfide generation and migration, including potential relationship with remedial cleanup activities or migration of methane or other substances injected to promote methanogenic de-chlorination at the up-gradient GTOS Site (see discussion below);7 • development of response alternatives, to remove high levels of methane from residential areas and if possible prevent future buildup of methane. This includes including conducting on-site pilot tests.

Investigation to date shows a strong correspondence between the location of buried sawdust and the occurrence of high methane and hydrogen sulfide in soils and residential crawl spaces at the condominium complex. A plausible explanation is that is that methane and hydrogen sulfide within the residential area is simply resulting from a localized, anaerobic degradation of sawdust buried beneath the shallow groundwater surface in the area of the condominium buildings and is accumulating around residential structures because a confining layer of thick sod is preventing its otherwise natural tendency to ventilate to the atmosphere. It is recognized, however, that it is necessary to evaluate any other potential sources/cause scenarios to guide and help ensure success of ongoing response measures. These include but may not be limited to the following scenarios:

• that methanogenic reactions induced at GTOS by EPA in 2015 in an attempt to augment de-chlorination of VOCs in groundwater has resulted in dissolved methane and hydrogen sulfide migrating downgradient in groundwater into the residential area. Concern that was expressed by MDEQ and EPA project managers about methane migration back in 2016 first led to the decision to monitor downgradient in the residential areas for methane (see First Five- Year Review).8 The resultant monitoring led to the discovery of

See AR document 8 See AR documents 6 and 7 methane in soil gas in 2016 near a building within a condominium complex. The possibility that such methane migration could have been facilitated by loss of hydraulic control described below is also under consideration;

• that that the additives used during the groundwater injections (bacteria, carbon and iron) introduced at the site to accelerate de-chlorination may have migrated downgradient during a period of time when extraction wells designed to control groundwater and chemical movement were offline for 6 weeks during late 2015 and early 2016, and that these nutrients may be contributing to methanogenic degradation of organic sources in the residential areas. These sources might include VOCs in groundwater from GTOS that is known to be present beneath the condos, or sawdust, also now known to exist beneath the condos, or both;

• that the methane is either a fugitive utility gas (ancient thermogenic gas) or a naturally occurring biogenic gas derived from the Devonian black shale foimation. This scenario seems the least viable and investigation to date suggests that these are not likely. Nevertheless, there are additional investigative steps that can be taken to rule them out as possibilities.

Please see Figure 3 for a depiction of site features referenced in the first three bullets above.

7. Release or threatened release into the environment of a hazardous substance, or pollutant or contaminant

A release of a pollutants, or contaminants is present due to the documented presence of methane and hydrogen sulfide in groundwater and surface soils near the Site. Methane has been documented to have migrated into the crawlspaces of residential structures built atop or adjacent to soils which contain dangerously high levels of methane and elevated levels of hydrogen sulfide.

While methane is not a CERCLA hazardous substance, at this Site it is a pollutant or contaminant under CERCLA. EPA determined by memorandum in 1986 that because methane was not listed or designated under any of the statutory provisions in section 101(14) of CERCLA, methane is not a hazardous substance for purposes of CERCLA. See, "CERCLA Removal Actions at Methane Release Sites," Memorandum from Henry L. Longest II, Director, Office of Emergency and Remedial Response, January 23, 1986, OSWER 9360.0-8 ("Methane Gas Memo"). Region 5 currently has no information to suggest that this deteimination has changed, and in addition EPA's superfund program operates based on the conclusion that methane is not a hazardous substance. However, methane is a "pollutant or contaminant" for purposes of CERCLA provided: 1) it is not naturally occurring methane gas found in or associated with petroleum deposits (e.g., methane gas emanating from a landfill); and 2) it otherwise meets the definition of "pollutant or contaminant" As documented in Sections 11.4, 11.5, 11.6, and 11.8, the methane gas found at the Site is almost certainly not a naturally occurring methane gas. In addition, EPA often treats methane as a pollutant or contaminant at sites where it is not naturally occurring and is not a petroleum fraction (e.g., methane produced by degradation of organic material in landfills). 9

Hydrogen sulfide is a CERCLA hazardous substance.

8. NPL status

The Site is currently on the CERCLA National Priorities List. It is listed as the Grand Traverse Overall Supply Superfund Site.

