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This health consultation summarizes the air monitoring that was conducted at the former Johns Manville Property Site in Nashua, New Hampshire in support of the EPA removal action that occurred between September 1996-June 1997. Specifically, this health consultation evaluates air sampling data relative to the potential release of asbestos fibers to the surrounding community during the demolition of the two site buildings and the removal of asbestos-containing material (ACM) from the site during the removal action. This health consultation is being prepared by the New Hampshire Office of Health Management, Bureau of Health Risk Assessment (OHM) through a combined cooperative agreement with the Agency For Toxic Substances and Disease Registry (ATSDR).


Site Location and Demographics

The former Johns Manville Property Site is located in a heavily populated section of the City of Nashua at 40 Bridge Street and 10 Sanders Street (Figure 1). The site comprised approximately four acres and contained two vacant manufacturing buildings: the main production building located at 40 Bridge Street (Building 40), and the tile finishing building (Building 10) located at 10 Sanders. The site is bordered to the north by the Nashua River, to the east by other industrial properties, to the south by Bridge Street, and to the west by railroad tracks owned by Guilford Rail Systems (formerly Boston & Maine Railroad). The site is located on Bridge Street; Sanders Street is a small street situated between the two buildings (1).

The estimated population residing within a one-mile radius of the site is approximately 13,000 people (3). The area surrounding the site is comprised of predominantly light industrial and low income housing. Located within this area are 13 schools, including day care facilities, one hospital, and 13 housing units (elderly, low income, and halfway homes). There is an area of low income housing located to the west of the site and there is a development containing approximately 60 units and 200 residents some 200 feet north of the Nashua River (1).

Site History

The Johns Manville Company began conducting operations at this location in 1900. The company combined asbestos fibers and cement to produce a number of asbestos plate products for commercial and industrial use. The company generated large amounts of waste materials, consisting of quality rejects, sludge, baghouse dust materials, and other sheet materials, as part of its production process. The company disposed of this waste material on site and also distributed it as free fill material to local property owners in Nashua and surrounding communities. This practice continued for a number of years until the early 1970s, when it was discontinued as a result of federal regulations concerning the use of asbestos containing materials. The Johns Manville Company ceased production of asbestos containing products at the 40 Bridge Street location in December 1985 and sold this facility, as well as other properties in this area, to a local developer in December 1987. The new site owner leased the facility to a separate manufacturing firm that produced non-asbestos insulation products until June 1990. Manufacturing operations ceased at the facility at that time and manufacturing equipment was dismantled and removed from the site buildings. The property has changed ownership several times in recent years, although the site buildings have not been used for manufacturing purposes since 1990 (1).

Federal, State, and City Involvement

The city of Nashua, the state of New Hampshire, and EPA have had significant involvement with the former Johns Manville Property Site since manufacturing activities ceased in 1990. Concern for trespassers entering the site and for the deteriorated conditions of the two site buildings led the city of Nashua, in November 1994, to install an eight-foot perimeter security fence around the site to restrict access to the facility. Following the release of a consultants' report to the city, which documented the deteriorated condition of the structures, the presence of large quantities of ACM within the buildings and concluded that the condition of the structures constituted a threat to public safety (3), the city condemned the buildings and ordered their demolition and removal in April 1995. In November 1995, the city of Nashua asked OHM to determine whether the large quantities of asbestos and the continuing deterioration of the site buildings constituted a health threat to the community. At the city's request, OHM specifically evaluated the health risk posed by the potential release of asbestos fibers from Buildings 40 and 10 in the event of a natural disaster (major fire or building collapse). OHM, in conjunction with ATSDR, released a health consultation dated February 29, 1996, which concluded that the former Johns Manville Property site constituted a public health hazard and recommended that the two site buildings be demolished and all ACM be removed in a controlled manner that would not cause the release of asbestos to the surrounding community (4).

EPA Removal Action

Based on the public health and safety concerns of the state and city, the EPA committed to a removal action to demolish the two abandoned site buildings and to remove the asbestos-containing demolition debris from the site. Once EPA committed to this course of action, the focus of public health concern shifted from the potential uncontrolled release of asbestos during a fire or building collapse to dismantling the site buildings and disposing of the asbestos-containing wastes in a manner that would not cause a release of asbestos to the surrounding community.

