On July 10, EPA Region 8 received a
report of a mercury release via the National Response Center (NRC). The report
stated that approximately 20 milliliters of mercury was found on the floor
of the Mayflower Mill located two miles northeast of Silverton, Colorado. The
Mayflower Mill is a National Historic Landmark with daily self-guided tours
operated by the San Juan County Historical Society. The source of the mercury is undetermined. Upon discovery of the mercury, the San Juan County
Historical Society closed public access and secured the area. On Monday, June 13, two EPA On-Scene Coordinators mobilized to
Silverton with START and ERRs support to assess the mercury and determine further actions.
The response team conducted removal actions to address liquid mercury contamination and associated mercury vapor hazards in the basement of the former mill building. The team first established a contamination-reduction zone and safety controls to protect personnel and prevent spread. Free liquid mercury and contaminated dust and small debris were recovered using a mercury vacuum. After bulk removal, the team mopped and applied a mercury-neutralizing solution to reduce volatilization and suppress vapors. They also caulked cracks and other crevices near the spill area to limit vapors from hard-to-reach areas