9. Maps, pictures and other graphic representations Site maps are included as Figures at the end of this memorandum.

10. Other Actions to Date

A. Previous actions In addition to actions documented in the Background Section (Section 11.2 and 11.3), EPA has also taken the following actions since 1997:

• Soil vapor intrusion studies at the on-site building and the elementary school. • Time critical removal action to construct a soil vapor extraction system at the Norris Elementary School, completed August 2005. • Time critical removal action to demolish the on-site GTOS commercial/industrial building and to excavate and dispose of the most highly contaminated soil under the building, conducted in 2007 through 2008. • Feasibility Report, completed 2007. • ROD, which selected a Site remedy including: (i) excavation of residual contaminated soils with a contingency for in situ treatment; (ii) groundwater pump and treat; (iii) continued operation of the SVE system under the school, and (iv) institutional controls, issued March 3, 2008. • ROD Amendment to increase the volume of contaminated soil to be excavated, completed April 2011. • Excavation and disposal of residual contaminated soils, commenced and completed during the autumn 2011; • Installation of groundwater extraction and treat system in 2012-2013.

9 CERCLA Section 101(33) defines "pollutant or contaminant" as: The term "pollutant or contaminant" shall include, but not be limited to, any element, substance, compound, or mixture, including disease-causing agents, which after release into the environment and upon exposure, ingestion, inhalation, or assimilation into any organism, either directly from the environment or indirectly by ingestion through food chains, will or may reasonably be anticipated to cause death, disease, behavioral abnormalities, cancer, genetic mutation, physiological malfunctions (including malfunctions in reproduction) or physical defolmations, in such organisms or their offspring; except that the term "pollutant or contaminant" shall not include petroleum, including crude oil or any fraction thereof which is not otherwise specifically listed or designated as a hazardous substance under subparagraphs (A) through (F) of paragraph (14) and shall not include natural gas, liquefied natural gas, or synthetic gas of pipeline quality (or mixtures of natural gas and such synthetic gas). The time critical removal action for which additional expenditures are sought by approval of this Action Memorandum is separate and distinct from the response actions summarized above, and represents a new response action.

B. Current actions

The groundwater extraction and treatment system summarized above is currently in O&M and is intended to operate until groundwater remedial action goals are met. The SVE system summarized above is also in O&M and is intended to operate until groundwater and soil vapor treatment goals have been satisfied. Region 5 also plans to conduct in situ treatment of residual contaminated soils in the saturated zone at the GTOS Parcel, commencing in summer 2014.

C. State and Local Authorities' Roles

1. State and local actions to date

MDEQ is currently represented in the group conducting Area Wide Investigation activities described above in Section 11.6.

MDHHS is monitoring response activities and is expected to provide human health risk assessment support on emissions related to venting of confined methane related degradation gases such as hydrogen sulfide and sulfur dioxide.

2. Potential for continued state/local response

State and local government assistance may be required during the removal action for those governmental functions that are inherently state and local. Given the exigency of the situation, neither the state nor local governments have the resources to conduct a removal action. The Elmwood Township Fire Department and Leelanau County Emergency Management Agency are expected to continue monitoring conditions and supporting response actions at the Site.

III. THREATS TO PUBLIC HEALTH OR WELFARE OR THE ENVIRONMENT, AND STATUTORY AND REGULATORY AUTHORITIES

The conditions at the Site present a threat to the public health or welfare, and the environment, and meet the criteria for a time-critical removal action as provided for in the NCP at 40 C.F.R. § 300.415(b)(2). These criteria include, but are not limited to, the following:

1. Threat of Fire or Explosion

High levels of hazardous substances, pollutants, or contaminants in soils largely at or near the surface that may migrate

Methane is a colorless, odorless, tasteless gas and can be referred to as natural gas, light carburetted hydrocarbon, firedamp, and marsh gas. High methane concentrations can cause oxygen-deficient atmospheres, flammable situations, or explosive environments. When methane enters the atmosphere as a point source, it can be readily ignited if the concentration exceeds 5 percent. Atmospheric methane can ignite at concentrations between 5 and 15 percent at Standard Temperature and Pressure (STP). Higher levels can quickly dilute to flammable levels. In either case, if methane is allowed to accumulate in an enclosed area, an explosive environment may develop. An explosive environment exists when a mixture of gases can self-propagate a flame throughout the mixture, independent of, and away from, the source of ignition. An ignition source can be an electrical outlet, pilot light, well pump, or match. Subterranean migration of methane can present a hazard at the ground surface, primarily in structures (buildings). Potential sources include: decaying organic matter, swamps, abandoned/improperly constructed gas wells, natural seeps, leaking pipes, landfills, and abandoned or active coal mines Entry into a structure can occur through cracks in the floor, along buried utilities, or as a dissolved component of water. When allowed to accumulate in a structure, an explosion may result.

