The Dartmouth Department of Environmental Health and Safety (EHS) recently completed an independent assessment of Wilder Hall to better understand the potential exposures to elemental mercury, and its vapors, related to historical laboratory use.
The results confirm that Wilder Hall is safe for normal daily activities, and no conditions were identified that would be expected to pose a health or safety risk to building occupants.
The assessment by the environmental health consulting firm, Gradient, was completed on Dec. 10, 2025, and is attached to this memo, along with an FAQ on mercury and its presence in Wilder Hall for faculty, staff, and students. Below you will find additional relevant background information and a summary of the assessment’s findings.
Given the proximity to winter break, EHS will schedule and host Q&A sessions early in January 2026 to provide additional context and answer questions. If you have immediate questions, please contact Annette Chism at ehs@dartmouth.edu.
Background and findings
Wilder Hall has housed the Physics and Astronomy Department since its construction in the late 1800s. Historically, elemental (liquid) mercury was commonly used in physics laboratories and was also present in items such as fluorescent light bulbs and thermostats. Small amounts of mercury spilled decades ago can remain absorbed in porous building materials, such as flooring or walls, where it may slowly release mercury vapor.
Dartmouth has been aware of this legacy issue for more than 25 years and has taken ongoing, appropriate steps to ensure the safety of building occupants.
More recently, in September 2025, EHS engaged Woodard and Curran, Inc. (W&C), an independent environmental consultant, to conduct additional air monitoring throughout Wilder Hall. W&C, through a subcontractor Environmental Health Inc. (EHI), assessed every room within Wilder Hall using specialized monitoring equipment, and they collected a total of 529 mercury vapor readings. These readings were taken under normal building conditions—without disturbing floors or walls—to reflect typical occupancy and use. Separately, in November 2025, W&C conducted additional tests under destruction repair and renovation scenarios. These tests simulate construction activities such as removing flooring, drilling into walls, etc.
In December 2025, Gradient assessed the data and report from W&C and confirmed that the mercury in the building does not pose a health risk during normal daily activities, including for sensitive subgroups such as a pregnant person. Additionally, under a destructive repair/renovation scenario, Gradient confirmed that potential mercury exposure in Wilder Hall is unlikely to pose an adverse health risk to workers.
Still, as an added precaution, EHS is updating protocols for Wilder Hall to support and ensure safe and consistent practices during maintenance, repair, and renovation work. Moving forward, EHS must be consulted prior to conducting any work that would disturb building materials in Wilder Hall. This includes minor projects, such as hanging objects on walls, and major repairs and renovations.
During repairs and renovations, Dartmouth contracts with an environmental consultant to develop a work plan that addresses work means and materials and requires personal protective equipment. Dartmouth may also work with environmental consultants to develop a work plan for more minor work in the building.
Attachments:
FAQ - More Information Regarding Mercury Vapors in Wilder Hall