IDEM: Explanation of Significant Differences

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Governor Mitch Daniels

IDEM > Environmental Cleanup > Federal Programs > Explanation of Significant Differences Explanation of Significant Differences

As a result of information collected during the remedial design and views expressed by the community, IDEM has determined that it is appropriate to make significant changes to the remedy which was incorporated into the Continental Steel Superfund Site 1998 Final Record of Decision (ROD) as amended in 2003. The Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) Section 117(c) and the National Contingency Plan (NCP) 300.435(c)(2)(i), require that if any remedial action taken differs in any significant respect from the final plan, the President or the State shall publish an explanation of the significant differences and the reasons such changes were made.

Site Name and Location

The Continental Steel Superfund Site (CSSS) is located on West Markland Avenue in the City of Kokomo. The site is approximately 183 acres in size and consists of an abandoned steel manufacturing facility (Main Plant), pickling liquor treatment lagoons (Lagoon Area), a former waste disposal area (Markland Avenue Quarry), and a former waste disposal and slag processing area (Slag Processing Area).

This aerial photo of CSSS shows locations of the four source areas.

Administrative Record File

This Explanation of Significant Differences (ESD) will become part of the administrative record file for the CSSS. The Administrative Record can be viewed at the Kokomo/Howard County Public Library, Genealogy Section, 220 North Union Street, Kokomo, and at the IDEM Central File Room on the 12th Floor, Indiana Government Center North Building, 100 North Senate, Indianapolis, from 8:15 a.m. until 4:45 p.m.

What's Different

Solids will not be consolidated on site. Soil cover will be placed over closed lagoons and surrounding area. Shallow groundwater will be extracted using wells.

Acid Lagoon Area 1998 Remedy

RCRA surface impoundment closure
Excavate contaminated solids and consolidate on site in CAMU* →
Collect and contain shallow groundwater with expanded interception trench system and dispose off site →
Deed & groundwater use restrictions

*(Note: A CAMU is a Corrective Action Management Unit, often a landfill, that is allowed under the Resource Conservation and Recovery Act (RCRA) to consolidate large areas of waste into a smaller area. The CAMU that was to be constructed at Continental Steel was a landfill.)

Wildcat and Kokomo Creeks 1998 Remedy

What's Different

Creek solids (PCB and VOC solids) will be disposed off site at an existing permitted facility.

Excavate PCB solids (sediment and bank soil) along Kokomo Creek and dispose on site in CAMU →
Install common soil cover
Collect & contain shallow groundwater and dispose off site
Elevated VOC solids removal and on site disposal →
Deed and groundwater use restrictions

Markland Quarry 1998 Remedy

What's Different

Quarry sediment will be disposed off site at an existing permitted facility.

Cover contaminated solids with common soil
Dispose of Quarry sediment in Lagoon Area CAMU →
Contain & collect shallow groundwater & dispose at Waste Water Treatment Plant
Excavate contaminated sediment from Quarry Pond
Backfill Quarry Pond with alternative fill material
Deed and groundwater use restrictions

The basis for the remedy changes above, is that RCRA Hazardous and Toxic Substances Control Act (TSCA) waste from other areas of the site will not be disposed in the Lagoon Area.

About 2% of the CAMU contents would have been sediment from the creeks and Markland Quarry. These are expected to be RCRA hazardous (due to the level of Volatile Organic Compounds [VOCs]) or TSCA wastes (containing over 50 parts per million PCBs). For this reason, the CAMU needed to meet stringent RCRA and TSCA requirements.

The other 98% would have been non-hazardous contaminated soil and sludge from the 56-acre acid lagoon area. These wastes may be contained and covered in place without construction of a landfill. RCRA has different closure requirements for non-hazardous surface impoundments. With the change, the surface impoundments will be closed to meet the RCRA requirements. However since a CAMU will not be built, the lagoon contents will not provide a base for a CAMU. The lagoons will not be consolidated, so the grade will be level and the land will be more useful. A cover will be placed over the entire area, similar to the Main Plant, Markland Quarry and the Slag Area.

Reasons and Expected Outcome

An earlier start to the creeks construction can be achieved. Under the previous on site disposal approach it would have been necessary to spend the first year constructing the CAMU base. Eliminating on site disposal allows U.S. EPA to do work in Wildcat and Kokomo creeks first, providing an earlier reduction in risk.
Reduces the cost of the remedy by approximately $20 million. Cost was a major factor in the original choice against off site disposal. Also, off-site disposal was undesirable due to risks posed by transporting roughly 630,000 cubic yards of contaminated material. Closure of the lagoons in place eliminates the need to transport 98 percent of the waste material. The material in the lagoons and drying beds, while contaminated, is not hazardous.
Provides equivalent protection in the long term. According to the results of data that was collected in this area, contaminants are not leaching to the groundwater. Off site disposal of the smaller volume of hazardous and TSCA waste (sediment from Wildcat and Kokomo creeks and from the Markland Avenue Quarry) provides equal protection of human health, with less short term risk.
Off site disposal of hazardous and TSCA material is more acceptable to the community. The community has voiced opposition to constructing a hazardous waste landfill in Kokomo.
Land reuse potential in the Acid Lagoon Area would improve. The landfill cap would have required protection. The rules for construction in the flood plain required that the remaining acreage would be compensatory flood storage area. Future construction would not have been allowable. Since hazardous and TSCA material will not be disposed here, there will not be a need to build a landfill with an impermeable cap or a flood water storage area.
U.S. EPA will likely provide a limited amount of money each year. The on site landfill would have required about $40 million in the first year. Remedial action can begin earlier by implementing these changes because they reduce the initial construction cost.
The purpose of the trench system was to collect VOC contaminated groundwater. Data collected in 2001 did not detect VOCs in the lagoon area shallow groundwater above Maximum Contaminant Levels (MCLs). Therefore, the trench system is not needed.

Main Plant 1998 Remedy

What's Different

Elevated VOC solids will be treated in place using Heated Soil Vapor Extraction.

Excavate PCB Solids along Kokomo Creek and dispose on site.
Install common soil cover
Collect & contain shallow groundwater, dispose off site
Elevated VOC solids removal and on site disposal in CAMU →
Deed and groundwater use restrictions

Reasons and Expected Outcomes

IDEM and U.S. EPA agreed to spend the 10 percent of the cost of the remedial action that must be provided by the State before U.S. EPA has fully funded the remedial actions. Since the State will perform the Main Plant work before the Lagoon Area work is conducted by U.S. EPA, the CAMU would not be available for disposal of excavated solids from the Main Plant. Disposing of these materials off site allows work to begin and end earlier.
Heated Soil Vapor Extraction (HSVE) in the VOC contaminated area of the Main Plant would be more effective and simpler to implement than excavation. Excavation near and possibly underneath Park Avenue would be difficult and expensive. During the remedial design, IDEM and U.S. EPA determined that HSVE is well suited for the removal of VOCs from soils with high clay content. HSVE was therefore included in the designs for the Main Plant VOC contaminated soil. The change meets the criteria for reduction of toxicity, mobility and volume through treatment and does not increase the cost of the remedy. As a result of this change, contaminants will be removed instead of being contained in a landfill on site.