In this case, methane has been determined to be present at levels as high as 70% in shallow soils adjacent to residential structures. (Please see Figure 4). As discussed above this results in potential for methane to be present at concentrations within its explosive range of 5-15% if it migrates to nearby confined spaces. Elevation of methane levels in such confined spaces (crawl spaces of two residential units) at the Site have been documented, but they are not within the explosive range. The highest crawl space level measured is at concentrations of less than 1% methane. Nonetheless, the migration pathway has been demonstrated to exist and it is necessary to eliminate possibility of gas levels rising into the explosive range1°.

2. Actual or potential exposure to nearby human populations, animals, or the food chain from hazardous substances or pollutants or contaminants;

Hydrogen sulfide has been documented to be present in shallow, near surface soils at the Site at levels as high as 70 ppm and can potentially migrate into adjacent residential structures. Figure 5 depicts hydrogen sulfide levels near the Site. Hydrogen sulfide is a heavier-than-air, colorless gas with a rotten egg smell. The odor threshold ranges from 0.0005 to 0.3 ppm. Hydrogen sulfide is released from volcanoes, sulfur springs, undersea vents, swamps, stagnant bodies of water, crude petroleum and natural gas, and manure or coal pits. It is also released by bacteria, fungi, and actinomycetes during the decomposition of sulfur-containing proteins and direct reduction of sulfate.

Inhalation is the most likely route of exposure for general population.

The main targets of hydrogen sulfide toxicity include the nervous system and respiratory tract. High-level exposure to hydrogen sulfide may cause unconsciousness and death; recovery from unconsciousness may be followed by persistent headaches, poor concentration ability and attention span, impaired short-temi memory, and impaired motor function. Respiratory distress, arrest, and pulmonary edema are associated with high-level exposure to hydrogen sulfide, and may be secondary to central nervous system depression or lack of oxygen in tissues. Cardiovascular effects have been observed following high-level exposure to hydrogen sulfide.

10 See AR document 1. A minimum risk level (MRL)of 0.07 ppm has been derived for acute-duration (<14 days) inhalation exposure to hydrogen sulfide. An MRL of 0.02 ppm has been derived for intermediate-duration (15-364 days) inhalation exposure to hydrogen sulfide.

3. High levels of hazardous substances or pollutants or contaminants in soils largely at or near the surface, that may migrate;

Both Methane and hydrogen sulfide are present in near surface soils near residential structures at the Site. Methane has been shown to have migrated into adjacent residential structures.

4.The availability of other appropriate Federal or state response mechanisms to respond to the release;

Local and State agencies do not have the resources to respond to this Site. EPA will discuss those agencies' abilities to conduct post-removal site control should they be deteimined to be necessary;

IV. ENDANGERMENT DETERMINATION

Given the conditions at the Site, the nature of the known and suspected pollutants, contaminants and hazardous substances, at the Site, and the potential exposure pathways described in Sections II and III above, actual or threatened releases of pollutants, contaminants, and hazardous substances from this Site, if not addressed by implementing the response actions selected in this Action Memorandum, may present an imminent and substantial endangerment to public health, welfare, or the environment.

V. ACTIONS AND ESTIMATED COSTS

1. Action description

EPA has begun action to mitigate methane and hydrogen sulfide found around occupied residential structures at the Site. Actions to date are described in Section 11.6. The following are additional removal activities which EPA intends to perfoim:

O development and implementation of a Health and Safety Plan and Sampling and Analysis Plans; • continued investigation of source and cause of methane and hydrogen sulfide generation; • continued characterization of full extent of methane and hydrogen sulfide presence in residential areas at the Site; O removal of methane and hydrogen sulfide buildup from soils around residential structures and from residential crawl spaces though implementation of a combination of the following approaches: o construction of passive ventilation systems; o active ventilation systems with scrubbing of gas to remove hydrogen sulfide; EPA is currently conducting on-site pilot testing of the ventilation approaches. A key parameter being evaluated is how to safely manage gas that is vented. This is particularly the case with hydrogen sulfide, which is very toxic at very low levels. Minimum Risk Levels (MRLs) for human populations are 70 ppb and 20 ppb for short term and intermediate human exposures, respectively.

