Monthly Archives: September 2010

Site history

The Cabot Carbon/Koppers Site is located in the Northern part of Gainesville and encompasses about 170 acres. The Superfund site was originally two sites: Cabot Carbon and Koppers.

Activities at the Cabot Carbon site

The Cabot Carbon site covers 49 acres in the Southern portion of the site. In 1911, chemical industrial activities began at the Cabot Carbon site. However, it was only in 1945 that Cabot Carbon purchased that section of the site to generate pine tar and charcoal.

In 1967, industrial processes stopped at the Cabot Carbon property and the property was sold to Raymond Tassinari, a local private investor. During the same year, the impoundment walls were breached resulting in the discharge of contents into the surface ditch and eventually into Hogtown Creek. The same year, Cabot Carbon was fined $100 for polluting the Creek.

In 1977, the property was sold to Harry S. Hamilton who begun the construction of current commercial properties. These constructions have disturbed creosote deposits associated with past activities. In the same year, the Florida Department of Environmental Regulation (FDER) has conducted a biological survey in Hogtown Creek and found that the creek was devoid of life for 1.1 miles downstream. In 1979, cleanup operations were performed to remove some contaminated sediments from the ditch at the Cabot Carbon site. However, there is no documented evidence to support that claim.

Activities at the Koppers Site

The Koppers site encompasses approximately 86 acres. In 1916, industrial activities with creosote impregnation started at the Koppers Site. The South and North lagoon were active from 1943 and 1956 respectively.  After these lagoons closed in the 1970s, they were covered and graded. In the 60s, creosote was progressively replaced by solutions of Chromated Copper Arsenate (CAA) and pentachlorophenol. At the beginning of the 1990s, pentachlorophenol and creosote were totally phased out. Only CAA was continued to be used to treat wood until Koppers closed in 2009.

Investigations and Remedial actions

Pre-1990 ROD Actions

Between 1979 and 1981, EPA and FDER conducted preliminary studies of the Cabot / Koppers site. At the Cabot site, the shallow groundwater was found to be contaminated; soil, surface water and sediments in ditch and Hogtown Creek.

In 1982, University of Florida conducted further evaluations on the Cabot site and found contamination of the shallow.

In 1983, the EPA has conducted further investigations. A second investigation of the Cabot and Koppers sites found soil and groundwater contamination. Macroinvertebrate sampling has confirmed contamination of the North Main Street Ditch. Surface water sampling of the Main Street Ditch showed contamination with organic compounds associated with destructive distillation and creosote wood preserving processes. Later that year, Cabot Carbon / Koppers Site was listed on the National Priorities List.

In 1984, the Florida Department of Environmental Protection (FDEP) was granted by the EPA to perform a Remedial Investigation and a Feasibility Study. A year later, two remedial actions were undertaken at the Cabot Carbon site: installation of an initial groundwater interceptor trench and a leachate collection system. The Initial Remedial Investigation (RI) was completed in 1985 but was found deficient.

In 1988, Cabot Corporation and Beazer East and Koppers Company signed an Administrative Order of Consent requiring that the two Potentially Responsible Parties (PRPs) fund the supplemental Remedial Investigation and Feasibility Study (FS).

In the next two years, the Remedial Investigation, a baseline Risk Assessment and the Feasibility Study were completed. In 1990, the Record of Decision (ROD) was issued and signed.

Post ROD actions

Cabot Carbon

In 1991, Cabot Carbon signs the Administrative Order on Consent (AOC) which requires implementation of the ROD-required actions (remedial design). Supplemental investigations and studies were required related to affected soils in the Northeast Lagoon; and the former Cabot production well location. The remedial actions included the installation of groundwater interceptor trench and excavation and off-site removal of contaminated soil within the Northeastern Lagoon (both completed in 1995).


In 1991, The EPA issued a UAO (Unilateral Administrative Order) to Koppers to conduct data acquisition and site characterization for remedial design. These investigations have shown that contamination at the source areas of the Koppers site was greater than at the time the ROD was issued (presence of DNAPLs below the groundwater table, greater volume of contamination). Therefore, it was important to reevaluate the selected ROD remediation strategy and technologies.

