| Date | Event | Source | Doc number |
| 1911 | Industrial processes at the Cabot Carbon site began. Different companies had control of the site throughout the years: Williamson Chemical Company, Florida Industrial Corporation and Retort Chemical Company) | Second Five Year report | 628 |
| 1916 | Industrial activities commence at Koppers site (with creosote impregnation) | Second 5 year report + 2010 FS | 628 |
| 1943 | Start using the South Lagoon (until 1975-1976) | 2010 FS | 497 |
| 1945 | Cabot Carbon purchased the Cabot portion of the site | Second 5 year report | 628 |
| 1954 | Koppers Company purchased the plant operation (Operated initially by The American Lumber and Treating Company) | Community relations plan | 638 |
| 1956 | Start using the North Lagoon (until the 1970s) | Proposed plan | 786 |
| 1960s | Treatment processes at the Koppers Site with chromated copper arsenate (CCA) | 2010 FS | 497 |
| 1961 and 1962 | Study conducted by UF => operating wood treatment facilities have a detrimental effect on Hogtown Creek | Community relations plan | 638 |
| 1966 | Cabot Carbon stop using the pine tar and charcoal generation facility in the southeast quadrant area | Community relations plan | 638 |
| 1967 | Cabot Carbon fined $100 for polluting Hogtown Creek and charged to cover the City’s cost of corrective action. | Second 5 year report | 628 |
| 1969 | Treatment processes at the Koppers Site with pentachlorophenol (penta) | 2010 FS | 497 |
| 1970s | Stop using the North lagoon to manage wastewater | Proposed plan | 786 |
| 1975-1976 | Stop using the South lagoon | Proposed plan | 786 |
| 1977 | FDER conducted biological survey for 2.8 miles in Hogtown Creek and found creek was devoid of life for 1.1 miles downstream of the 1977 illegal discharge from Cabot lagoons by new owner (construction of shopping center). | Second 5 year report | 628 |
| 1977 | Construction of the local shopping center disturbed the creosote deposits associated with the previous Cabot Carbon operations | Community relations plan | 638 |
| Dec-79 | EPA conducted a hazardous waste site investigation of the Cabot Carbon portion of the site to determine if leachate from the site had a detrimental effect on plants and other aquatic life in Hogtown Creek | Community relations plan | 638 |
| 1979 | Cleanup operations performed to remove some contaminated sediments from ditch from lagoon breach (no documented evidence of cleanup). | Second 5 year report | 628 |
| 1979 – 1981 | EPA and FDER conducted preliminary studies of the site(s). | Second 5 year report | 628 |
| 1982 | University of Florida conducted further evaluations on the Cabot site (to study options for treating the shallow well and ditch water at the site) | Second 5 year report + Community Relations plan | 628 |
| 1983 | Second EPA investigation: soil and groundwater from both sites; surface water and macroinvertebrate sampling in ditches; sediment sampling in Hogtown Creek, Main Street drainage system, and Koppers drainage ditch. | Second 5 year report | 628 |
| 1983 | An EPA site investigation determined an old lagoon area on the Koppers site to be a potential contaminant source area (southeastern portion of the site) | Community relations plan | 638 |
| Aug-83 | Cabot/Koppers site listed on NPL | Second 5 year report | 628 |
| 1984 | EPA granted Florida Department of Environmental Protection (FDEP) a cooperative agreement to perform the RI/FS. | 628 | |
| 1985 | Initial groundwater interceptor trench installed on Cabot portion of site | Second 5 year report | 628 |
| 1985 | FDER installed leachate collection system on Cabot site. | Second 5 year report | 628 |
| 1985 | Koppers Site investigation further evaluated the groundwater for TOC, chemical oxygen demand (COD), phenols, PCP, copper, chromium and arsenic. | Second 5 year report | 628 |
| 1986 | FDER completed study addressing potential environmental issues associated with widening North Main Street. | Second 5 year report | 628 |
| 1987 | Initial Remedial Investigation by IT Corporation completed and found deficient | Second 5 year report | 628 |
| Oct-88 | Cabot and Beazer East (aka BMS) enter into AOC to perform supplemental RI, a risk assessment and a FS | Second 5 year report | 628 |
| Nov-88 | EPA, the Koppers Company, and the Cabot Corporation signed an Administrative Consent Order requiring that the two Potentially Responsible Parties (PRPs) fund the supplemental RI/FS | Community relations plan | 638 |
| Sep-89 | Supplemental RI completed | Second 5 year report | 628 |
| February 1990, and May 1990 | Baseline Risk Assessment and FS completed | Second 5 year report | 628 |
| 27-Sep-90 | Record of Decision (ROD) signed | Second 5 year report | 628 |
| 1990 | Penta use was discontinued. Use of CAA at the site only | PP | 786 |
| 1991 | Cabot Carbon signs Consent Decree | Second 5 year report | 628 |
| Mar-91 | EPA issues UAO to Beazer and Koppers directing development of RD | Second 5 year report | 628 |