Post Removal Site Control

EPA's removal action was/is being conducted in a manner not inconsistent with the NCP. The OSC has initiated planning for post-removal site control, consistent with the provisions of Section 300.415(1) of the NCP.

If an active ventilation approach with scrubbing of the exhausted gas is selected to ensure that these risk criteria for hydrogen sulfide are not exceeded (as a result of venting), a commitment for post-removal site control must be obtained for long-term operation of those systems. The OSC has initiated discussion of this topic with MDEQ, with EPA's RRD, and with the board of directors of the affected condominium complex.

If a source removal approach is selected, the need for post-removal site control will be greatly reduced. Excavation of sawdust, however, will require relocation of several utilities (gas, water, electric and communications) and will involve complicated excavation around occupied structures. Sheet piling and dewatering to protect building structural integrity and allow effective excavation will also be necessary.

EPA's response actions are being conducted in accordance with Section 104(a)(1) of CERCLA, 42 U.S.C. § 9604(a)(1) and Section 300.415 of the NCP, 40 C.F.R. § 300.415, to abate or eliminate the immediate threat posed to public health and/or the environment by the presence of the hazardous substances. No uncontrolled hazardous substances, pollutants or contaminants in residential indoor air are expected to remain at the Site after the removal action is completed.

A. Off-Site Rule

All hazardous substances, pollutants, or contaminants removed off-Site pursuant to this removal action for treatment, storage, and disposal shall be treated, stored, or disposed of at a facility in compliance, as determined by EPA, with the EPA Off-Site Rule, 40 C.F.R. § 300.440. At present, no off-site management of waste is contemplated.

2. Contribution to remedial performance

The proposed action will not impede future actions based on available information. The Site will be evaluated for future remedial activities. The threats posed by uncontrolled substances considered hazardous met the criteria listed in the NCP at 40 C.F.R. § 300.415(b)(2), and the response actions proposed herein are consistent with any long-tettn remedial actions which may be required.

3. Engineering Evaluation/Cost Analysis (EE/CA) Not Applicable.

4. Applicable or relevant and appropriate requirements (ARARs)

Applicable and relevant and appropriate requirements (ARARs) of federal and State law will be complied with to the extent practicable. The OSC requested identification of ARARs for work at the Site with MDEQ on September 12, 2017." ARARs identified by MDEQ in a timely way will be complied with to the extent practicable.

5. Project Schedule

The removal activities are expected to take 270 onsite working days. Routine system effectiveness sampling is expected to take upwards of 270 days to complete.

Estimated Costs The detailed cleanup contractor cost is presented in Attachment I and the Independent Government Cost Estimate is presented in Attachment III. Estimated project costs are summarized below:

Regional Removal Allowance Costs

Total Cleanup Contractor Costs $420,500 (Includes a 20% contingency)

Other Extramural Costs Not Funded from the Regional Allowance

Total START, including multiplier costs $ 65,256

Subtotal, Extramural Costs $ 485,756

Extramural Costs Contingency $ 121.439 (25 % of Subtotal, Extramural Costs)

TOTAL REMOVAL ACTION PROJECT CEILING $ 607,195

The response actions described in this Action Memorandum directly address actual or threatened releases of hazardous substances, pollutants, or contaminants at the Site which may pose an imminent and substantial endangerment to public health and safety and the environment. These response actions do not impose a burden on affected properties disproportionate to the extent to which the properties contribute to the conditions being addressed.

"See AR document 9 VI. EXPECTED CHANGE IN THE SITUATION SHOULD ACTION BE DELAYED OR NOT TAKEN

Delayed or no action at the Site increases the potential that additional hazardous substances, pollutants, or contaminants will be released, thereby further endangering, public health, welfare, or the environrnent.

VII. OUTSTANDING POLICY ISSUES

None.

VIII. ENFORCEMENT

For administrative purposes, infoimation concerning the enforcement strategy for this Site is contained in the Enforcement Confidential Addendum.

