Full opinion text
MEMORANDUM OF DECISION JOHN T. CURTIN, District Judge. In this action, originally brought in 1983 by the State of New York against the Solvent Chemical Company, Inc. (“Solvent”), and its parent company, ICC Industries, Inc. (“ICC”), pursuant to the Comprehensive Environmental Response, Compensation and Liability Act (“CERCLA”), 42 U.S.C. § 9601, et seq., the court conducted a non-jury trial on issues pertaining to the liability and equitable allocation of responsibility for costs incurred in remediating environmental contamination at Solvent’s property located at 3163 Buffalo Avenue in Niagara Falls, New York; adjacent property owned by the Olin Corporation (referred to as the “Olin Hot Spot” or simply, the “Hot Spot”); and Gill Creek, which flows through both Olin’s property and neighboring property owned by the E.I. du Pont de Nemours & Company (“DuPont”). The following constitutes the court’s findings of fact and conclusions of law with regard to these issues, in accordance with Rule 52 of the Federal Rules of Civil Procedure, based on the trial testimony and exhibits (including designated deposition testimony of 24 witnesses not appearing at the trial), the parties’ post-trial submissions and arguments, and the court’s prior rulings. I. FACTUAL AND PROCEDURAL SUMMARY A. The Three Neighboring Facilities The geographical area of concern in this case involves relatively contiguous parcels of property comprising three chemical manufacturing plant sites located in the midst of a sprawling heavy industrial area along the northern shore of the Niagara River in the City of Niagara Falls. The court’s analysis begins with a brief description of the three sites and the historical operations conducted there. 1. The Solvent Site Solvent’s property at 3163 Buffalo Avenue comprises 5.7 acres situated generally between the Olin chemical manufacturing plant site on the west, and the DuPont chemical manufacturing plant site on the east and south. It is bordered directly by Buffalo Avenue to the north, Adams Avenue to the south, DuPont Drive to the west, and a vacant parcel owned by DuPont to the east. Gill Creek, which flows from north to south through the Olin and DuPont plant sites, is located about 400 feet west of the 3163 Buffalo Avenue property (see December 1996 Record of Decision (“ROD”), Solvent Exhibit (“S-”) 1012). The manufacturing facility at the 3163 Buffalo Avenue address was originally built and operated by DuPont during World War II under a contract with the United States government to make “impregnite,” a chemical compound developed to treat Army uniforms for protection against exposure to poison gas. The plant was reactivated between 1951 and 1953 by the Hooker Electrochemical Company for impregnite production during the Korean conflict. The City of Niagara Falls purchased the site in 1972 and sold it to Solvent (id.). Solvent operated the chemical manufacturing plant at 3163 Buffalo Avenue from approximately 1974 to 1978. Its primary business function was to purchase lower grades of mixed chlorinated benzene material from other manufacturers or suppliers and refine this material into commercial grade products, such as various technical and refined grades of chlorinated benzenes and zinc chloride solutions. See State of New York v. Solvent Chemical Co., Inc., 218 F.Supp.2d 319, 323-24 (W.D.N.Y.2002); see also S-6040. This process involved the handling, storage, production, and use of several chemicals including benzene, chlorobenzene (also referred to as “monochlorobenzene”), 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene, 1,2,4-trichlorobenzene, 1,2,3-trichlorobenzene, petroleum products containing toluene, xylenes, ethylbenzene, and benzene, and zinc (DuPont Exhibit (“D-”) 14, 213; Trial Transcript (“Tr.”) 9/26/07, Item 1423 at 109). Solid residues from the refining process were accumulated in steel drums and disposed of off-site by approved waste disposal contractors (see Item 1328 (3/24/06 Decision and Order) at 43-44; see also S-6052; Tr. 1423 at 24-26). The Record Chemical Co., later known as Recochem, Inc., and its president, Joseph Kuchar, also operated the plant at the Solvent Site for a short period during the first three months of 1978 in order to ascertain the plant’s chlorinated benzene production capacity in anticipation of Recochem’s purchase of Solvent’s assets, which never materialized (see Item 1328 at pp. 68-69). Between approximately 1980 and 1983, two separate entities named Frontenac Environmental Services, Inc., leased a portion of the Site and used it as an unlicensed hazardous and industrial waste storage and transfer facility (D-14, p. 1-6). During that period of time, approximately 610,000 gallons of liquid chemical wastes, including chlorinated aliphatic solvents perchloroethene (“PCE”) (29,920 gals.), trichloroethene (“TCE”) (114,565 gals.), 1, 1, 1-trichloroethane (495 gals.), methylene chloride (1,100 gals.), chloroform, and carbon tetrachloride, as well as unspecified quantities of chlorinated and non-chlorinated waste products such as “halogenated solvents, electroplating sludge, spent pickle liquor, acid and caustic wastes, paint sludge, cyanides, etc.” (S-1012, p. 3), were managed or stored at the Site (D-91, 213; S-6053, 6054; Tr. 1423 at 26-27; Tr. 1425 at 61-63). 2. The Olin Site Olin’s Niagara Falls facility, located directly west of the 3163 Buffalo Avenue property, consists of two plants: Plant 1, which comprises six acres located west of Chemical Road; and Plant 2, which comprises sixteen acres located between Chemical Road to the west and Gill Creek to the east (S^1113). The area of Plant 2 between Alundum Road to the west, Buffalo Avenue to the north, Adams Avenue to the south, and Gill Creek to the east, is known as the “ARGC Area.” Olin also owns the property between Gill Creek and DuPont Drive directly adjacent to the 3163 Buffalo Avenue Property (S-4121; Tr. 1430 at 51, 62; Tr. 1433 at 81). Gill Creek runs from north to south through the Olin property and the DuPont property directly to the south, and empties into the Niagara River (Olin Exhibit (“0-”) 431). Olin or its predecessors have engaged in the production of various chemical products at the Niagara Falls facility continuously since 1897, with principal emphasis on electrolytic production of chlorine and caustic soda from sodium chloride (rock salt) using various modifications of the mercury cell/chlor-alkali process (0-223; S-4113; Tr. 1420 at 114, 121-22). Mercury cell operations historically took place at both Plants 1 and 2, but were confined to Plant 2 for the last 30 years of chlor-alkali production, which ceased entirely in 1991 (0-223). Olin also manufactured the pesticide benzene hexachloride (“BHC”), also known as hexachlorocyclohexane, in the southern portion of the ARGC Area of Plant 2 from 1950 to 1956 (S-4121; Tr. 1413 at 30-31; Tr. 1430 at 52, 62-63). By-products of Olin’s BHC production included trichlorobenzene, pentachlorobenzene, and hexachlorobenzene (Tr. 1413 at 31-35, 39-41; Tr. 1430 at 119-123,136). During this six-year period of operation, Olin generated approximately 4.5 million pounds of BHC and 5.5 million pounds of trichlorobenzene annually (Tr. 1413 at 38-41; S-6045). Olin’s BHC production ended in 1956 when the manufacturing plant was destroyed in an explosion (S-4016; Tr. 1440 at 12-13). 