In 1994, the EPA amends the UAO by requiring Koppers to perform additional site characterization and develop a Supplemental FS that includes remedial alternatives appropriate for the expanded extent of the site impacts.

In 1995, the groundwater ‘pump and treat’ system is installed for the surficial aquifer with 17 extraction wells (extraction rate of 3 gallons per minute). It was designed to mitigate off-site migration but results are negative. In 2009, the extraction groundwater system was improved to increase the pumping capacity and the contaminated water is captured through the installation of recovery trenches.

In 1997, the supplemental FS was completed. In 1999, the revised FS was issued to incorporate comments from the EPA and FDEP. The latter FS took into account the expanded extent of the site impacts but did not considered contamination within and below the Hawthorn Group.

Investigations in 2003, 2004 and 2006 have shown the presence of dense non-aqueous phase liquids (resulting from creosote use) in the Hawthorn group. Moreover, contamination has also been observed deeper in the Upper Floridan Aquifer.

In 2001 and in 2006, the EPA has issued the 5 year reviews. The last 5 year review (2006) supports additional investigations to carry the selection of a new remedial strategy to address site impacts.

In March 2010, Beazer purchased the property from Koppers to facilitate remediation. The final Feasibility study was issued in May 2010 which developed and evaluated remedial alternatives for the Koppers site. In July 2010, the EPA has issued a Proposed Plan for Koppers. The public comment period was extended to October 15th 2010.

Off-site Sediments

Contaminated sediments in Hogtown and Springstead creeks can be attributed to activities (both historic and current) at the Cabot Carbon and Koppers wood-treatment facilities, which are adjacent to each other. They occur mainly in two forms:

  • Tar-like material released from Cabot Carbon operations.
  • Dioxins associated with stormwater runoff from Koppers.

Cabot Carbon. In 1961-62, the University of Florida conducted a study concluding that current wood-treatment operations were having a detrimental effect on Hogtown Creek, primarily from Cabot Carbon.  In 1966, Cabot Carbon ceased operations. In 1967, the new owner dug a ditch and released 1,400,000 gallons of waste liquor (tar-like material) from some of the waste lagoons. He was fined $100 for polluting Hogtown Creek and charged to cover the City’s cost of corrective action. The Florida Department of Environmental Protection  conducted a 2.8-mile-long biological survey of Hogtown Creek and found the creek was devoid of life for 1.1 miles downstream of the 1967 illegal discharge. These tar-like materials have persisted in sections of the creek sediments.

Koppers. On-site soils and sediments at the Koppers site are contaminated with dioxins (link). A drainage ditch runs through the site and discharges stormwater into Springstead Creek. Because there is limited ground cover, dioxin-contaminated surface soils are present in runoff during storm events.

Sediment Investigations

Alachua County Environmental Protection Department (ACEPD) has completed two phases of investigation and has identified areas impacted by tar-like material that has high concentrations of PAH compounds (link to definition of PAHs). Dioxins were detected in stormwater runoff from the Koppers site, and in surface sediments downstream.

These two sources of contamination impacted different sections of the creeks above levels considered protective for ecological receptors – and the dioxins were detected above residential soil criteria in an area where the sediments are frequently exposed.

link to studies: 529, 567, 571, 572, 603 + map and tar removal doc

What Remedy Is Proposed?

EPA’s Proposed Plan offers the following remedies for surface water and sediment in Hogtown and Springstead Creeks:

  • On-site detention basin to mitigate ongoing impacts.
  • Excavation and removal of impacted sediment in excess ecological criteria (transporting and consolidating the sediments on-site).
  • Monitored natural recovery of remaining impacted sediment until concentrations reach criteria or background.


Cabot Carbon has already submitted a work plan to remediate the sediments contaminated with the tar-like material. The EPA Proposed Plan states that Koppers will work jointly with Cabot to remediate the sediments. Many concerns have been raised about bringing these contaminated sediments onto the Koppers site to be consolidated in the containment area.