The total EPA costs for this removal action based on full-cost accounting practices that will be eligible for cost recovery are estimated to be $1,061,153.1

($607,195+ $48,000) + (61.96% X $655,195) = $1,061,153

IX. RECOMMENDATION

This decision document represents the selected removal action for the GTOS Site, located in Greilickville, Leelanau County, Michigan, developed in accordance with CERCLA, as amended, and is not inconsistent with the NCP. This decision is based upon the Administrative Record for the Site (Attachment II). Conditions at the Site meet the criteria for a removal action set forth at 40 C.F.R. § 300.415(b), and I recommend your approval of the proposed removal action.

The total removal action project ceiling, if approved, will be $607,195. Of this, as much as $543,939 may be used for cleanup contractor costs.

APPROVE DATE: Actin D ector, Superfund Division

Direct Costs include direct extramural costs and direct intramural costs. Indirect costs are calculated based on an estimated indirect cost rate expressed as a percentage of site-specific direct costs, consistent with the full cost accounting methodology effective October 2,2000. These estimates do not include pre-judgment interest, do not take into account other enforcement costs, including Department of Justice costs, and may be adjusted during the course of a removal action. The estimates are for illustrative purposes only and their use is not intended to create any rights for responsible parties. Neither the lack of a total cost estimate nor deviation of actual total costs from this estimate will affect the United States' right to cost recovery. DISAPPROVE DATE: Director, Superfund Division Figures: 1 — Site Region 2— Site Location 3- Consolidated Areas 4- Methane Results 5- Hydrogen Sulfide Results 6- Sawdust Footprint

Attachments: 1. Administrative Record Index 2. Enforcement Addendum 3. Detailed Cleanup Contractor Cost Estimate 4. Independent Government Cost Estimate 5. Environmental Justice Analysis

cc: B. Schlieger, EPA HQ Hardin D, EPA RRD, SR-6J Heidi Grether, Director, MDEQ, w/o Enf. Addendum Bill Schuette, Michigan Attorney General, w/o Enf. Addendum P.O. Box 30212 Lansing, MI 48909 Priyank Patel, MDEQ, w/o Enf. Addendum (p atelpl @mi. gov) David Kline, MDEQ, w/o Enf. Addendum ( [email protected]) L. Nelson, U.S. DOT, w/o Enf. Addendum Lindy [email protected] Lisa Quiggle, MDHHS, w/o EMI Addendum ([email protected]) M. Johnson, ATSDR- 4J, w/o Enf Addendum BCC PAGE HAS BEEN REDACTED

NOT RELEVANT TO SELECTION

OF REMOVAL ACTION FIGURES GTOS SITE Harbor West Marina Village Condominiums d mx 0912. 017 2 v ion_ Reg Site_ l_ Tig Memo ion_ t Ac 2- 091 017 \2 ing Sritst *ry 41 t -„ EFrontSl d \ Plann it 3 State St . I'.:TRAVERSE CITY4-. GIS mx \ t - Wes

bor GTOS/Harbor West VOC Har Legend and Methane Impacts

Approximate Grand Travers Overall

\ T11 30073_ Supply(GTOS) Site Location Figure 1 ts ec Glen Site Region

Proj Lake ;098 fr

HAGIS_ Aerial Source: ESRI World Imagery Service / USDA FSA NAIP2014 TETRA TECH EPA Contract No.: EP-55-13-01 Kb- TDD No.: 0001/505-0001-1703-006 Prepared For: U.S. EPA START Prepared By: MSG - KRB Coordinate System: NAD 1983 2011 StatePlane Michigan Central FIPS 2112 Ft Intl Date Saved: 9/12/2017 0 250 500 FORMER GTOS 6 BUILDING • Ornit0a5001, Feet (DEMOLISHED att DEC:, 2007) 00stfr10 Aerial Imagery Source: MIS Public Imagery Map Service I Unavailable date

HARBOR WEST - CONDOMINIUMS WEST BAY COVENANT CHURCH r .