3. The DuPont Site From approximately 1896 to the present day, DuPont or its predecessors have owned and operated a chemical manufacturing facility situated on a 52-acre site located directly south of the Olin Site, and generally south and southwest of the Solvent Site (D-187; S-6014). During a 50-year period between 1925 and 1975, DuPont manufactured various chlorinated aliphatic compounds there (among other chemical products), including trichloroethene (“TCE”), tetrachloroethene (a/k/a perch loroethylene or “PCE”), cis-l,2-dichloroethane, chloroform, 1,1,2,2-tetrachlo-roethane (“1,1,2,2-TCA”), vinyl chloride, methylene chloride, and dichloroethene (Tr. 1413 at 16-17, 20-22; S-6039, 3024, 3025). On November 28, 1989, DuPont entered into an Order on Consent with the New York State Department of Environmental Conservation (“DEC”) requiring DuPont to perform certain remedial activities at its facility so as to “eliminate or mitigate, to the greatest extent practicable, the release and migration of contaminants into the environment” (D-106, p. 2). On January 3, 1990, the DEC issued a Record of Decision (“ROD”) outlining the remedial action for the DuPont facility. This remedy consists of a series of pumping wells in the shallow groundwater zone running along an east-west axis of the DuPont facility south and west of the Solvent Site, and a production well on Olin’s property for control in the deeper groundwater zones west of Gill Creek (see S-3021 at 15; see also Tr. 1432 at 118-19; Tr. 1442 at 66). There is no control of groundwater in the deeper zones on the DuPont East Plant, located east of Gill Creek and south and southeast of the Solvent Site and the Hot Spot (Tr. 1432 at 118-19; Tr. 1442 at 66-67, 69). B. Remedial Investigations at the Solvent Site In 1978, Solvent entered into a contract to sell the 3163 Buffalo Avenue property to Newco Chemical Waste Systems, Inc. (see D-4). In November 1978, RECRA Research, Inc. (“RECRA”), an environmental consulting firm, conducted an environmental survey on behalf of Newco, finding chemical contamination present on the site “to an appreciable extent,” and describing the conditions “to be quite serious and are expected to necessitate yet undefined abatement activities” (D-l). The RECRA report further stated that, “Gill Creek, immediately adjacent to the Solvent Chemical Plant, is also suspected of being highly contaminated with chlorobenzenes, as well as storm sewer lines leading from the Solvent Chemical property and discharging into Gill Creek” (id.). In November 1979, Solvent and Newco retained environmental consultant Roy F. Weston to conduct an investigation of the conditions at the Site and to determine the need for any remedial measures (see D-4). In a report dated February 1980, Weston described benzene and chlorinated benzene groundwater contamination in the overburden and shallow bedrock in the southwest quadrant of the Site (S-1001, pp. 19, 22). Dichlorobenzenes had the highest groundwater concentrations, ranging from 8,000 to 24,975 ppb (parts per billion) (id. at Table 2-3). Later in 1980, RECRA conducted a hydrogeological investigation of the Site on Solvent’s behalf “to expand on the work undertaken by Roy F. Weston, Inc., and to provide recommendations for remedial work to be performed, if deemed necessary” (S-1002, p. 1). In a Remedial Action Investigation Report dated December 3, 1980, RECRA confirmed the presence of elevated concentrations of benzenes and chlorinated benzenes in the soil and groundwater, as well as in the sewer lines passing beneath the site (see id. at pp. 67-72). RECRA recommended a number of remedial measures “to collect contaminated ground waters and provide reasonable containment of such ground water to the site proper” (id. at p. 73-78). Upon receipt and review of this information, the DEC requested further investigation to determine the extent of groundwater contamination and the scope of remedial work to be performed at the Site. As a result, a Phase I Study was conducted in the spring of 1983, and a Phase II Study was conducted in the summer of 1984, to gather additional data and evaluate remedial alternatives for the Site. Both studies were performed for the DEC by Engineering Science, in association with Dames & Moore (see D-ll). In 1985, the DEC listed the Solvent Site on the New York State Registry of Inactive Hazardous Waste Disposal Sites as Site No. 932096, designated as a class “2” site (see D-103, p. 3). At about the same time, the State also listed the DuPont Site on the Inactive Waste Disposal Site Registry as Site No. 932013, and the two Olin plants as Site Nos. 932051A and 932051 B (see D-103, p. 5). Beginning in late 1989, the environmental consultant firm Ecology and Environment, Inc. (“E & E”), conducted a remedial investigation at the Solvent Site at the DEC’S request, pursuant to a stipulated cost-sharing agreement entered between Solvent, ICC, and DuPont (along with other third-party defendants) subsequent to the commencement of this action. In November 1990, E & E submitted a Remedial Investigation (“RI”) report to the DEC (S-1005). The DEC then requested additional investigation and, when the parties could not reach a cost-sharing agreement, engaged another environmental consultant firm, Malcolm Pirnie, to conduct a Supplemental Remedial Investigation (“SRI”) and prepare a Feasibility Study (“FS”). The SRI report was completed and approved by the DEC in July 1995 (S — 1009; see also D-14), and the FS report was completed and approved in February 1996 (S — 1010; see also Tr. 1442 at 18-19, 22). In December 1996, after several years of additional site investigation and evaluation of remedial alternatives, the DEC issued the Solvent ROD outlining a detailed plan for the remedial action to be taken at the Site (S-1012). As explained in the Solvent ROD’s Declaration Statement, the DEC “selected an overburden containment remedy with a phased bedrock hydraulic control program for the Solvent Chemical site and associated groundwater” consisting of the following components: 1. Containment of highly contaminated soils on-site by placement of a permeable clean soil cover system. 2. Control and collection of contaminated overburden groundwater through construction and operation of an overburden (“A-zone”) collection system. 3. Installation of a phased bedrock hydraulic control system, including pumping wells installed and operated within the upper fractured bedrock (“B-zone”) to achieve hydraulic control over the highly contaminated groundwater found in the overburden and upper bedrock at both the 3163 Buffalo Avenue Property and in the vicinity of monitoring wells OBA-15A and OBA-3A located on Olin’s property (referred to as the “Olin Hot Spot”). 4. Treatment and disposal of pumped groundwater. 5. Implementation of a monitoring program to evaluate the effectiveness of the remedy. 