Prior to the initiation of the removal action in September 1996, EPA put together a task force of state and local stakeholders to provide EPA with input to the proposed removal action. The task force was comprised of EPA and its contractors; the New Hampshire Department of Environmental Services (DES); OHM; ATSDR; The City of Nashua; and the Johns Manville Neighborhood Task Force Group (local citizens' group). The task force, which met weekly onsite, initially worked to develop a plan that would ensure the demolition of the site structures with minimal adverse impacts to the surrounding community. Because the presence of large quantities of ACM within the structural elements of both deteriorated buildings posed a serious problem relative to its removal, the task force's first objective was to develop a plan that would allow for the demolition of the site buildings and the safe removal of ACM without causing a release of asbestos to the surrounding community. Taking advantage of structural conditions that related to the original design of the buildings, EPA's contractor (OHM Remediation Services Corp.) proposed a method that provided for the demolition of the structures on a section-by-section basis utilizing: 1) selective cutting and removal of key structural elements (piping systems, beams, etc.) during the predemolition phase, 2) controlled and predictable dismantling of consecutive 16 ft. x 28 ft. wall and roof sections, and 3) managing debris piles until disposal. The plan specified the need for constant dust control using water suppression (misting) during the demolition phase and either water suppression or tarping of asbestos wastes until it could be removed from the site (5).

Actual demolition activities at the site began September 3, 1996, with the test removal of a portion of Building 10. After the task force evaluated this test demolition and determined it to be successful, the removal action continued with the total demolition and removal of asbestos-containing demolition debris from Building 10, being completed by September 26, 1996 (6). The focus of the removal action then shifted to Building 40 in October 1996, with the total demolition of this structure and removal of asbestos-containing demolition debris being completed by the following spring. Concurrent with the demolition of these two site structures, large quantities of ACM were uncovered and removed from beneath the building foundations. Fill material was brought in to the site and the entire area was graded during the final phase of the project. The removal action concluded on June 28, 1997.

Air Monitoring Activities

As previously stated, once EPA made the decision to conduct a removal action, public health concern shifted to the actual demolition of the site buildings and the disposal of asbestos-containing demolition debris in a manner that would not result in the release of asbestos to the surrounding community. EPA's on-scene coordinator asked the EPA Environmental Response Team (ERT) of Edison, NJ, to develop an air monitoring plan that would assist the task force in evaluating any potential off-site releases of asbestos fibers during demolition activities.

This health consultation will not provide a technical discussion of the air monitoring plan that ERT developed for the site, but will discuss aspects of the air monitoring as it relates to the evaluation of potential airborne releases of asbestos fibers from the site during the removal action. The air monitoring plans for the site are contained in the following documents,"Johns Manville Manufacturing Site, Nashua, NH, Air Sampling Plan (8/96)," "Johns Manville Manufacturing Site, Nashua, NH Building No. 10 Air Sampling Plan (9/96)" and "Johns Manville Manufacturing Plant Site Asbestos Air Monitoring/Sampling Standard Operating Procedures (revision date 2/17/97)," which ERT prepared.

ERT's plan provided for air sampling to be conducted to identify ambient fiber/asbestos levels in areas of demolition work activity within the site buildings and outside of the site perimeter. Samples were analyzed by Phase Contrast Microscopy (PCM) in accordance with approved OSHA or NIOSH analytical procedures, with additional analysis being performed by Transmission Electron Microscopy (TEM) utilizing NIOSH Method 7402 (7). TEM analysis was utilized during the early phases of the project and periodically throughout the course of the removal action as a quality control check and for comparison with the PCM method results. Air samples were collected on 25-mm diameter cassettes containing a mixed cellulose ester filter (MCEF) with pore size 0.45- 0.80 um equipped with an electrically conductive 50-mm extension cowl. The cassettes were connected to Gillian personal sampling pumps set at 1.5-2.0 liters/minute (L/min) for area sampling, and to Gillian Aircon sampling pumps operating at 7-8 L/min for perimeter monitoring. In addition to this equipment, two fixed Real-Time Aerosol Monitoring (RAM) units with data loggers and a third mobile RAM without a data logger were used to monitor dust levels at the site during periods of heavy site activity and to provide real-time data for comparison with the other collection media.

