A communication transmitted from Yi-An Huang, City Manager, relative to Awaiting Report Item Number 24-69 regarding asbestos concerns with the MBTA's Alewife construction

January 29, 2025 To the Honorable, the City Council: In response to Awaiting Report 24-069, dated December 9, 2024, city staff from the Community Development Department, the Department of Public Works and the Public Health Department have provided the update below on the MBTA’s Red Line Hi-Rail Access Tunnel Project and on- going coordination with the MBTA. Red Line Hi-Rail Access Tunnel Project – Background The Massachusetts Bay Transportation Authority (MBTA) is planning to construct an access tunnel in the Alewife area to allow hi-rail work vehicles access to the Red Line Tunnel. Currently, the closest access for these critical maintenance vehicles is at Charles/MGH station. The new Hi-Rail Access Tunnel will enable shorter and less frequent Red Line shutdowns, faster commutes, and support the MBTA’s continued efforts to bring the subway system to a state of good repair. The MBTA is currently in design of the $32.9M project, with construction anticipated to start in June 2026 and finish in March 2028. Red Line Hi-Rail Access Tunnel Project – State Environmental Review Process The project site was used for manufacturing between 1919 and 1983, and is known to have contaminated soil, including asbestos. Based on this history, the MBTA is managing the construction and handling of contaminated soils under the Massachusetts Department of Environmental Protection (MassDEP) regulations, including a Release Abatement Measure (RAM) Plan and a Non-Traditional Asbestos Abatement Work Plan (NTAAWP). In order to identify the extent and type of contamination in the soils, the MBTA completed 64 soil borings on a 15’ grid and analyzed 148 soil samples.

The testing identified asbestos fibers in 56 of 148 samples (37%). Of those 56 samples containing asbestos fibers, 46 samples contained less than 1% asbestos and the highest was 1.92%. The asbestos fibers were identified in the top 6’ of soil, correlating with fill material. Based on these samples, the RAM Plan is proposing to treat all of the top 6’ of material as asbestos contaminated. The soil testing also identified areas with naphthalene contamination, consistent with historic uses on the property. The two slides below are from the MBTA’s September 29, 2024 community meeting and highlight the areas that will be treated as containing asbestos (top 6’ of soil), the area with naphthalene contamination, and summaries of the Excavation Plan and the RAM Plan.

The draft RAM plan for the excavation was released in August 2024. The MBTA had discussions with local residents and the Alewife Study Group in September and October, and hosted a public meeting on September 29, 2024. The comment period on the draft RAM plan closed on December 8, 2024. While the MBTA has not committed to following the Cambridge Asbestos Protection Ordinance, Chapter 8.61, which was passed in 1999 due to concerns that the MassDEP oversight of soil handling activities around asbestos contaminated soils was lacking and additional local measures needed to be put in place to properly protect the community. Since that time, MassDEP has increased their oversight and is currently completing a study of release sites containing asbestos following the increased protocols. MassDEP has indicated to city staff that the study results show that there were no recorded off-site releases based on substantial perimeter monitoring data above any applicable threshold in any site so managed. In addition to the increased MassDEP oversight, the MBTA have proposed several protocols that surpass MassDEP requirements including a tighter testing grid, additional air monitoring locations, and lower limits for the air monitoring. The MBTA have also indicated that they are continuing to evaluate the use of tents with filtration or full tenting and venting, as the design and bidding process progresses. Status of MBTA Design and Coordination with City Staff To further advocate that the MBTA comply with the Cambridge Asbestos Ordinance and incorporate tenting and venting protocols, as requested in the Council Order, city staff met with the MBTA and their consultants. The MBTA indicated that their tunnel plans are currently at 75%-design, so further changes are feasible before a final plan for construction and remediation is submitted. They also indicated that they may not be able to commit to a final decision on

tenting and venting until the project is bid and the final RAM plan is submitted to MassDEP towards the end of 2025 or early in 2026. Staff emphasized that there is significant public interest in understanding what they intend to do before the full bidding and regulatory timelines play out. City staff will continue to meet with the MBTA for updates on their plans and procedures for construction, including the request to follow the Asbestos Ordinance, and monitor the RAM Plan process with DEP. Very truly yours, Yi-An Huang City Manager