6. Deed restrictions limiting future use of the Site. See S-1012, at pp. i-ii Solvent began the construction of the ROD-specified remedy at the Site in the fall of 1999 with the installation of a trench and pumping well system designed to collect groundwater from the A-Zone overburden soils both on the 3163 Buffalo Avenue Property and at the Olin Hot Spot, followed by the installation of a series of pumping wells designed to collect groundwater from the fractured bedrock in the B-Zone both on the 3163 Buffalo Avenue Property and at the Hot Spot (Tr. 1422 at 31-36). All of the contaminated groundwater pumped by the system is pre-treated in the on-site pre-treatment system and then discharged to the Niagara Falls Publicly Owned Treatment Works (“POTW”) pursuant to a permit (Tr. 1422 at 54; Tr. 1442 at 53-54). B-Zone aquifer testing began in the early spring of 2000, and continuous B-Zone pumping operations commenced in the spring/summer of 2002 (see Tr. 1442 at 71-79; Tr. 1413 at 63-64). As of June 30, 2007, Solvent had incurred $9,624,328 in connection with implementing the remedy for the Site and Hot Spot (Tr. 1422 at 106-07). C. The Lawsuit Meanwhile, in December 1983, the State of New York brought this action (referred to by the parties as “Solvent /”) against Solvent and ICC (among other settling defendants) pursuant to CERCLA and state statutory and common law seeking recovery of the costs incurred and expected to be incurred in responding to the release or threatened release of hazardous substances at or from the 3163 Buffalo Avenue Site (see Item 1; D-101). Beginning in June 1986, Solvent commenced a series of third-party contribution actions against more than 80 companies and individuals, including DuPont. In April 1997, Solvent and ICC entered into separate consent decrees with the State, in which Solvent agreed to implement the remedial measures outlined in the ROD (see Item 655), and ICC agreed to guarantee Solvent’s performance (see Item 652). Also in April 1997, DuPont entered into a separate consent decree with the State, in which DuPont agreed to pay $216,250 of the $865,000 reimbursement to the State for the costs incurred in investigating conditions at the Solvent Site (see Item 657). In an order dated October 8, 1997, this court approved entry of the Solvent, ICC, and DuPont consent decrees, effectively terminating the State’s involvement in the litigation. See State of New York v. Solvent Chemical Co., 984 F.Supp. 160 (W.D.N.Y.1997). In April 1998, Solvent filed a fifth amended third-party complaint (Item 746) seeking contribution pursuant to CERCLA from Olin and other third-party defendants for a share of the response costs Solvent has incurred and will continue to incur at the Site. Olin answered and asserted a counterclaim against Solvent, and filed a fourth-party complaint against ICC, seeking recovery of a portion of the response costs incurred in connection with the remediation of Gill Creek which Olin and DuPont conducted jointly in 1990-92 (see Item 809). DuPont has not sought recovery from Solvent or ICC for any of the response costs it incurred in connection with the Gill Creek remediation. In June 2001, after encountering the presence of chlorinated aliphatic compounds (including TCE, PCE, DCE, 1,1,2,2-TCA, vinyl chloride, and chloroform) at much higher levels than expected in the groundwater extracted during aquifer testing of the B-Zone pumping wells at the Site, Solvent commenced a new lawsuit (referred to by the parties as “Solvent II ”) against DuPont for contribution pursuant to CERCLA § 113(f)(1) and the common law, seeking equitable allocation of response costs incurred as a result of the alleged migration of these substances from the DuPont facility. Solvent II was subsequently consolidated with this action for all purposes throughout trial and appeal. II. THE TRIAL Following extensive discovery, dispositive motion practice, resolution of Solvent’s claims against all parties but Olin and DuPont, and referral of the remaining claims to a magistrate judge for one final, unsuccessful attempt at settlement, a non-jury trial was held over the course of 19 days in September, October, and November 2007. The trial was conducted primarily by electronic presentation of over 1200 exhibits consisting of drawings, photographs, charts, maps, correspondence, deposition transcripts, and other documents introduced during the live testimony of ten witnesses. The court received the parties’ post-trial submissions and motions, and heard summations and argument on November 19, 20, and 21, 2008. What follows next is the court’s effort to summarize the parties’ presentation of the facts in order to provide a relatively coherent groundwork for making the findings and conclusions required by the Federal Rules. A. Solvent’s Witnesses 1. Andrew H. Smyth Mr. Smyth was retained by Solvent as its hydrogeological expert to determine the nature and possible sources of contamination at the Solvent Site and Gill Creek. As set forth in his curriculum vitae (S — 6013), Mr. Smyth has an M.S. in Geology from New Mexico State University and a B.A. in Geology from Ohio Wesleyan University. He has over 17 years of experience as an environmental consultant encompassing geologic and hydrologic site assessments and has numerous professional registrations as a geologist and environmental professional. He is currently employed by TRC, an environmental engineering and consulting firm in Lowell, Massachusetts (Tr. 1413 at 10-11). In preparing his expert report, Mr. Smyth reviewed historical documents, investigative reports, regional and localized hydrogeological studies, well-monitoring data, and several other sources of information about the Site. He defined the term “NAPL” as nonaqueous phase liquid, which can be either lighter or heavier than water. Light nonaqueous phase liquids (or LNAPL), such as benzene, are generally lighter than water and tend to float on the water’s surface, while dense nonaqueous phase liquids (or DNAPL) are heavier than water and actually flow through the earth, often coming to rest on a low permeability medium like bedrock. NAPL contains higher concentrations of contamination than groundwater, in which the constituents tend to dissolve (Tr. 1413 at 12-16). S-6023 is a diagram of the DuPont Site, showing the area where the chlorinated aliphatics PCE and TCE were manufactured. The diagram also indicates the location of a “tank heel cleanout” area where DuPont removed 4300 cubic yards of soil contaminated with chlorinated aliphatics at levels which were not present anywhere on the Solvent Site (id. at 16-18). Based on his analysis of pumping well data and historical information regarding contaminant levels in groundwater migrating from the DuPont Site, Mr. Smyth calculated that about 2 million pounds of chlorinated aliphatics have been removed from the DuPont Site. According to Smyth, this is a significant amount, but very small in comparison to the contamination still remaining in the DNAPL and soil at the DuPont Site (Tr. 1413 at 18-19). S-6039 is a timeline Mr. Smyth created based on information obtained from a September 1989 report on an interim remediation program conducted at the DuPont Site which indicates various periods of operation during which chlorinated aliphatics were manufactured or used by DuPont (Tr. 1413 at 20-22). S-6031 is a map of the Olin Site which depicts the location of mercury cell rooms, a BHC plant area where chlorinated benzenes were produced and used, and a bedrock injection well where hydrochloric acid was injected into the B-Zone bedrock. This map also depicts the Hot Spot area in the northeast corner of the Olin Site and process sewers that emptied into Gill Creek (Tr. 1413 at 22-28). S-4071 is a more detailed depiction of the network of sewers in the area of Gill Creek. The historical information available indicates discharges of various contaminants into Gill Creek through these sewers from Olin’s production facilities, but there is no sediment sampling data or water quality information to confirm amounts or concentrations (Tr. 1413 at 28-30). S-6041 shows Olin’s historical chemical production and