\ Fig o Mem ion t HARBOR WEST Ac MARINA", 0912- \ 2017 ing

d \ Plann GTOS/Harbor West VOC

S1mx and Methane Impacts 1G1 t Nes I bor

Har Figure 2 Site Location \T1130073_ ts TETRA TECH Projec HAGIS_ HarborWesIGIS1mxd,Plannin - FORMER GTOS (DEMOLISHED DEC. 2007) BUILDING' USDA FSA-NAIP20160725 21 MethanedetectionswestofM-22representdissolved Notes: 1) MethanedetectionsinHarborWestCondominiumarea Aerial ImagerySource:ESRIWorldMapService- Methane MonitoringLocations Legend fa phase methaneingroundwater are soilvaporreadings e3 C13 ApproximateExtentofSawdust A `-lv • A , 0 GTOS/Harbor WestVOC Extraction WellLocation Greater than0.5%Methane Location Less than0.5%Methane (COCs) inGroundwater(March2017) (Dissolved and/orVaporPhase) (Vapor Phase) (Vapor Phase) Approximate AreaofDetectedMethane Remedial ActionMonitoringWell Extent ofTotalChemicalConcerns and MethaneImpacts Consolidated Areas Figure 3 TETRA TECH Feet 125 250 Legend

Soil Gas Monitoring Locations I=1 Lilits=1roposed E , 16, Greater than 0.5% Methane ;I:ProxImate Extent of • Less than 0.5% Methane wdus Sawdust Thickness -August 2017 Soil Borings (Hand Auger Ottgest 2017) 0 No Sawdust Encountered Utilities • < 0.5 ft Electronic line O 0.5.1.00 - Gas Une O 1.01 - 2.0 It sanitary Line O 2.01 -4.00 - Telecommunications Une - Unknown Linear Anomaly 40 >4.00 - Water Line Sawdust Thickness - Historic Borings GOES UTILITY 0 No Sawdust Encountered Hydrant

0 0.5 - 1.0

1.01 - 2.0f1 O * 2.01 - 4.0 ft

4.0 4.0 ft

50 100

Feet Aerial Imagery Source: ESRI World Imagery Map Service - USDA FSA - NA IR - 20160725

GTOS/Harbor West VOC and Methane Impacts

Figure 4 Methane Results

TETRA TECH Legend

▪ Piezometer Location with Detected H2S

▪ Piezometer Location ✓ Vapor Probe Location with Detected H2S

✓ Vapor Probe Location Temporary Vapor Monitoring Location with • Detected I-12S

• Temporary Vapor Monitoring Location

0 65 130

Feet

Aerial Imagery Source: ESRI World Imagery Map Service - USDA FSA NAIP - 20160725

REFERENCE MAP

241°Zot",,Erltr,

GTOS/Harbor West VOC and Methane Impacts

Figure 5 Hydrogen Sulfide Results

fit TETRA TECH Sawdust Thickness -August 2017 Soil Borings / Hand Auger C) No Sawdust Encountered e < 0.5 ft C) 0.5 - 1.0 ft ® 1.01 - 2.0 ft ® 2.01 -4.0 ft 0 > 4.0 5 Sawdust Thickness -Historic Borings <> No Sawdust Encountered 0 00.50 0 0.5 - 1.0 ft <> 1.01 -2.0 ft .2.01 -4.0 It ill > 4.0 ft C3 Approximate Extent of Sawdust IIM Limits of Proposed Excavation

0 50 100 Feet

Aerial Imagery Source: ESRI World Imagery Map Service - USDA FSA- NAIP -20160725

REFERENCE MAP

.1116b. a ficJIMIIMINI ZTZ,A= /MUNI 111•11111r A MINIM% 1, 11110001,2 111 I Michgan MIMI II? IIMIIIIII w Ion nay

GTOS/Harbor West VOC and Methane Impacts

Figure 6 , Sawdust Footprint

"Ft) TETRA TECH ATTACHMENT 1

U.S. ENVIRONMENTAL PROTECTION AGENCY REMOVAL ACTION

ADMINISTRATIVE RECORD FOR THE GRAND TRAVERSE OVERALL SUPPLY CO. SITE GREILICKVILLE, LEELANAU COUNTY, MICHIGAN

UPDATE 11 SEPTEMBER, 2017

NO. SEMS ID DATE AUTHOR RECIPIENT TITLE/DESCRIPTION PAGES

1 936303 9/1/2001 U.S. Dept. of the Public Technical Measures for the 129 Interior/Office of Investigation and Mitigation of Surface Mining Fugitive Methane Hazards in Areas of

2 936304 11/1/2016 ATSDR Public Toxicological Profile for 298 Hydrogen Sulfide and Carbonyl Sulfide

3 936305 3/27/2017 Hardin, E., U.S. Dollhopf, R., U.S. Email re: Methane at my GTOS 1 EPA EPA Site

4 936308 5/11/2017 Hardin, E., U.S. Guerriero, M., First Five-Year Review Report for 46 EPA U.S. EPA the Grand Traverse Overall Supply Co. Superfund Site

5 936309 5/31/2017 Townsend, S., Hardin, E., U.S. March 2017 Groundwater and 32 SulTRAC EPA Surface Water Data Summary Report

6 936307 8/1/2017 Mannik Smith Dollhopf, R., U.S. GTOS/HWC Site Historical 1 Group & Tetra EPA Research Index Tech Inc.

