Former W.R. Grace/Zonolite Company Site Beltsville, Maryland
Site Background
The former W.R. Grace/Zonolite Company site at 12340 Conway Road in Beltsville, Maryland, operated from 1966 until the early 1990s. The plant processed vermiculite mined in Libby, Montana. This vermiculite was contaminated with asbestos.
The facility exfoliated ("popped" or expanded) vermiculite to manufacture insulation, building products, agricultural products, and fireproofing material (brand name: Monokote). Records from 1966 through 1988 indicate that over 93,000 tons of vermiculite were processed at this site.
Since 1998, Atlantic Transportation Equipment, Ltd. (ATEL) has leased the property. This company operates a truck maintenance and repair shop out of the former vermiculite processing building. Land use immediately surrounding the site is primarily industrial. The closest residential area is approximately one-half mile away from the site. According to U.S. Census data, 320 people lived within one mile of the site in 1990.
Recent EPA soil tests detected no residual Libby asbestos in on-site soils, and most of the site is covered with structures or gravel. A low level of residual Libby asbestos was detected at one location inside the facility, but no asbestos fibers were found in the air sample collected inside the former processing building.
Conclusions and Recommendations
Former Workers
Conclusion: People who worked at the W.R. Grace/Zonolite facility were exposed to hazardous levels of asbestos. People who lived with former workers were probably also exposed to hazardous levels from fibers carried home on workers' hair, skin, and clothing.
Recommendation: Identify former workers and their household contacts (people who lived with them) to evaluate potential health effects.
Current Workers
Conclusion: Currently, the site poses no apparent public health hazard from asbestos. Although trace levels of Libby asbestos were detected in an isolated area inside the facility, that area is not accessible to workers. Future disturbances or renovation of the area, however, could result in hazardous exposures.
Recommendation: Eliminate the possibility of exposure to the contaminated area inside the facility.
Past Community
Conclusion: Although ATSDR continues to review information, currently not enough data are available to determine whether people who lived near the plant were exposed to hazardous levels of Libby asbestos.
Recommendation: Review new information that becomes available to determine appropriate actions to protect public health.
Present Community
Conclusion: Community exposure to Libby asbestos from plant emissions or from onsite asbestos-contaminated materials poses no public health hazard. Currently not enough data are available to determine whether individuals are being exposed to Libby asbestos from waste that may have been used for a variety of purposes, such as fill, driveway surfacing, or soil amendments.
Recommendation: Review new information that becomes available to determine appropriate actions to protect public health.
Consumer Products
ATSDR did not evaluate products that contain Libby vermiculite, such as vermiculite attic insulation, as part of this project. Information concerning vermiculite consumer products is available on ATSDR's Web site at www.atsdr.cdc.gov/NEWS/vermiculite051603.html and on EPA's Web site at www.epa.gov/asbestos/insulation.html.
