The site is a residential property located in Lutherville, Maryland, a northern suburb of Baltimore. The site consists of a single house and its associated property. The property is located within a residential neighborhood.
MDE responded to the property on December 20th, and based upon air quality readings and the visible presence of mercury requested that the family evacuate the home. Elemental mercury contamination was observed by MDE personnel in the basement and on the ground floor.
The magnitude of the spill is estimated at approximately 1 1/2 pounds onto a hard floor (porous, non-friable asbestos tile). Mercury was also observed on the hardwood steps and flooring of the ground level floor. Additionally, Mercury was observed on and around the furnace, which was located in the immediate proximity to the spill. MDE conducted a gross cleanup of the visible mercury, but was not able to remove all of it due to its distribution throughout the basement and into the cracks of the floors.
On Thursday, February 12, 2009, EPA On Scene Coordinator Ham and START mobilized to the Site and met with MDE and the homeowner. START conducted air monitoring using a Lumex mercury vapor analyzer. Concentrations up to 10,000 ng/m3 were detected in the basement of the residence. Mercury vapor was also detected at elevated levels in the kitchen of the home. Beads of elemental mercury were also visibly present in the area around the furnace, in cracks in both rooms of the basement floor, and on the steps leading up to the first floor. Trace levels of mercury vapor were identified in the remaining areas of the house. Undoubtedly, if the heat were turned up to normal levels, these vapor levels would be much higher. Based on these readings and observations, the OSC issued a Special Bulletin on February 12, 2009 authorizing cleanup of the mercury. EPA, START, and an EPA cleanup contractor mobilized to the site on February 17, 2009, to begin the cleanup of the site.
The downstairs family room and utility room were vacuumed using a mercury HEPA vacuum. Mercury beads were identified throughout the utility room during vacuum operations.
MercX solution was applied to the kitchen, downstairs family room, and utility room floors and allowed to set over the weekend. Residual material was mopped up and contained in a poly drum for disposal. A second coat of MercX solution is currently being applied to the downstairs family room and utility room.
Furniture and items on the floor in the utility room were bagged and kept in a conex box which was heated to approximately 70 - 80 degrees Fahrenheit. Items were screened using the Lumex 915+. Any bag with a resulting concentration of less than 1,000 nanograms per cubic meter was segregated to be returned to the home. Any bags or items identified with concentrations greater than 1,000 nanograms per cubic meter of mercury will be heated and ventilated prior to a secondary screening.
The house is not currently being heated above 50 degrees Fahrenheit to minimize spread of mercury vapors throughout the house. The furnace is located in the downstairs utility room. Once this room has been vacuumed, heating and venting of the home may occur.
The upstairs rooms and hallway were isolated from the rest of the house by poly sheeting. Rooms were vented on Tuesday, February 24 and heated with space heaters overnight. The home heating system was not used during this time. The upstairs rooms and hallway were screened with the Lumex 915+ the morning of Wednesday, February 25. Readings were all less than 200 nanograms per meter cubed at both four feet above the floor and one foot above the floor.
A public fact sheet is being prepared for distribution to the surrounding residential properties. The fact sheet will also be posted on this website in the documents section.
Vacuuming and treatment with Merc-X solution will continue in the downstairs family room and utility room as necessary, along with bagging and screening of any items.
Items that are screened above 1,000 nanograms per cubic meter of mercury will be allowed to vent and rescreened individually.
The vacuuming and MercX application process may be repeated if needed, based on the vapor concentrations in specific areas of the house.
Confirmation air monitoring using the Lumex 915+ will occur in all areas of the home prior to final clearance via NIOSH analytical method 6009.
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