DTC provided environmental consulting services in support of the complete demolition and reconstruction of the Helene Grant Head Start School.
Environmental services included:
- Phase I Environmental Site Assessment (ESA)
- Combined Phase II & III ESA (Expedited Site Assessment)
- Hazardous building material surveys for:
- Asbestos, lead-based paint (LBP), & Universal Wastes
- Polychlorinated biphenyls (PCBs)
- Preparation of a Remedial Action Plan (RAP)
- Preparation of a PCB Building Materials Abatement Plan
- Preparation of contract plans & specifications for:
- Site remediation (contaminated soil / fill material),
- Abatement of hazardous building materials, &
- Sub-slab radon mitigation system.
- On-site supervision of remedial actions & abatement
- Preparation of a final Remedial Action Report (RAR)
In October 2012, DTC completed a Phase I ESA, which identified five on-site Areas of Environmental Concern (AOCs) and one off-site AOC. Two rounds of soil and one round of groundwater testing were completed that found site-wide contaminated urban fill material as the only significant environmental concern.
To significantly reduce remediation costs, DTC developed a RAP that proposed construction of a site-wide “cap” to render the contaminated fill material “inaccessible” to future human contact. Per the CT Remediation Standard Regulations, contaminated fill material will be placed below the proposed building and parking / landscaped areas. The proposed cap will allow all existing contaminated fill material to remain on-site, without the need for off-site disposal.
Hazardous building material surveys were completed as part of the pre-demolition due diligence. Testing for the potential presence of PCBs was a major component of the surveys. While testing is not required by regulation, the Owner elected to test for PCBs to eliminate potential delays and cost increases during demolition.
Initial testing indicated the presence of elevated levels of PCBs in caulk within the building. In coordination with the Environmental Protection Agency (EPA), the City of New Haven Board of Education (BOE) instructed DTC to conduct indoor air testing to evaluate the potential for exposure to airborne PCBs. Testing revealed PCBs at levels exceeding the EPA indoor air health guidelines for schools. As such, the BOE decided to relocate students to an alternative facility. DTC assisted school personnel with developing decontamination procedures for books, furniture, & equipment to minimize the potential for transporting PCBs to the new location.
Once the students were relocated, the BOE and DTC held a public information session, during which DTC presented the PCB testing results and answered questions from the audience. DTC also prepared an informational brochure that was provided to parents and staff.
Comprehensive sampling throughout the main portion of the building (constructed in 1965) identified PCBs above regulatory limits in a wide variety of interior and exterior building materials, including multiple types of caulk, window glaze, wall & ceiling paint, vinyl floor tile & mastics, roofing materials, moisture barriers, glues, etc.
Evaluation of multiple abatement scenarios concluded that the most cost effective and timely option included selective removal and disposal of materials with PCBs ≥50 ppm, and then demolition and disposal of the remainder of the 34,400 square foot, one-story, building as PCB waste (<50 ppm).
In accordance with the Federal Toxic Substance Control Act (TSCA), demolishing the building in this manner did not trigger a requirement to submit a plan to EPA for review and approval, avoiding a potential 6 to 8 month delay in the demolition schedule.