7 936310 8/1/2017 Mannik Smith Dollhopf, R., U.S. Objectives for Area Wide 3 Group & Tetra EPA Investigation Tech Inc.

8 936306 9/1/2017 Mannik Smith Dollhopf, R., U.S. Methane Investigation Summary 8 Group & Tetra EPA Tech Inc.

9 936311 9/12/2017 Dollhopf, R., U.S. Patel, P., MI DEQ Letter re: Applicable or Relevant 2 EPA and Appropriate Requirements (ARARs) Request NO. SEMS ID DATE AUTHOR RECIPIENT TITLE/DESCRIPTION PAGES

10 - - Dollhopf, R., U.S. Guerriero, M., Action Memorandum re: Request - EPA U.S. EPA for a Time-Critical Removal Action at the Grand Traverse Overall Supply Co. Site (PENDING ) ENFORCEMENT ADDENDUM

HAS BEEN REDACTED – SIX PAGES

ENFORCEMENT CONFIDENTIAL

NOT SUBJECT TO DISCOVERY

FOIA EXEMPT

NOT RELEVANT TO SELECTION

OF REMOVAL ACTION

ATTACHMENT 3

DETAILED CLEANUP CONTRACTOR ESTIMATE

HAS BEEN REDACTED – ONE PAGE

NOT RELEVANT TO SELECTION

OF REMOVAL ACTION ATTACHMENT 4

INDEPENDENT GOVERNMENT COST

ESTIMATE HAS BEEN REDACTED – TWO

PAGES

NOT RELEVANT TO SELECTION

OF REMOVAL ACTION ATTACHMENT 5

U.S. ENVIRONMENTAL PROTECTION AGENCY REMOVAL ACTION

ENVIRONMENTAL JUSTICE ANALYSIS FOR

GRAND TRAVERSE OVERALL SUPPLY SITE LEELANAU COUNTY, MICHIGAN

SEPTEMBER 2017 d c4-tg EPA KT:n"ndefe a I Protection EJSCREEN Report (Version 2017) 1 mile Ring Centered at 44.793472,-85.638554, MICHIGAN, EPA Region 5 Approximate Population: 1,182 Input Area (sq. miles): 3.14

— State EPA Region USA Selected Variables Percentile Percentile Percentile El Indexes EJ Index for PM2.5 27 34 23 EJ Index for Ozone 16 18 14 EJ Index for NATA* Diesel PM 52 59 43 EJ Index for NATA* Air Toxics Cancer Risk 28 34 29 EJ Index for NATA* Respiratory Hazard Index 40 47 37 EJ Index for Traffic Proximity and Volume 56 59 47 EJ Index for Lead Paint Indicator 35 38 21 EJ Index for Superfund Proximity 1 0 0 EJ Index for RMP Proximity 31 44 30 EJ Index for Hazardous Waste Proximity 56 63 48 EJ Index for Wastewater Discharge Indicator 43 51 35

El Index for the Selected Area Compared to All People's Blockgroups in the State/Region/US 100

75

50

25

44 1'414 44,sto. 04 4,00 '74")c., 'QV 4' 4 tsi,

k tat.,

Pi indexes

State Percentile oRegional Percentile USA Percentile

This report shows the values for environmental and demographic indicators and EJSCREEN indexes. It shows environmental and demographic raw data (e.g., the estimated concentration of ozone in the air), and also shows what percentile each raw data value represents. These percentiles provide perspective on how the selected block group or buffer area compares to the entire state, EPA region, or nation. For example, if a given location is at the 95th percentile nationwide, this means that only 5 percent of the US population has a higher block group value than the average person in the location being analyzed. The years for which the data are available, and the methods used, vary across these indicators. Important caveats and uncertainties apply to this screening-level information, so it is essential to understand the limitations on appropriate interpretations and applications of these indicators. Please see EJSCREEN documentation for discussion of these issues before using reports.