The cleanup criteria stated in the EPA Proposed Plan is focused on ecological risk. Typically, ecological-risk criteria are lower for sediments than criteria for protection of human health. However, human health criteria should also be included in the EPA’s Final Plan and Record of Decision.


Koppers Onsite Soil

Surface Soil Concentrations

As a result of the activities at the Koppers Site over the past 90 years, the chemicals used in treating wood have contaminated surface and subsurface soil. The primary chemicals of concern for risks associated with directly contacting the contaminated soils include arsenic, PAHs, and dioxins.

Currently, surface soils over most of the Koppers property exceed commercial/industrial soil cleanup target levels (SCTLs). In the western portion of the site, the contamination appears to be primarily near the surface (upper 2 feet). In some areas, particularly near the sources, the soils may be contaminated to the water table and below.

The “Addendum to the Revised Data Summary Report dated October 16, 2007 for the Koppers Inc facility in Gainesville, Florid”. (AMEC, March 16, 2010) present maps of both surface and subsurface soil data for dioxins, arsenic, PAHs (and Benzo(a)pyrene, and pentachlorophenol. It is from these figures that the areas of the site where the contamination primarily near the surface.

Note that these maps do not incorporate historical data, or concentrations reported in source area investigations.

The proposed plan identifies several other COCs for on-site soils, however, these are not on figures, and do not necessarily coincide with those identified in the risk assessment. In addition, no comparisons have been made to leachability criteria.

Proposed Remedy

Cleanup Criteria for direct contact commercial/industrial onsite. The preferred remedy proposes regrading and covering on most of the site, excavation of “some” contaminated soil in non-source areas.

  • Excavation of areas of contaminated soil in non-source areas on-site; consolidation of excavated soil to source areas to be capped
  • Establishment of a low-permeability cap/cover over all four source areas, including the consolidated soil excavated from non-source areas (on-site or off-site)
  • Surface grading and cap covers on approximately 83 of 86 acres on the Site property.
  • Institutional controls to mitigate risks from exposure to Site soil, sediment, surface water or groundwater.


Historical operations at the Koppers Superfund site have resulted in releases of airborne dust and vapors that have impacted the surrounding community. In the past, numerous complaints have been filed because of odors and dust.

The off-site soil investigations have shown that site-related chemicals in this soil, particularly dioxins, occur in elevated concentrations compared to normal concentrations from natural sources. This is the result of these chemicals being deposited on the soils over nearly 100 years of the Koppers wood-treating operations. Because the contaminated material in the soil has settled from the air, it is likely that most of the contamination remains near the surface. In addition, these contaminants have likely entered homes either directly or from the tracking of contaminated surface soil into the home.

In recent years, actions have been taken to reduce dust and air emissions, and currently the facility is closed. However, contaminants in the offsite soil still pose a hazard – both directly and by their ongoing potential to enter homes. Inhalation of contaminated soil and dust particles also remains a potential hazard.

So how does the cleanup of the Koppers site address the hazards of inhaling contaminants?

Superfund remedies are typically designed to eliminate current and ongoing risks identified during investigations and to prevent future risks. Risk-based soil cleanup levels are developed to be protective for persons contacting contaminants in soil via inhalation as well as ingestion and skin contact. Florida SCTLS, indentified as cleanup levels in the EPA proposed plan, should therefore be protective for inhaling dust particles.

This does not address historical exposures or chemicals that may remain in homes. The City and County Commissions have recommended that after defining wherever soil contamination above the cleanup levels is identified, the remedy should cover not only the soil cleanup but also dust removal within those homes that may be contaminated.

In addition to these actions, concerns remain about dust and contamination being spread during the cleanup process. To address this, a management plan to control dust and a plan to monitor emissions is required to be in place.

A list of EPA guidance documents related to air monitoring requirements can be found at the following website.

What can you do?