use of chemicals at the Niagara Falls facility. S-6033 is a process flow diagram created by Mr. Smyth depicting Olin’s BHC production operations at a facility located in the Plant 2 area near Gill Creek. This process, which took place for a limited time between 1950 and 1956, generated various chlorinated benzene materials. S-6030 and 6045 are process flow diagrams produced by Olin which depict a slightly different BHC production process than the one depicted in Mr. Smyth’s diagram (Tr. 1413 at 31-41). S-6018 is a cross-section diagram entitled “Simplified Bedrock Geology and Fracture Zones,” taken from the Record of Decision for the DuPont Site. Mr. Smyth used it to identify the water-bearing overburden and bedrock zones underlying the Solvent, Olin, and DuPont Sites, identified during various hydrogeological studies conducted in the area. As depicted on the cross-section, the uppermost layer of consists of approximately 12 feet of overburden aquifer, followed by approximately 150 feet of bedrock referred to generally as Lockport Dolomite. The bedrock is divided into fracture zones identified at various depths by the letters A, B, C, CD, D, E, F, and, finally, J. The J-Zone represents the base of the Lockport formation, below which is shale (referred to as the Rochester Shale) (Tr. 1413 at 48-50). S-6026 is a document taken from a regional groundwater assessment dated October 1992, performed on behalf of Olin and DuPont by Woodward-Clyde and Conestoga-Rovers consultants. It depicts groundwater elevations in the area of the Solvent, Olin, and DuPont Sites, along with some of the regional hydrogeological features influencing groundwater flow. Mr. Smyth identified the Falls Street Tunnel and South Side Interceptor sewer lines, which carry approximately 9 million gallons of water a day each in an east-to-west direction under city streets, and the Power Authority of the State of New York (“PAS-NY”) conduits, which carry water from the Niagara River north to the PASNY reservoir. He testified that this exhibit indicates a preferred groundwater flow path in the deeper bedrock zones (D-Zone and deeper) from the southwest to the northeast, with an arrow drawn directly from the DuPont Site, past the Olin BHC plant, under the Hot Spot, past the Solvent Site, and toward the exact location where the PASNY conduits intersect with the Falls Street Tunnel and South Side Interceptor sewer (Tr. 1413 at 50-54). S-6022 depicts the same general flow path for groundwater in the Upper Lock-port Dolomite (B-, C-, and CD-Zones). This drawing indicates that groundwater in the upper zones flows from a high elevation point at the DuPont and Olin Sites, through the Solvent Site and the Hot Spot, and directly toward the intersection of the Falls Street Tunnel and the PASNY conduits. According to Mr. Smyth, this intersection “is a major ground water discharge point for a huge section of the Lockport dolomite. A lot of the water is trying to get to that point as fast as it can” (Tr. 1413 at 55). S-6015 is a composite of information obtained from several different hydrogeological investigations, showing groundwater elevations in the A-Zone, which is the groundwater flow zone closest to the surface. The A-Zone includes both “saturated overburden” and the uppermost level of fractured, or “weathered,” bedrock (see Tr. 1415 at 16-21). S-6015 depicts a high groundwater level near the center of Olin Plant 1, with a flow direction toward the low water level northeast of the Solvent Site. According to Mr. Smyth, the elevation readings on this exhibit indicate that Gill Creek does not have an impact on the flow of groundwater through the A-Zone (Tr. 1413 at 56-61). On cross-examination by Olin’s counsel, Mr. Smith gave the opinion that chlorinated benzenes could travel in the A-Zone groundwater from the Olin Site to the Hot Spot through or under Gill Creek (Tr. 1415 at 26-29). S-6017 shows the same northeasterly flow of groundwater in the B-Zone, from a high point south and west of the Olin BHC plant area toward the Hot Spot and the Solvent Site. This information was obtained from a Woodward-Clyde Phase I study at the Olin Site, conducted in 1993 (before Solvent began its pumping program in 2002). Mr. Smyth testified that the elevations depicted on this exhibit indicate that neither the Buffalo Avenue sewer, running from east to west along the northern boundaries of the Solvent and Olin Sites, nor the DuPont Sewer, running from south to north parallel to and just to the east of Gill Creek, have any impact on the flow of groundwater in the B-Zone (Tr. 1413 at 62-65). S-6068 is a potentiometric surface map of the same area depicting B-Zone groundwater elevations and flow based on combined data from Solvent and DuPont investigations conducted in December 2006. According to Mr. Smyth, this exhibit shows that under pumping conditions, groundwater flows from the high point in the B-Zone aquifer, located on the DuPont Site in the area of the facility at which chlorinated aliphatics (PCE and TCE) were produced, and travels to the northeast across Gill Creek and on to the Solvent Site (Tr. 1413 at 65-67). S-6069 shows potentiometric surface readings in the B-Zone prior to commencement of pumping operations, and S-6070 shows potentiometric readings after 69 hours of B-Zone pumping at well PW-1, located in the southwest corner of the Site. Mr. Smyth testified that a comparison of these two exhibits shows that this high rate of pumping did not have much influence on the overall groundwater flow in the B-Zone aquifer at the Site, beyond a limited draw-down effect in an area of approximately 50 feet surrounding the pumping well (Tr. 1413 at 67-70). Based on these several groundwater elevation and flow path exhibits, Mr. Smyth gave the opinion that groundwater in the A-Zone flows from the Olin Site to the east and northeast toward the Hot Spot and the Solvent Site, and in the B-Zone the groundwater flows to the northeast throughout the areas of interest at the three sites. The B-Zone flow is not impacted by the Buffalo Avenue sewer, but there is not enough information on the exhibits discussed to determine the impact of the DuPont Sewer (Tr. 1413 at 70-72). On cross-examination by Olin’s counsel, Mr. Smyth testified that groundwater in the B-Zone flows primarily within the cracks and fissures in the bedrock between horizontal bedding planes, as well as in vertical fissures (Tr. 1415 at 18-21). He also testified that general hydrogeological principles regarding sewer lines as preferential pathways for groundwater flow would suggest that at least some of the groundwater from the Olin Site would travel north along the DuPont Sewer toward the Buffalo Avenue sewer and the wastewater treatment plant {id. at 30^40). S-6075 shows the thickness of fill material and lacustrine (lake) sediments at the Solvent Site, indicating a fairly thick (six to ten feet) sequence of low permeability materials in the overburden which would impede the flow of spilled liquids into the bedrock and cause pooling of DNAPLs (Tr. 1413 at 73-74). S-6019 is a bedrock elevation map of the entire three-site area, compiled from available well data with color-shaded areas indicating high-to-low elevation contours and computer-generated arrows indicating top of bedrock flow gradients. S-6071 is the same map without the elevation color shading but with the production facilities and buildings on the various sites highlighted. According to Mr. Smyth, the