This study investigated asbestos-related lung disease and deaths in Northeast Minneapolis due to asbestos exposure from a vermiculite processing plant that operated from 1938 to 1989.

Vermiculite ore from a mine in Libby, Montana was contaminated with naturally occurring asbestos. For over 50 years, Western Mineral Products (later called the W. R. Grace plant) in Northeast Minneapolis used this contaminated ore. For many years, waste material was given freely to the community, and used as fill in driveways, yards, and gardens. The vermiculite waste contained up to 10% asbestos. As a result, asbestos contamination became widespread in the neighborhood around the plant, at 1720 NE Madison St., Minneapolis, Minn. (see map).

In a previous study, Minnesota Department of Health (MDH) interviewed a group of over 6,000 community members willing to participate in later health studies, and found several ways that people throughout the neighborhood were exposed to asbestos. People were exposed from playing on waste piles as children, or from directly handling the waste. Air modeling showed that residential areas closest to the plant were likely to have higher concentrations of asbestos fibers in the air compared to background levels.

In 2012, the University of Minnesota reported the results of a respiratory health study of the community. Chest x-rays of community members were examined, looking for unusual changes in the lining of the lungs, called pleural abnormalities. Pleural abnormalities are not an indicator of disease, but they are evidence of exposure to asbestos. This confirmed with clinical evidence that community members with a history of direct contact with waste or living in close proximity to the plant for many years were exposed to harmful levels of asbestos fibers.

Community Health Study: Methods

The 2013-2014 Northeast Minneapolis Community Vermiculite Health Study assessed asbestos-related cancer incidence and death to determine if there was more asbestos-related disease than expected, based on the general Minnesota population. This health follow-up included all members of the community and worker/household study participants who were known or reported to be alive in 1988 and who gave written consent for further study (5,848 study participants).

Cancer cases were identified by matching information about study participants collected during the interview with records in the Minnesota cancer registry from 1988-2010, focusing on asbestos exposure-related cancers: lung and mesothelioma. Death records in Minnesota and from the National Death Index also were matched to participants and identified the cause of deaths occurring between 1988 and 2011.

Community Health Study: Results

The findings suggest that past exposure to asbestos from the vermiculite processing plant may have affected the health of people living and working in the area at the time.

The number of mesothelioma cancers were greater than expected in women, which suggests that asbestos exposure was not limited to occupational exposure. The levels of exposure to asbestos in the community may have contributed to the development of disease.

Lung cancer incidence was elevated in both men and women. This may be due to high smoking rates that were reported in the study group.

There were more deaths from lung cancer and mesothelioma in women than expected based on the state rates.

More information about vermiculite in Minneapolis:
Alexander, B. et al. (2012). Radiographic Evidence of Nonoccupational Asbestos Exposure from Processing Libby Vermiculite in Minneapolis, Minnesota. Environmental Health Perspective, 120(1), 44-49. (PDF)

Tests Show No Health Threat from 'Libby' Asbestos (PDF), January 2012

Kelly, J. et al. (2006). Community Exposure to Asbestos from a Vermiculite Exfoliation Plant in NE Minneapolis. PubMed. Contact Tess Konen at tess.konen@state.mn.us.

Vermiculite Processing in Northeast Minneapolis

Information about current exposure from the vermiculite insulation product in homes is available from the Environmental Protection Agency and on our website at Vermiculite Insulation.

For questions, contact Minnesota Biomonitoring at health.biomonitoring@state.mn.us or 1-800-205-4987 (651-201-5900)