| 1992 | Use of Creosote totally phased out at the Koppers Site | 2010 FS | 497 |
| Mar-93 | Hydrogeologic Investigation of surface water body area, eastern portion of site, by Weston completed | Second 5 year report | 628 |
| Apr-94 | EPA amends UAO issued to Beazer and Koppers (requires additional Site characterization and development ofa Supplemental FS that included remedial altematives appropriate for the expanded extent of Site impacts) | Second 5 year report + PP | 628 |
| 1994 | Contaminated sediments removed from Northeast Lagoon, Cabot Carbon | Second 5 year report | 628 |
| Jan-95 | EPA signs Administrative Order on Consent for Removal Action at Cabot site | Second 5 year report | 628 |
| Jun-95 | Construction of the Groundwater Interceptor Trench completed (with the groundwater discharging to the principally-owned treatmentworks (POTW)) | Second 5 year report + Proposed plan | 628 |
| Sep-95 | Final Northeast Lagoon Closure Report for Eastern Portion, Cabot Carbon site, submitted to EPA | Second 5 year report | 628 |
| Jun-95 | Environmental Science and Engineering, Inc., (ESE) submits extraction well system rehabilitation and testing report for Koppers site | Second 5 year report | 628 |
| 1995 | Studying vertical groundwater circulation at the Former North Lagoon | PP | |
| 1995 | Groundwater ‘pump and treat’ system (shallow aquifer) installed at Koppers. | Second 5 year report | 628 |
| May-96 | Beazer submits Koppers site quarterly comprehensive monitoring report | Second 5 year report | 628 |
| Sep-96 | Hydrological assessment report by Stidham completed | Second 5 year report | 628 |
| May-97 | Cabot submits groundwater remedial report for eastern portion (Cabot Carbon) | Second 5 year report | 628 |
| Aug-97 | Beazer submits Closure Report for former creosote treatment bldg 2A | Second 5 year report | 628 |
| 1997 | Beazer completes an Interim Remedial Action by removing the former creosote treatment building and performing in place closure of the buildings’ foundation | Second 5 year report | 628 |
| Jan-97 | Beazer submits a SFS | Second 5 year report | 628 |
| Sep-99 | Beazer submits RSFS Volume 1 and 2 | Second 5 year report | 628 |
| Mar-01 | EPA signs Initial Five-Year Review | Second 5 year report | 628 |
| May/June 2001 | EPA submits proposed remedy plan based on (revised) SFS; Plan is rescinded (assumption: the Hawthorn was a “barrier” to downard migration of contamination into the Floridan) | Second 5 year report | 628 |
| Jun-01 | Beazer conducts further studies to characterize Hawthorn clay and develop a database of local private wells in the vicinity. | Second 5 year report | 628 |
| March, April 2002 | Beazer conducts additional field investigations to characterize the Hawthorn Group and aquifer (Confirmed that Hawthorn is not a confining clay unit, and therefore, downward migration of contamination into Floridan possible). | Second 5 year report | 628 |
| Sep-02 | Beazer report on Field investigations to further characterize Hawthorn Group. Significant groundwater contamination of creosote and petroleum hydrocarbons was found up to 90′ below ground surface, and below several clay layers. | Second 5 year report | 628 |
| April – June 2003, and November 2003 | Beazer conducts further field investigations to further characterize Hawthorn Group and Floridan aquifer water quality and flow direction. Mail survey of private wells is completed. Floridan aquifer and Hawthorn aquifer groundwater contamination is confirmed. | Second 5 year report | 628 |
| October, November 2003 | Gainesville Mayor and GRU send letters to EPA urging remediation of Koppers. | Second 5 year report | 628 |
| October – December 2003, and April 2004 | GRU installs and samples sentinel wells between Koppers site and Murphree wellfield. One well had arsenic contamination above MCL. High levels of arsenic detected; but concentrations are decreasing over time. | Second 5 year report | 628 |
| 2004 | Recovering DNAPL manually by periodic bailing in HG monitor wells since 2004 | PP | 786 |
| Feb-04 | Beazer conducts water quality testing in 8 offsite shallow private and one deep Floridan aquifer well. Arsenic was detected in one shallow well; and low levels of contamination detected in the Floridan well. | Second 5 year report | 628 |
| March, April 2004 | County and City Commission approve resolutions urging EPA to expedite source remediation efforts and take actions to address contamination discharges to Floridan and Intermediate aquifers. | Second 5 year report | 628 |
| Mar-04 | EPA directs Beazer to develop a Floridan Aquifer Monitoring Plan and to expedite and complete field activities to further characterize source areas. | Second 5 year report | 628 |
| January – June 2004 | Beazer works on developing new groundwater model for Koppers site using GRU, county and recent new data (=> states would take over 100 years for Koppers Site groundwater contamination to reach Murphree wellfield) | Second 5 year report | 628 |