information on these exhibits shows that if NAPL was flowing along the top of bedrock, it would flow generally toward the Solvent Site (Tr. 1413 at 74-81). At the Olin Site, the arrows indicate that NAPL would flow from the location of the former BHC production plant south or southeast toward Gill Creek, and from the trichlorophenol and trichlorobenzene production areas north of the BHC plant toward the Hot Spot by traveling in fractures under Gill Creek (Tr. 1413 at 82-85). On cross-examination, Oliris counsel pointed out that the arrows on these exhibits indicate a NAPL flow trend from northeast of the BHC plant to the south, in the opposite direction of the Hot Spot. Mr. Smyth testified that while there were several factors of influence in this particular area (such as a depression in the elevation of the bedrock under Gill Creek near the Adams Avenue bridge, and the nature of the media in the DuPont Sewer bedding), the general trend reflected by all of the parties’ bedrock data remained consistent, showing the highest elevation on the Olin Site sloping toward the lowest elevation on the Solvent site (Tr. 1517 at 22-25). S-6027 is a map showing the location of groundwater monitoring wells in the entire three-site area. The vast majority of wells are located on the Solvent Site in the areas of tank farm, rail, and other operations, and there is also a dense network of wells at the Hot Spot. There are essentially no monitoring wells located in the areas of BHC and trichlorobenzene operations at the Olin Site, or in the areas of TCE and PCE operations at the DuPont Site. Mr. Smyth testified that if the object of well placement was to capture the highest potential sources of groundwater contamination without bias in the analytical data, the wells should be located directly in the area where the particular chemical production took place (Tr. 1413 at 85-88). S-6036 shows soil sampling locations for the entire three-site area. The vast majority of soil samples have been taken from the Solvent Site, with a large number of dots indicating soil sampling in the areas of former site operations, as well as in the area of the Solvent 18-inch storm sewer which ran from north to south along the western boundary of the Solvent Site, then west through the lower portion of the Olin parking lot and emptied into Gill Creek. The map also shows sparse soil sampling in the areas of operations at both the Olin and DuPont Sites. In Mr. Smyth’s opinion, this results in bias in the analytical data regarding contamination levels in the soil, as the placement of monitoring wells did with respect to groundwater contamination (Tr. 1413 at 89-94). Mr. Smyth testified that the purpose of installing monitoring wells is to characterize ambient groundwater concentration in the aquifer, unaffected by pumping activity. The area of characterization is limited to the flow path line that travels through the well under ambient conditions, resulting in a zone of influence of just a few inches-essentially, the width of the sand pack around the well. A pumping well pulls in water from a greater diameter, giving a composite sample of flow paths in a much broader area of the aquifer. Because groundwater generally flows downward from the upper to lower water-bearing zones of the bedrock, a monitoring well screened in the B-Zone will have very little information about the C-Zone, whereas a pumping well in the B-Zone could conceivably pull water from the C-Zone through vertical fractures in the bedrock. In Mr. Smyth’s opinion, pumping well data presents a better characterization of the overall quality of groundwater in the region than does monitoring well data (Tr. 1413 at 94-97). On cross-examination, Mr. Smyth agreed with Olin’s counsel that monitoring well data is of value because it represents the movement of contaminants through the aquifer at a specific location over time. A pumping well, which draws water from a much larger area than a monitoring well, can actually change the hydraulic regime of groundwater by pulling in contaminants from sources outside the normal flow path. In fact, the very purpose of a pumping well is to aid the cleanup objective by capturing the highest concentration of contaminants from as large an area of the site as possible. In Mr. Smyth’s opinion, pumping well data presents a more representative picture of the contaminants in the aquifer of interest because monitor well data does not reflect the movement of groundwater through the fractured bedrock (Tr. 1415 at 60-64). S-6021 is a graph prepared by Mr. Smyth as a summary of chlorinated aliphatics and chlorinated benzenes removed from the groundwater in the three-site area, beginning in 1940 when Olin began operation of its production wells, and continuing to approximately the time of trial. The graph shows a steady rise in the amount of chlorinated aliphatics being removed, with a noticeable upward turn beginning in 1991, when DuPont began operation of its shallow recovery well system; continuing in 1997 when Olin began operation of its shallow recovery well system; and a further spike in 2002, when Solvent began operation of its B-Zone pumping well system. The graph also shows chlorinated benzene removal at a very low rate throughout the entire period, with a slight increase in 2002 upon commencement of the Solvent pumping operations. According to Mr. Smyth, this exhibit represents the disparity between the large amounts of chlorinated aliphatics, as opposed to the much smaller amounts of chlorinated benzenes, being recovered by the pumping systems at the various sites (Tr. 1413 at 100-04). S-6043 is a map of the three-site area taken from a regional groundwater assessment performed in 1992 by Woodward-Clyde and Conestoga Rovers Consultants, showing various levels of chlorinated aliphatic contamination. According to Mr. Smyth, this exhibit shows widespread groundwater contamination over the entire area of study as the result of DuPont’s chlorinated aliphatic production (Tr. 1413 at 104-06). S-6038 is a map of the entire study area, prepared by Mr. Smyth from monitoring well results, showing 1,1,2,2-tetrachloroe-thane concentrations in the B-Zone groundwater. The highest concentrations emanate from the area of DuPont’s TCE and PCE manufacturing facilities, spreading to various locations in the Olin and Solvent Sites. TCE and PCE can be considered tracer chemicals for DuPont since, among the three companies, only DuPont manufactured these chemicals. According to Mr. Smyth, this exhibit shows that DuPont is the source of the chlorinated aliphatic contamination found at the Hot Spot and the Solvent Site (Tr. 1413 at 107-13). On cross-examination, DuPont’s counsel asked Mr. Smyth about D-240, which is a copy of a 1977 report by the International Trade Commission listing Hooker Chemicals & Plastics Corp. as the only manufacturer of 1,1,2,2-TCA in the United States at that time (Tr. 1420 at 16-17). He explained on redirect examination that the Hooker facility is located to the east of the Solvent Site, and there is no groundwater contour map or other evidence to suggest that materials from the Hooker facility could have migrated to the wells at the Solvent Site and Hot Spot (Tr. 1420 at 53-54). S-6025 is a graph and associated pie chart prepared by Mr. Smyth based on combined data obtained from the pumping wells at the Solvent Site and Hot Spot, showing average concentrations of contaminants extracted from the groundwater, divided