Former Western Minerals Company Plant Denver, Colorado
Site Background
The former Western Minerals Products Company plant at 111 South Navajo Street in Denver, Colorado, began operating sometime prior to 1967. The plant operated until 1990, processing vermiculite mined in Libby, Montana. This vermiculite was contaminated with asbestos.
The facility exfoliated ("popped" or expanded) vermiculite to manufacture insulation and other products. Over 100,000 tons of vermiculite were processed at the Denver site.
Since 1990, the site has been occupied by Minnesota Corn Processors, a corn syrup manufacturer. The land around it is used primarily for light industry, with a community baseball field to the southeast. The nearest homes are approximately one-quarter mile away. According to the U.S. Census, almost 13,000 people lived within one mile of the site in 1990.
Recent EPA soil sampling at the site showed some Libby asbestos in several areas. Much of the site, however, is covered by buildings and an asphalt parking area. Adjacent properties, including the baseball field, were free of asbestos contamination. Asbestos was not detected in any of the air samples collected.
Conclusions and Recommendations
Former Workers
Conclusion: Former Western Minerals plant workers were exposed to hazardous levels of Libby asbestos. People who lived with former workers were also probably exposed to hazardous levels from fibers carried home on workers' hair and clothing.
Recommendation: Identify former workers and their household contacts (people who lived with them) to evaluate potential health effects.
Current Workers
Conclusion: Limited areas at the site contain Libby asbestos in the soil and could pose a health hazard. Most areas are free of contamination, however, and currently people are not frequently in the contaminated areas. Future exposures remain possible if construction or other activities disturb the soil beneath the asphalt parking lot.
Recommendation: Clean up soil that contains Libby asbestos and develop a plan to prevent future exposures.
Past Community
Conclusion: Not enough information is available to determine whether people who lived near the plant were exposed to hazardous levels of Libby asbestos. However, community exposures were probably minor, especially compared to those for former worker exposures, and are unlikely to lead to adverse health effects.
Recommendation: Review new information that becomes available to determine appropriate actions to protect public health.
Present Community
Conclusion: Community exposure to remaining Libby asbestos onsite is currently minimal and does not appear to pose a health hazard. Currently not enough data are available to determine whether people are being exposed to Libby asbestos from waste that may have been used in the community. In other communities, vermiculite waste has been used for a variety of purposes, such as fill, driveway surfacing, and 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.
