Former Hexagon Laboratories Site Management Plan

Executive Summary

This Site Management Plan outlines the comprehensive approach for managing the Former Hexagon Laboratories property, located at 347 Industrial Drive, spanning 15 acres of mixed industrial and natural landscape. The plan details environmental remediation strategies, ongoing monitoring protocols, and land use recommendations to ensure the long-term protection of human health and the environment while maximizing the site's potential for future development.

Since cessation of laboratory operations in 2018, the site has undergone extensive environmental assessment revealing contamination primarily in historical chemical storage areas. This plan addresses remediation of identified contaminants, establishes monitoring programs, and provides a framework for adaptive management responsive to changing conditions and new scientific understanding.

Site History

Hexagon Laboratories operated at this location from 1962 to 2018, conducting pharmaceutical research and chemical analysis. The facility comprised five main buildings, three smaller structures, and various above-ground tanks used for chemical storage. Laboratory operations involved the use of various organic compounds, heavy metals, and radioactive isotopes for research purposes.

Throughout its operational history, the facility was subject to varying regulatory standards, with documented environmental incidents occurring in 1978, 1989, and 2005. The most significant incident involved accidental release of trichloroethylene from an above-ground storage tank, which resulted in contamination of approximately 2 acres of soil and groundwater.

Environmental Assessment

Comprehensive environmental characterization conducted between 2019-2022 identified several areas of concern:

• Building 1: Elevated polychlorinated biphenyls (PCBs) in indoor air and surface dust
• Building 2: Mercury contamination in the former analytical chemistry laboratory
• North Tank Farm: Petroleum hydrocarbons and chlorinated solvents in soil and groundwater
• South Disposal Area: Elevated levels of lead, arsenic, and other heavy metals in surface soils
• East Wetland: Evidence of biological impacts consistent with chemical contamination

Groundwater monitoring revealed a plume of chlorinated volatile organic compounds (VOCs) extending approximately 800 feet to the northeast, approaching the property boundary but remaining on-site. Surface water testing of the adjacent creek indicated periodic exceedances of copper, nickel, and zinc during storm events.

Remediation Strategy

The selected remediation approach combines proven technologies with innovative solutions designed to minimize disruption to the surrounding environment while effectively reducing contaminant concentrations:

Soil Remediation

• Excavation and off-site disposal of highly contaminated soils in Building 2 and the South Disposal Area (estimated 2,500 cubic yards)
• In-situ chemical oxidation treatment for VOC-impacted soils in the North Tank Farm
• Soil vapor extraction system for areas with elevated VOC concentrations
• Capping of residual contamination in areas where remediation is technically impracticable

Groundwater Remediation

• Enhanced aerobic bioremediation using electron donor injection to accelerate natural attenuation
• Monitored natural attenuation with quarterly validation sampling
• Installation of a permeable reactive barrier (PRB) at the downgradient property boundary
• Groundwater circulation wells to enhance mixing and treatment effectiveness

Building Decontamination

• Asbestos abatement following regulatory requirements
• Mercury removal utilizing specialized vacuum and amalgamation techniques
• Chemical cleaning of surfaces with PCB contamination
• Hvac system cleaning or replacement as dictated by sampling results

Long-Term Monitoring Plan

Long-term monitoring will continue for a minimum of 10 years following completion of remedial activities, with periodic reviews to assess progress and determine if any modifications to the approach are needed:

• Groundwater monitoring in a network of 25 wells on a quarterly schedule
• Semi-annual surface water sampling at creek locations downstream of the site
• Annual sediment sampling in the adjacent creek and east wetland
• Soil vapor monitoring on a quarterly basis for the first 3 years, then semi-annually
• Ecological monitoring of vegetation in the east wetland area

A comprehensive site review will be conducted annually by the Site Management Team, with formal reports submitted to the regulatory agencies and made available to stakeholders. All monitoring data will be maintained in a centralized electronic database with appropriate security measures.

Institutional Controls

To ensure protection of human health and the environment, the following institutional controls will be implemented:

• Environmental covenant restricting land use to appropriate activities commensurate with the level of remediation
• Notification requirements for property transfer or major development activities
• Groundwater use prohibition within the affected area
• Access restrictions for remaining capped areas
• Soil disturbance limitations in areas of residual contamination

Community Engagement

Effective community engagement is central to successful site management. The following measures will be implemented to maintain transparency, gather stakeholder input, and provide information:

• Dedicated website with project information, progress reports, and monitoring data
• Bi-annual community meetings with rotating locations throughout the affected area
• Establishment of a Community Advisory Committee representing diverse stakeholder interests
• Regular communication with local elected officials and government agencies
• Distribution of quarterly newsletters to area residents and businesses

Budget and Implementation Timeline

Estimated costs for the Site Management Plan activities over the 15-year planning horizon total $14.5 million, allocated as follows:

• Remediation implementation: $8.2 million
• Long-term monitoring: $4.5 million
• Administration and reporting: $1.2 million
• Contingency: $600,000

Major milestones include completion of remediation activities by Year 3, attainment of groundwater cleanup standards by Year 7, and transition to a more limited monitoring program by Year 10.

Health and Safety

All site activities will be conducted in accordance with applicable health and safety regulations. A comprehensive Health and Safety Plan will be maintained and updated throughout implementation. This includes:

• Personal protective equipment requirements for all site personnel
• Specific protocols for handling identified contaminants
• Regular safety training and briefings
• Emergency response procedures tailored to site-specific hazards
• Regular safety audits to identify and address potential hazards

Future Use Considerations

Upon successful completion of remediation activities, the site will be evaluated for appropriate future use based on the level of cleanup achieved and community input. Potential future uses may include:

• Light industrial or commercial development compatible with the established institutional controls
• Environmental research and educational facilities
• Green infrastructure and stormwater management improvements
• Limited recreational use in areas achieving residential-level cleanup standards
• Habitat restoration in the east wetland area

Any future development will be subject to regulatory approval and will incorporate environmental monitoring and mitigation measures as appropriate.

Conclusion

This Site Management Plan provides a comprehensive framework for addressing contamination at the Former Hexagon Laboratories site while balancing environmental protection with future land use considerations. Through diligent implementation of remediation activities, consistent monitoring, and ongoing stakeholder engagement, the site can be transformed from a liability into an asset that contributes to the economic and environmental well-being of the community.

The success of this plan depends on the collaborative efforts of regulatory agencies, responsible parties, technical consultants, and community stakeholders. Regular assessment of plan effectiveness and adaptation to new information or conditions will ensure that environmental protection remains the primary priority throughout the site management process.