by USEPA maximum contaminant levels. As demonstrated by the graph and pie chart, chlorinated aliphatics (TCE, PCE and vinyl chloride) represent the overwhelming majority of contaminants found in the water pumped at the Site and Hot Spot (Tr. 1413 at 113-17). S-6037 is a graph and associated pie chart, prepared from the same data as S-6025, showing straight concentrations of contaminants pumped from the wells at the Solvent Site and Hot Spot. As in the prior exhibits, the highest concentrations are chlorinated aliphatics. The pie chart suggests that chlorinated aliphatics represent about 65% of the contaminants extracted by the Solvent pumping wells (Tr. 1413 at 118-22). S-6024 is a pie chart comparison of chlorinated aliphatic and chlorinated benzene groundwater contamination, based on pumped well data from various reports on the groundwater remediation systems being operated at each of the Sites. According to the pie charts, chlorinated aliphatics represent 100% of the contaminant load at DuPont. At Olin and at the Hot Spot, chlorinated benzenes represent only a very small percentage (approximately 3-4%) of the contaminant load. At 3163 Buffalo Avenue, chlorinated benzenes represent approximately 98% of the contaminant load in the shallow trench (A-Zone), and chlorinated aliphatics represent approximately 70% of the contaminants being pumped from the B-Zone wells. The combined B-Zone influent, including both the Hot Spot and the 3163 Buffalo Avenue property, is approximately 60% chlorinated aliphatics and 40% chlorinated benzenes. In Mr. Smyth’s opinion, this information shows that the contaminants being pumped from the Olin Site are the same as the contaminants being pumped from the Hot Spot. The Solvent Site proper has a lot more chlorinated benzenes, but the overwhelming majority of contaminants being pumped from the B-Zone groundwater consists of chlorinated aliphatics (Tr. 1413 at 122-26). S-6067 contains pie charts comparing the ratios of trichloroethene and tetrachloroethane (the two most prevalent chlorinated aliphatics) found in the pumped well data at each of the three sites. The comparison shows that the ratios are very similar, indicating that the chlorinated aliphatic contamination at all three sites is coming from the same source (Tr. 1413 at 126-27). S-6042 is a pie chart comparison of the contaminants detected in the A-Zone shallow trench system at the 3163 Buffalo Avenue property. This system consists of three trenches installed down to the bedrock along the northern, western, and southern (including a portion of the southeastern) boundaries of the property to intercept the shallow groundwater in the overburden soils. The pie chart comparison shows that approximately 99% of the contaminants collected in the south and west trenches are chlorinated benzenes, while about 25% of the contaminants collected in the north trench are chlorinated aliphatics attributed to drum storage during the Frontenac periods of operation (Tr. 1413 at 127-30). S-6028 is a summary of NAPL data for the three sites, compiled by Mr. Smyth from several site investigation and analytical data reports, showing the presence of NAPL associated with chlorinated aliphatics, chlorinated benzenes, and BHC throughout the study area on a widespread basis. Mr. Smyth testified that the NAPL associated with BHC is traceable to Olin, and the NAPL associated with chlorinated aliphatics is traceable to DuPont (Tr. 1413 at 130-139). He also testified on cross-examination by DuPont’s counsel that, as stated in the SRI (see D-14 at p. 5-5), a quantitative assessment of contaminant loading based on NAPL migration would be difficult if not impossible due to several unknown factors, such as the unreported quantities of NAPL and the variable physical characteristics of the overburden and fractured bedrock (Tr. 1417 at 155-56). S-6044 is a map of the study area showing total chlorobenzene and chlorotoluene concentrations in the B-, C- and D-Zone groundwater. According to Mr. Smyth, this exhibit shows two large plumes joining together, one caused by the Solvent facility and one caused by the Olin facility (Tr. 1413 at 139-40). S-6032 shows monitor well results for perchlorate in the B-Zone groundwater. Mr. Smyth used perchlorate as a tracer to show that there is a flow path from Olin’s hypochlorite production areas west of Gill Creek to the Hot Spot wells located east of Gill Creek, which indicated elevated concentrations of perchlorate (Tr. 1413 at 140-43). On cross-examination, Mr. Smyth explained that Olin did not manufacture perchlorate, but it was a “decomposition product” of hypochlorite (Tr. 1417 at 28). His opinion that there was a groundwater flow path from Olin’s hypochlorite production facility to the Hot Spot, and that Olin was the source of not only perchlorate but all of the chlorinated benzenes detected at the Hot Spot, was based primarily on samples taken on one occasion in June 2007 from two of the six B-Zone monitoring wells showing concentrations of perchlorate .above detection limits (Tr. 1417 at 30-34; see also 0-608). He did not check to determine the groundwater impact of the long (over 60-year) history of perchlorate manufacturing operations at the nearby Occidental Chemical facility (Tr. 1417 at 37-43; see also 0-404, 605, 607 and 623). He testified that Occidental would be an unlikely source of the perchlorate detected at the Hot Spot because of its location, which the existing documentation shows as downgradient in all of the groundwater flow zones (Tr. 1420 at 65-67). S-6035 contains pie charts showing the relative proportion of chlorobenzene, dichlorobenzene, and trichlorobenzene materials detected in the groundwater influent from pumped wells at the Solvent and Olin Sites. According to Mr. Smyth, the pie charts show a close similarity in the proportions of materials being pumped at the Olin wells and the Hot Spot wells, indicating that the chlorobenzenes found at the Hot Spot came from the Olin facility (Tr. 1413 at 143-46). On cross-examination, Mr. Smyth testified that the data represented on this exhibit was obtained by averaging the results from two pumping wells at the Hot Spot, one screened in the A-Zone and one screened in the B-Zone. Since each zone has different gradient and media characteristics, and each carries different concentrations of contaminants, a pie chart showing the average of sampling results taken from the two zones presents a completely different picture than a pie chart showing sampling results from each (Tr. 1415 at 49-56). S-6046 is a map of Gill Creek and adjacent areas showing the location of downstream sediment samples taken during remediation activities in the late 1980s and early 1990s, along with a pie chart showing the makeup of the sampling results. Approximately 75% of the materials detected were PCBs associated with the DuPont facility, with approximately 5% attributed to chlorinated benzenes and the remaining 20% split between chlorinated aliphatics and BHC materials (Tr. 1413 at 146-47). S-6048 contains pie charts comparing the results of sediment samples taken from Gill Creek near Adams Avenue, along with the results of soil samples taken from the Olin Site and from the Solvent Site during removal of the 18-inch storm sewer. According to Mr. Smyth, this comparison indicates that the sediment samples taken from the creek are composed of approximately 70% trichlorobenzenes, associated with the Olin Site (Tr. 1413 at 147-52). This