Air sampling at the site was performed at a number of area and perimeter monitoring stations, the daily location and number of these stations being determined by EPA with input from other task force members. Factors affecting the configuration and placement of air monitoring stations included the nature and duration of work activity, location of work activity within the site, proximity of work activity to the nearest human receptors in the adjacent community, and meteorological conditions. Area monitoring consisted of a minimum of one ambient station and three on-site stations located within areas of high dust potential during demolition activities. Perimeter monitoring consisted of a minimum of eight off-site monitoring stations located north, east, south, and west of the site. The majority of perimeter monitoring stations, on any particular day, were located downwind of site activities and were placed to record any potential airborne releases of asbestos fibers that might enter inhabited areas. Associated with the perimeter monitoring, a meteorological station was set up to collect weather data during site activities. With respect to the two stationary RAM units, RAMs were placed upwind and downwind of the site, while the third RAM unit was used as a mobile station to be moved periodically throughout the day to locations downwind of heavy work activity (8).

Prior to the start-up of demolition activities, EPA and other task force members established a protocol for evaluating the air sampling data collected during the removal action. The protocol provided for air samples from area and perimeter air monitoring stations to be taken on a daily basis when demolition activities occurred and for the samples to be collected and analyzed overnight by EPA's contract lab for the project. Analytical results for the samples would then be forwarded, before the start of the next work day, to the EPA OSC who would promptly disseminate the data to OHM, DES, and the City Health Department for review. OHM and DES shared the primary responsibility for reviewing the air sampling data relative to concentrations of asbestos fibers in ambient air and for notifying EPA if the amount of asbestos in the air approached a level of public health concern. Should the concentration of asbestos fibers in ambient air become elevated, EPA would suspend or modify demolition activities at the site until such time as EPA, in consultation with other Task Force members, became convinced that the airborne asbestos fiber concentrations had decreased and no longer posed a health risk to the community.

To assist in this evaluation, EPA requested that ATSDR collaborate on an action level for asbestos fibers in the air that could be used during this removal action. ATSDR concurred that a site perimeter action level of 0.01 fibers/cc would be protective of community residents during the period of building demolition and ACM removal at the site. In addition, ATSDR concurred with an action level for particulate matter of 150 ug/cm above background, not to exceed 300 ug/cm for a 5-minute period to be used for the evaluation of data collected by the RAMs (9).

ERT performed limited pre-demolition air monitoring at the site during August, 1996 to gather meteorological data and to establish background levels of asbestos fibers in ambient air. Perimeter monitoring stations detected airborne asbestos levels in the range 0.001 -0.003 fibers/cc during this time.

Routine air monitoring at the site commenced with the start of the demolition of Building 10 on September 3, 1996. Air monitoring was performed daily at the site, depending on the type of activity and weather conditions existing during that particular day. The total number of area and perimeter monitoring stations (besides the RAM stations) in daily use at the site normally ranged between 10-20 stations, although during periods of severe weather (especially winter) and towards the end of the removal action, when the majority of the demolition and removal work had been completed, the number of air sampling stations was reduced or eliminated. During the course of the entire removal action (September 1996-June 1997), there were approximately 90 days when air monitoring was conducted in conjunction with demolition or removal activities.

Between September, 1996 and June, 1997 a total of 1324 air samples were collected at the site in support of the removal action (10 ). Asbestos fiber concentrations in ambient air collected at perimeter air monitoring stations were in the range 0.001- 0.008 fibers/cc with the average concentration close to the detection limit of 0.001 fibers/cc. A review of area air monitoring station data revealed, on average, somewhat higher concentrations of asbestos fibers than the perimeter monitoring station data. These area air sampling stations were located within the site exclusion zone adjacent to areas of heavy work activity that the general public could not access. Comparisons of perimeter air sampling data with the related area air sampling data revealed substantially lower levels of asbestos fibers at the perimeter stations, with no exceedances of the perimeter action level of 0.01 fibers/cc observed.

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