August 17, 2017 1/3 Ark EpA United States Environmental Protection EJSCREEN Report (Version 2017) 11110 AttencY 1 mile Ring Centered at 44.793472,-85.638554, MICHIGAN, EPA Region 5

Approximate Population: 1,182 Input Area (sq. miles): 3.14

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August 17,2017 1:18,056 0 0.15 0.3 0.0 rri Buffer Area a 0.25 9.5 1 Ism + Digitized Point Sxmes: Wt 1,02E. SelOrre, LS 55. tkrrilp. NUM/JEWS,. TAPP, Earl Mirl, ME11. Ein Arra Ifiarg Aron,/,. Esrmorn fin rr91959 7, AdarrylnIti. 140,. e 0211511:F9A; Oollta.11an. &Id re SS Lie I' CialIffranki

Sites reporting to EPA Superfund NPL 1 Hazardous Waste Treatment, Storage, and Disposal Facilities (TSDF) 0

August 17, 2017 2/3 United States E PA Environmental Protection Agency EJSCREEN Report (Version 2017) 1 mile Ring Centered at 44.793472,-85.638554, MICHIGAN, EPA Region 5 Approximate Population: 1,182 Input Area (sq. miles): 3.14

EPA %ile in Value State %ile in USA %ile in Selected Variables Region EPA Avg. State Avg. USA Avg. Region Environmental Indicators Particulate Matter (nn 2.5 in ug/m3) 6.93 9.14 4 10.1 1 9.14 10 Ozone (ppb) 40.8 38.1 94 37.6 97 38.4 80 NATA* Diesel PM (p.g/m3) 0.148 0.726 5 0.932 <50th 0.938 <50th NATA* Cancer Risk (lifetime risk per million) 22 31 9 34 <50th 40 <50th NATA* Respiratory Hazard Index 0.61 1.3 6 1.7 <50th 1.8 <50th Traffic Proximity and Volume (daily traffic count/distance to road) 3.6 570 13 370 9 590 9 Lead Paint Indicator (% Pre-1960 Housing) 0.15 0.39 27' 0.39 28 0.29 44 Superfund Proximity (site count/km distance) 0.69 0.14 96 0.13 97 0.13 97 RMP Proximity (facility count/km distance) 0.14 0.51 35 0.81 21 0.73 25 Hazardous Waste Proximity (facility count/km distance) 0.0057 0.072 3 0.091 1 0.093 1 Wastewater Discharge Indicator 6E-09 0.16 39 4.2 29 30 40 (toxicity-weighted concentration/m distance) Demographic Indicators Demographic Index 15% 30% 26 29% 30 36% 18 Minority Population 3% 24% 9 25% 13 38% 6 Low Income Population 27% 35% 41 33% 46 34% 43 Linguistically Isolated Population 0% 2% 62 2% 58 5% 44 Population With Less Than High School Education 4% 10% 24 11% 27 13% 24 Population Under 5 years of age 8% 6% 73 6% 70 6% 67 Population over 64 years of age 31% 15% 95 14% 96 14% 95 * The National-Scale Air Toxics Assessment (NATA) is EPA's ongoing, comprehensive evaluation of air toxics in the United States. EPA developed the NATA to prioritize air toxics, emission sources, and locations of interest for further study. It is important to remember that NATA provides broad estimates of health risks over geographic areas of the country, not definitive risks to specific individuals or locations. More information on the NATA analysis can be found at: https://www.epa.gov/national-air-toxics-assessment.

For additional information, see: www.epa.gov/environmentaljustice

EJSCREEN is a screening tool for pre-decisional use only. It can help identify areas that may warrant additional consideration, analysis, or outreach. It does not provide a basis for decision-making, but it may help identify potential areas of EJ concern. Users should keep in mind that screening tools are subject to substantial uncertainty in their demographic and environmental data, particularly when looking at small geographic areas. Important caveats and uncertainties apply to this screening-level information, so it is essential to understand the limitations on appropriate interpretations and applications of these indicators. Please see EJSCREEN documentation for discussion of these issues before using reports. This screening tool does not provide data on every environmental impact and demographic factor that may be relevant to a particular location. EJSCREEN outputs should be supplemented with additional information and local knowledge before taking any action to address potential EJ concerns.

August 17, 2017 3/3