comparison did not include available data based on sediment samples obtained from inside the sewer itself, which indicated the presence of very high levels of chlorinated benzenes, including trichlorobenzenes (Tr. 1417 at 59-63). Mr. Smyth explained that he did not use this information because of the different environmental media for samples taken from the soil and samples taken from inside a pipe, and there was no available data from the Olin Site to allow for a reasonable comparison (Tr. 1420 at 74-75). During cross-examination, Olin’s counsel showed Mr. Smyth three separate tables from the 1995 Malcolm Pirnie SRI indicating the presence of trichlorobenzenes at very high levels in both the soil and groundwater at the Solvent Site. Specifically, 0-602 is a soil boring summary table showing concentrations of 1,2,3-trichloro-benzene at 640,000 ppb, and 1,2,4-trichlo-robenzene at 290,000 ppb, detected at a depth of between six and eight feet in the southwest portion of the Site where a tank farm was located and chlorinated benzene processing operations took place (see O-613). Mr. Smyth agreed that these are high concentrations, and that the 18-inch storm sewer provided a potential pathway for contaminants released from this area to find their way into Gill Creek (Tr. 1415 at 65-70). Mr. Smyth also agreed that the high levels of NAPL concentrations detected in the soil at these operational areas of the Solvent Site are associated with several documented surface releases and spills (see 0^149), and that these areas generally drained into the 18-inch sewer (Tr. 1417 at 45-48). 0-603 is a groundwater contaminant data summary based on samples taken from A-Zone monitoring wells showing a maximum level of 24,000 ppb 1,2,4-trichlo-robenzenes detected at MW-4A, located in the northwest corner of the Solvent Site— just across DuPont Drive from the Hot Spot and monitoring well OBA-3A (Tr. 1415 at 70-71; see also 0-615). 0-601 is a groundwater contaminant data summary based on samples taken from B-Zone monitoring wells showing a maximum level of 47,000 ppb 1,2,4-trichlorobenzenes detected at MW-2B, located in the southwest corner of the Solvent Site where product was loaded and unloaded from railroad cars (Tr. 1415 at 71-76). S-6047 is an allocation summary listing the contaminants found in the Gill Creek sediments. It was compiled by Mr. Smyth from the various studies performed in connection with the Olin/DuPont cleanup efforts in the late 1980s and early 1990s. The contaminants are given an allocation rating based on an assessment of “chemical harm” and “prevalence” under three separate DEC toxicity standards: 1985 Surface Water Criteria, 1999 Sediment Criteria — Human Exposure, and 1999 Sediment Criteria — Benthic Aquatic Toxicity. Under all three criteria, the overwhelming allocation percentages are attributed to PCB 1248, alpha-BHC, and beta-BHC, which are traceable to DuPont and Olin (Tr. 1413 at 152-55). S-6020 is an allocation summary listing the contaminants found in the soil at the Solvent Site, compiled by Mr. Smyth from the various site investigation reports. He assessed a “weighted impact” for each contaminant based on its prevalence and average concentration as compared to DEC cleanup criteria, and then normalized the weighted impacts to add up to 100% as a means of rating each contaminant against the other. Zinc was rated first, with an assessed allocation of 22.54%, followed by mercury (21.93%), 1,2,4-trichlorobenzene (13.77%), benzene (9.06%), 1,2-dichloro-benzene (4.10%), and other chlorinated benzenes, metals, and chemicals. S-6020A is the full list of contaminants found in the soil for which Mr. Smyth performed this allocation calculation (Tr. 1413 at 155-59). S-6066 is Mr. Smyth’s allocation analysis for contaminants detected in the groundwater at the Solvent Site and Hot Spot, using pumped well (as opposed to monitoring well) data from the Solvent and Olin sites. As he did with soil contaminants, Mr. Smyth assessed a weighted impact for each groundwater contaminant, divided into two categories: aromatics, allocated at 44.5%, and aliphatics, allocated at 55.5%. According to Mr. Smyth, using a weighted risk factor as opposed to straight volumetric division of harm resulted in a 10% decrease in the allocation percentage for aliphatics (Tr. 1413 at 160-62). On cross-examination by DuPont’s counsel, Mr. Smyth testified that he used pumped well data for the years 2002-04 in calculating the allocation percentages reported on S-6066. He was then shown D-222, prepared by DuPont’s expert, Dr. Faust, using B-Zone monitoring well data for the years 2004-06. This data reports concentrations and prevalence of chlorinated benzenes and other aromatic contaminants at 92.5%, and chlorinated aliphatics at 7.5% — significantly different than the allocation percentages reported on S-6066. Mr. Smyth explained that the monitoring well data used for this analysis represents a fraction of the contamination being intercepted by the pumping wells (Tr. 1420 at 40-46). S-6016 is a table showing Mr. Smyth’s assessment of contaminants detected in the shallow trench system at the Solvent Site. According to Mr. Smyth, this analysis shows that chlorinated aliphatics account for only a small amount of the contaminants being intercepted by the trench system (Tr. 1413 at 162-65). S-6065 is a summary of groundwater flow readings showing the total gallons of water removed from the shallow overburden (approximately 2.9 million gals.), Solvent Site bedrock (42.4 million gals.), and Hot Spot (43.3 million gals.) wells between March 24, 2003 and December 23, 2005 (Tr. 1413 at 165-66). S-6006 is a map of the three-site area showing mercury concentrations in the soil. The exhibit indicates a high level concentration of mercury in the southwest corner of the Solvent Site. In Mr. Smyth’s opinion, this was most likely caused by an accumulation of surface materials at the Solvent storm sewer (Tr. 1413 at 166-68). S-6072 contains two bar charts, one showing pumping data collected by TRC at the Hot Spot and the other showing pumping data from the Olin shallow groundwater remediation system located in the proximity of the BHC plant west of Gill Creek. According to Mr. Smyth, a comparison of the two charts shows very similar concentrations of contaminants being pumped at the two locations (Tr. 1413 at 168-71). S-6074 is a compilation of the two previous charts with a third bar chart showing concentrations of contaminants detected in the DuPont groundwater remediation system influent. According to Mr. Smyth, a comparison of these charts shows the similarity of the chemicals being detected in the influents at all three sites. He testified that the general groundwater containment and control systems deployed at all three sites are very similar, and that the Solvent system can be expected to remain in operation for hundreds of years due to the high level of contamination at the site (Tr. 1413 at 172-76). Mr. Smyth testified that, based on his review of the pumping data, 94% of the contaminants detected in the pumped wells at the Hot Spot are chlorinated aliphatics associated with DuPont. At the Solvent Site proper, as well as in the combined treatment system, chlorinated aliphatics make up the majority of the chemicals being pumped. According to Mr. Smyth, the presence of chlorinated aliphatics in the aquifer impacts the remediation of the site by lengthening the time for any natural bioremediation, leaching out of NAPLs, and eventual shutdown of the treatment system. He testified that if the system was treating chlorinated benzenes alone, it would be able to reduce contaminant levels to meet the standards for discharge to the Niagara Falls water treatment plant, and shutdown of the site treatment system, much sooner. In addition, the Solvent ROD requires Solvent to evaluate the impact of the treatment system on the concentrations of contaminants in the deeper bedrock zones. If the DEC finds the impact insufficient, it could require deeper wells and expanded pumping which, given the permeability of the deeper zones at the Site, would be likely to result in increased concentrations of chlorinated aliphatics in proportion to chlorinated benzenes (Tr. 1415 at 4-11). 2. Gary T. Hunt Mr. Hunt is a Qualified Environmental Professional, currently employed by TRC. His area of expertise pertinent to this case is the impact on the environment of emissions of toxic air pollutants from stationary sources. He was retained by Solvent to investigate and report on the potential sources of mercury found in the soils at the Solvent Site (Tr. 1420 at 91-93). He began his analysis by reviewing the available soil sampling data and documentation on the historical uses of the property since the inception of chemical production there in the early 1940s, finding no indication of activities that would account for the pervasive and widespread mercury contamination in the soils at the Site. His investigation of off-site sources revealed that Olin had operated a chlor-alkali production (“CAP”) facility to the west and upwind of the Solvent Site, which the open literature confirmed was a potential major source of mercury emissions. Based upon his review of the available data, historical documents, peer-reviewed literature, deposition transcripts, results of air emissions dispersion modeling, and several other sources of information (see S-6080), Mr. Hunt reached the conclusion that the mercury found in the soils at the Solvent Site can be attributed to emissions from the Olin CAP (Tr. 1420 at 95-102). S-6081 is a summary of the mercury detected in 21 soil samples collected at the Solvent Site in the 1990s. According to Mr. Hunt, this exhibit confirms the pervasive nature of the mercury contamination at the Site, at concentrations well above accepted background levels for urban soils in the United States (see S-6082). S-6006 is a contour map of the three-site area of study showing mercury soil concentrations as represented in the available soil data. Specifically, with respect to the Solvent Site, this exhibit shows the areas of concentrations of mercury as reported in the 21 soil samples represented on S-6081. According to Mr. Hunt, such pervasive contamination is unusual for a parcel of that size, particularly where there is no history of mercury use on the property. He identified Olin as the likely source, given the history of mercury use at its chlor-alkali production facility from 1897 through the early 1990s (see S-6041, 6083), the upwind location of the Olin facility as indicated by the “five year wind rose” represented on S-6006, and the lack of any information regarding mercury use at the DuPont Site (Tr. 1420 at 102-20). Mr. Hunt explained his understanding of the chlor-alkali cell process, which involved the use of mercury to function essentially as an electrode in the electrolytic production of chlorine, caustic soda, and other products. The mercury was not consumed and would generally remain in the cell to be re-used in the process, but it commonly escaped into the environment as a vented gas, as a component of the “brine mud” waste product periodically removed from the cell, as the result of volatilization due to spills, or through other fugitive releases (see, e.g., S-4086). Industry awareness of these problems eventually led to regulatory initiatives, resulting in the adoption in 1973 of national emission standards to specifically address mercury handling issues at chlor-alkali production facilities (Tr. 1420 at 122-32). Mr. Hunt discussed several other documents which he relied upon in reaching his conclusions about the source of the mercury contamination at the Solvent Site. Figure 3 from the October 1988 Woodward-Clyde Olin Site Groundwater Assessment (0-243) shows the location of five mercury cell rooms at the Olin Site. Mr. Hunt testified that four cell rooms, containing a total of more than 2000 production cells, operated for a period of approximately 60 years, and a fifth cell room containing 58 cells operated for a period of approximately 30 years. According to Mr. Hunt, these operations resulted in the release of a significant amount of mercury into the atmosphere and environment in the area of the Olin Site. For example, Figure 31 from O-243 shows mercury concentrations detected at elevated levels in soil borings in the area of Olin Plant 2, where three of the five cell rooms were located (Tr. 1420 at 134-42). S-4112 is an internal Olin memorandum dated August 14, 1991, entitled “Environmental Status of Niagara Falls Plantsite.” The authorship is not indicated on the memorandum itself, but Mr. Hunt identified the author as a Mr. Brown. The memorandum discusses several issues related to the anticipated partial or complete shutdown of the Olin Niagara Falls facility, including the cost of corrective action to address contaminated soils resulting from the mercury cell chlor-alkali operations (Tr. 1420 at 142-43). S-4113 is a February 1992 Woodward-Clyde RCRA Investigation Interim Report for the Olin Site, discussing at section 9.1.1 the evidence of widespread mercury contamination characteristic of emissions occurring over nearly 100 years of mercury cell operations at the Olin facility. S-4117 is the Woodward-Clyde Phase I Corrective Measures Study for the Olin Site, dated November 1993. Figure 4-1 depicts the soil management area, including the areas of both Plants 1 and 2 which contained the chlor-alkali cell rooms. According to Mr. Hunt, the remedial measures taken by Olin included some type of cover or cap of the soil management area (Tr. 1420 at 143-48). Mr. Hunt described the steps taken by TRC to determine the potential impact of mercury emissions associated with Olin’s chlor-alkali production activity on the soils at the 3163 Buffalo Avenue property. The principal analytic tool was an atmospheric dispersion modeling process using a computer program known as the Industrial Source Complex Model. The input parameters were based on available source identification information, mercury emission rates for cell room number five, meteorological data, representative ambient background levels for mercury in the air and soils in the study area, studies of environmental impacts at other chlor-alkali plants, and other pertinent data. The modeling program was run by TRC meteorologist John McCutcheon, and the results were plotted as predictive annual averages for mercury concentrations in both the atmosphere (see S — 6011) and soils (see S-6009). Based on these results, Mr. Hunt concluded that Olin’s chlor-alkali production was the most likely source of the mercury found in the soils at the 3163 Buffalo property (see Tr. 1420 at 148-56; Tr. 1421 at 2-43). On cross-examination, Mr. Hunt agreed that the modeling results for soil deposition indicated that the highest concentrations of mercury would occur on the northwest portion of the Solvent Site, whereas the actual results