EPA’s Superfund remedy will not address all concerns raised by the community, particularly damages associated with historical exposures. Expressions of public anger about the historic lack of serious action to protect the community will increase the pressure for the present remedy and future actions to be rigorous.

In addition, the public comment period, which ends October 15, 2010, is also the time to express any concerns you may have about the cleanup of contaminated soils and house dust and about requirements for reducing the release of contamination from the site during the cleanup process.

Fugative dust

Have there been any air quality tests done at the Koppers site?

There haven’t been any air quality tests done at the Koppers Site and in surrounding neighborhoods.

However, in August 2009, a study “Potential Fugitive Dust Impact predicted from Air Dispersion Modeling” was conducted. A US EPA model was used to predict air quality impacts generated by fugitive dust caused by vehicle traffic at the Koppers site. Concentrations of different contaminants were predicted such as naphthalene, dioxin, arsenic and PAH. These concentrations were compared to EPA ambient screening levels. The report shows that predicted concentrations are below ambient screening levels and therefore there are no significant health risks from fugitive dust emissions at the Koppers site

Nevertheless, it is important to point out that these results have not been approved by the EPA and the FDEP because of technical reasons. Moreover, the model does not use current conditions because vehicle traffic is used as a generator of fugitive dust

Koppers Site Contaminants

The following discussion provides a brief summary of hazards associated with creosote -the primary waste material at the Koppers Site – and also the specific chemicals that have been identified as presenting the primary risks for contact with soils and groundwater.


There are multiple adverse health effects associated with creosote. Inhalation can result in irritation of the respiratory tract. Ingestion of large amounts of creosote can cause mouth and throat burning as well as stomach pains. Coal tar creosote is classified as a probable human carcinogen. Indeed, long-term exposure to creosote at low levels has been known to result in skin cancer and cancer of the scrotum.

The primary chemicals of concern within creosote compound —with harmful health effects—are polycyclic aromatic hydrocarbons (PAHs), phenols, and creosols. Of these three, PAHs (see information below) are the most common ingredient. Additional information on Creosote related to sources, fate and transport, exposure and adverse health effects can be found on the Agency for Toxic Substances and Disease Registry website:

Chemicals of Concern

The following chemicals were selected as chemicals of concern (COC) because they were detected at concentrations above health based criteria and therefore pose the greatest potential risk to human health.


Arsenic is a naturally occurring element that is widely present in the Earth’s crust. Inorganic arsenic is widely used in the wood treating industry as part of the Copper Chromated Arsenate solution. The toxicity of arsenic depends on its form with inorganic arsenic being much more toxic than organic arsenic. The two most dangerous effects of arsenic exposure for the general population are lung cancer from inhaling arsenic and skin cancer from swallowing it.

Additional information on Arsenic related to sources, fate and transport, exposure and adverse health effects can be found on the Agency for Toxic Substances and Disease Registry website:

The largest concentrations of arsenic were detected next to the former South Lagoon with concentrations greater than 1,000 mg/kg.  Off-site soil testing is currently being conducted. However, early results show concentrations that are above Florida residential standards adjacent to the Western side of the site.

Dioxins / furans:

Dioxin is thought to be one of the most toxic chemicals ever made by humans. Dioxins are present at the Koppers Site because of the use of pentachlorophenol and other chlorinated phenols. There are many contaminants that belong to this group with each contaminant having a different toxicity.
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is considered the most toxic contaminant belonging to this group.

In humans, TCDD are associated with many adverse health effects that include chloracne (a skin eruption resembling acne), headaches, dizziness, digestive disorders, and generalized aches and pains. Regarding carcinogenicity, the World Health Organization has classified dioxin as a human carcinogen. In the United States, dioxin may reasonably be anticipated to cause cancer.

TCDD are very persistent in the environment because their structure is resistant to chemical and biological degradation. Dioxins breakdown slowly with sunlight and they are stored in the environment within soils and sediments.

Dioxins / furans were detected throughout the Site at concentrations above the Florida default commercial/industrial SCTL.

