On 9/22/14, MDCH filed an NRC Report (# 1096105), indicating that a furnace repair technician had identified a mercury spill from a switch on the furnace while completing a service call. The County Health Department screened the site with a Lumex, and reported ambient mercury levels of up to 50,000 (nanograms per cubic meter) ng/m3 near the furnace and 34,000 ng/m3 in the basement. After opening windows and ventilating the house, levels were generally reduced to less than 1,000 ng/m3. MDCH and the County Health Department requested EPA assistance to address the situation.

The health effects of mercury are detailed by the ATSDR as follows:

The nervous system is very sensitive to all forms of mercury. Exposure to high levels of metallic, inorganic, or organic mercury can permanently damage the brain, kidneys, and developing fetus. Effects on brain functioning may result in irritability, shyness, tremors, changes in vision or hearing, and memory problems. Short-term exposure to high levels of metallic mercury vapors may cause effects including lung damage, nausea, vomiting, diarrhea, increases in blood pressure or heart rate, skin rashes, and eye irritation.

EPA mobilized to the site at approximately 5:00 PM on 9/22/14 and met with the County Health Department representative, and later with the homeowner.  The homeowner requested that we return the next morning to conduct monitoring and cleanup work. The homeowner planned to stay in the home overnight, with the windows open to maintain ventilation. EPA and START arrived on site at 8:00 AM on 9/23/14. The team closed windows and screened all rooms in the house with the Lumex. Mercury vapor concentrations were below the acceptable concentrations for most sensitive people  (less than 1,000 ng/m3) in the breathing zone in all areas of the house except right near the furnace. Mercury vapors were roughly 2,000 ng/m3 there. Visible beads of mercury were present in the furnace. As these conditions presented an imminent and substantial endangerment to public health, welfare, or the environment, ERRS was mobilized and a removal action was initiated at the site. 

2.1.1 Narrative

Planned response activities on-site include:

a)      Assessing the site;

b)         Securing, staging characterizing spilled mercury and mercury contaminated waste;

c)     Consolidating and packaging all materials containing hazardous substances, pollutants and contaminants for transportation and off-site disposal; and

d)      Transporting and disposing of all characterized or identified hazardous substances, pollutants, wastes, or contaminants that pose a substantial threat of release at a Resource Conservation and Recovery Act/CERCLA-approved disposal facility in accordance with  EPA’s Off-site Rule (40 C.F.R. § 300.440).

2.1.2 Response Actions to Date
9/23/14
ERRS mobilized to the site on 9/23. The laundry room area (that contains the furnace) was isolated from the rest of the house with poly sheeting and tape. Porous materials within the room were bagged for screening. A mercury vacuum was used to remove most visible mercury beads from the furnace. Some beads could not be accessed readily - work will continue on this effort tomorrow. The floor of the laundry room was inspected, and visible beads were removed from flooring, from behind molding and from under the hot water heater. Surfaces were cleaned with DI water. A ventilation system was set up in the laundry to vent the room overnight. EPA monitoring has not identified elevated mercury in other areas of the house to date - however investigation in ongoing.

9/24/14
Remediation activities continued within the laundry room (identified point source) to confirm the absence or presence of elemental mercury, mercury vapors and mercury impacted materials.  Mercury vapor surveys also continued on the main level of the property.  

EPA activities concentrated on the removal of visible mercury beads embedded within the metal tapered seams of the furnace.  Removal activities included the disassembly of furnace components in order to access areas where mercury beads could be removed, utilization of mercury HEPA vacuum, ventilation of main work area, application of deionized rinse water to impacted furnace, and internal furnace components.  Unfortunately, after extensive work to recover mercury beads from within the furnace, mercury vapors being emitted from the furnace still exceeded 4,000 ng/m3. Therefore, rather than continue costly recovery efforts within the furnace further, the OSC decided to remove the contaminated furnace and replace it.  

Bagged clothes and personal items were allowed to heat up in the sun, then screened. Most bags were found to be contaminated (per criteria below). Contents with low levels of contamination removed from bags and allowed to air out prior to re-bagging and screening. 

Cleanup operations for the day concluded with the furnace/laundry room being sealed off from the rest of the second level basement with poly vinyl sheeting and placing a portable heater and ventilation blower within the room.  

No other areas of contamination have been identified within the residence.

Over the day and at the end of the day mercury vapor levels were surveyed periodically throughout the house (windows open). Vapor levels did not exceed 1,000 ng/m3.

9/25/14

Today, team efforts focused on removing the contaminated furnace and packaging and staging it for disposal. After removal of the furnace and thorough cleaning of the furnace footprint area, mercury vapors averaged about 200 ng/m3 in the furnace footprint area and about 400 ng/m3 in the breathing zone of the laundry room. These results indicate that the laundry room is now safe for occupancy by sensitive persons (per criteria detailed below). The ploy sheeting isolating this room from the rest of the house was removed.

Bagged clothes and personal items with low levels of contamination were again allowed to heat up in the sun, then screened. All but one bag were still found to be contaminated. All contaminated personal items were inventoried and photographed and staged for disposal as mercury contaminated debris.

All mercury and mercury contaminated waste was collected and staged for proper disposal.

Over the day and at the end of the day mercury vapor levels were surveyed periodically throughout the house (windows open). Vapor levels did not exceed 1,000 ng/m3.


Mercury Action Levels
According to the Agency for Toxic Substances and Disease Registry (ATSDR) and the Michigan Department of Community Health, a residential structure is safe for occupancy by sensitive persons when mercury levels are below 1,000 nanograms/cubic meter (ng/m³), in the breathing zone. On this response, the site will be considered cleaned up at this site when the visible mercury has been removed, and mercury levels in the breathing zone are less than 1,000 ng/m^3. Both of these goals were achieved on 9/25/14.

For screening objects, and debris, ATSDR recommends that objects with mercury levels above 10,000 ng/m³ be disposed of outright. Objects with mercury levels between 10,000 and 6,000 ng/m^3 may aired out to reduce levels, and objects with mercury levels below 6,000 ng/m^3 may be kept. At this site, debris that was suspected to be contaminated with mercury was bagged and mercury levels within the bags was measured. If the mercury level of the bagged debris exceeded 6,000 ng/m^3, and level did not reduce after airing out, the debris was disposed of outright as mercury contaminated debris. 

2.1.3 Enforcement Activities, Identity of Potentially Responsible Parties (PRPs)
Investigation into potentially responsible parties is ongoing.

* The above accounting of expenditures is an estimate based on figures known to the OSC at the time this report was written. The OSC does not necessarily receive specific figures on final payments made to any contractor(s). Other financial data which the OSC must rely upon may not be entirely up-to-date. The cost accounting provided in this report does not necessarily represent an exact monetary figure which the government may include in any claim for cost recovery.