| Jun-04 | Floridan Aquifer Monitoring Plan developed by Beazer. | Second 5 year report | 628 |
| Jun-04 | EPA directs Beazer to submit all data from field investigations, and to develop project plan to address deep contamination in source areas, and submit a project schedule for remediation by August 30, 2004. | Second 5 year report | 628 |
| Jul-04 | Beazer presents results confirming contamination in Floridan aquifer wells in source areas (=> found creosote in upper and lower Hawthorn, with North Lagoon having highest concentrations). Requests extension of August 2004 deadline to December 2004. | Second 5 year report | 628 |
| Aug-04 | Beazer submits Proposed Interim Measures/Remedy Pilot Approach. (=> Floridan well FW-6 has high levels of naphthalene and creosote related constituents) | Second 5 year report | 628 |
| Aug-04 | Contamination found in Floridan aquifer well above drinking water standard. | Second 5 year report | 628 |
| 2004 – 2005 | Surficial aquifer DNAPL recovery pilot test (=> Pilot recovery test at PW- 1 at Koppers was not successful in removing mobile DNAPL. During 5 month period, 89 gallons of DNAPL recovered with 335,169 gallons water pumped) | Second 5 year report | 628 |
| 2005 | Intermediate aquifer DNAPL recovery pilot test (=> workplan submitted to EPA) | Second 5 year report | 628 |
| Jan-05 | Source removal assessment report (=> Beazer concluded source removal options infeasible; but EPA and stakeholders did not agree all options are infeasible | Second 5 year report | 628 |
| 2005 | Various Floridan aquifer monitoring plans are developed by Beazer (=> most plans are disapproved by EPA) | Second 5 year report | 628 |
| Apr-05 | Chemical Oxidation Pilot Plan submitted (=> disapproved by EPA) | Second 5 year report | 628 |
| May-05 | Arsenic in Groundwater study by Dr. Pichler (=> results of study are inconclusive) | Second 5 year report | 628 |
| Jun-05 | Electrical Resistivity Report (=> Disapproved by EPA and stakeholders) | Second 5 year report | 628 |
| Aug-05 | EPA prepares Revised Floridan Aquifer Monitoring Plan, and Beazer agrees to implement. | Second 5 year report | 628 |
| Late 2005 | Floridan aquifer monitoring wells installation begins. | Second 5 year report | 628 |
| Sep-05 | Remedy Status and Expanded Remedy Performance Monitoring Report (=> Reviewed past 10 years of monitoring data) | Second 5 year report | 628 |
| Nov-05 | Evaluation of the Capture Effectivenessof the GroundwaterExtraction System at Koppers (=> Indicates that offsite migration of contaminated groundwater is occurring) | Second 5 year report | 628 |
| Jan-06 | Second five-year review begins. | Second 5 year report | 628 |
| Feb-06 | Preliminary sampling and analysis results indicate contamination in Floridan wells at depths in the deepest zones of the drilled wells (approximate depths of 90′ below top of Floridan, about 200′ below ground surface). | Second 5 year report | 628 |
| Feb-06 | Review and Recommendations Report for the Cabot Carbon/Koppers Superfund Site (=> A long list of investigations and work to accomplish before the FS can be finalized) | Second 5 year report | 628 |
| Apr-06 | Second five-year review signed | Second 5 year report | 628 |
| 2006 | On-Site surface and subsurface soil was sampled to supplement prior characterization of COC concentrations | 2010 FS | |
| Early 2007 | Floridan Aquifer multilevel wells sampling groundwater zones depths from 200 to 350 ft below land surface installed by Beazer in early 2007 at the northern boundary of the Koppers site to investigate the potential for contamination migration in the deeper Floridan Aquifer zones, assess the hydraulic properties of the deeper aquifers and detect and assess the vertical extent of contamination in the Floridan Aquife | Alachua CHD | |
| Aug-07 | Additional surficial aquifer groudwater monitoring (No measurable DNAPL was recovered) | 2010 FS study | 497 |
| Aug-09 | HHRA for on site soils and sediments was submitted (includes both a deterministic (traditional) evaluation of potential risks and a more quantitative probabilistic model for potential risk evaluation) | PP | 786 |
| 2009 | Evaluation of potential ecological risks associated with sediments | PP | 786 |
| 2009 | Surficial Aquifer groundwater extraction system was upgraded to increase pumping capacity and capture contaminated groundwater through placement of recovery trenches next to the 4 principal source areas | Proposed plan | 786 |
| Late 2009 | Koppers ceased wood treatment operations | 2010 FS study | 497 |
| 2009-2010 | Additional surficial aquifer groudwater monitoring | 2010 FS study | 497 |
| 31-Mar-10 | Beazer purchased property from Koppers Inc to facilitate remediation | 2010 FS study | 497 |
| May-10 | Finalization of the revised FS | PP | 786 |
| May-10 | 2009 HHRA was updated to take into account a change in land use and to incorporate comments received on the earlier version | PP | 786 |