TCDD-TEQ (Toxicity Equivalent) expresses the toxicity of a mixture of different dioxins as if all of them were TCDDs. The former process area was the only location throughout the site where TCDD-TEQ concentrations were above EPA default acceptable range for industrial / commercial soils.
Off-site sampling for dioxins is currently being conducted. However, early results have shown that dioxin concentrations adjacent to the western side of the site are greater than the Florida residential Soil Cleanup Target Levels (SCTLs). Samples taken 100 feet away from the western portion of the site are still above the Florida residential Soil Cleanup Target Levels (SCTLs).
Testing will continue to be done around the Site (South, North, East and West of the site).

Additional information on Dioxins related to sources, fate and transport, exposure and adverse health effects can be found on the Agency for Toxic Substances and Disease Registry website:

PAHs (Polycyclic Aromatic Hydrocarbons):

PAHs are a group of chemicals that are the dominant components in creosote.  These can include thousands of different chemicals. Of these chemicals, several of the higher molecular weight compounds are considered potentially carcinogenic.  Of these, Benzo(a)pyrene (BaP) is considered to be one of the more potent of these compounds. It has been identified as a probable human carcinogen because there is some evidence to suggest that it causes skin, lung, and bladder cancer in humans and in animals. Because a large number of these carcinogenic PAHs occur together, the additive effect of these is calculated -

Additional information on related to sources, fate and transport, exposure and adverse health effects can be found

Pentachlorophenol (PCP)

Pentachlorophenol is a synthetic substance that is made from other chemicals and was used as a wood preservative.

Regarding health effects, studies on workers have shown the exposure to pentachlorophenol causes a very high fever, profuse sweating, and difficulty breathing. This dangerous increase in body temperature can damage different organs and tissues and may also result in death. Moreover, long term exposure can cause a decrease in the immune function and liver damage. Animals studies have shown that exposure can result in damages of the thyroid and reproductive system.

Additional information on Pentachlorophenol related to sources, fate and transport, exposure and adverse health effects can be found on the ATSDR website:

Only 5 areas throughout the site had concentrations greater than the Florida Commercial/Industrial SCTLs: three sample locations in the former process area, one location at the former drip tracks, and one location at the former north lagoon.


Naphthalene is a low molecular weight PAH compound that is common in creosote and other petroleum products that may have been used at the Koppers Site.

Symptoms of acute exposure (short them exposure to high concentrations) include headache, nausea, vomiting, diarrhea, malaise, confusion, anemia, jaundice, convulsions, and coma. Long-term exposure to naphthalene through inhalation of vapors can cause cataracts and retinal hemorrhage. The EPA has classified naphthalene as a possible human carcinogen by inhalation. Some workers exposed to naphthalene by inhalation have developed laryngeal carcinomas or neoplasms. Additional information on Naphthalene related to sources, fate and transport, exposure and adverse health effects can be found on the ATSDR website:

Naphthalene has been a focus for evaluating impacts to groundwater at the Koppers Site.

What are the proposed clean up numbers for these chemicals in soil?

The proposed plan lists a number of additional chemicals of concern to be addressed during implementation of the remedy.

Florida Soil Cleanup Target Levels (SCTLs) include criteria that are protective for direct contact to the contaminants using either residential or commercial/industrial land use assumptions, and also to address the potential for the contaminants to be an ongoing source of contamination to groundwater (leachability criteria). These leachability criteria were not explicitly included in the Plan, but may be more conservative. The following table compares these values for the five primary COCs.

Florida Soil Cleanup Target Levels (mg/kg) for Primary COCs
Maximum Concentration detected Residential SCTL Commercial SCTL Groundwater Leachability Criteria
Arsenic 2.1 12 NA
TCDD-TEQ 0.000007 0.00003 0.003
BaP-TEQ 3.13 0.1 0.7 8
Naphthalene 55 300 1.2
Pentachlorophenol 7.2 28 0.03


Groundwater CTLs may be found at: