International Symposium on the Health Hazard Evaluation of Fibrous Particles Associated with Taconite and the Adjacent Duluth Complex
March 30 - April 1, 2003
History of asbestos-related issues in Minnesota
1972 - 1980: A federal lawsuit is filed against Reserve Mining Company over the disposal of taconite tailings into Lake Superior, leading to a trial lasting from April 1973 to April 1974. In June 1973, federal researchers indicate the tailings contain asbestos-like fibers. After many appeals on both sides, Reserve begins on-land disposal of tailings in March 1980 and improves air pollution controls at the Silver Bay facility. Several North Shore communities build water treatment plants. Read more (Download the PDF File)...
Purpose of International Symposium:
Minnesotans have been interested in the issue of mineral fibers in taconite ore - particularly from the eastern end of the Iron Range - since the Reserve Mining Case in the 1970s highlighted the presence of "asbsestiform minerals" in that ore body. Since then, numerous studies have been conducted on the ore, as well as people who work in the mining industry; however, due to a number of reasons including study limitations and lack of current scientific data, many significant questions remain unanswered. Read more (Download the PDF File)...
Charles W. Axten
St. Paul, Minnesota
Raleigh, North Carolina
Jeffrey L. Myers
Robert P. Nolan
New York, New York
Scientific and Organizing Secretariat
Robert P. Nolan
International Environmental Research Foundation
P.O. Box 3459, Grand Central Station
New York, NY 10163-3459
Tel: (800) 927-5822
Fax: (800) 709-0028
This International Symposium will be convened to assess the current state of knowledge concerning any health hazards, which might be associated with the ingestion and inhalation of fibrous particles produced from the processing of taconite ore.
Concern about fibrous particles in taconite arose from their similarities to fibers of amphibole asbestos minerals, which are known to be human carcinogens. The mineralogical characteristics of asbestos fibers will be reviewed and compared with the fibrous particles known to be present in taconite ore from the eastern end of the Iron Range. The epidemiological and experimental animal studies for asbestos-related disease (including gastrointestinal cancer from asbestos in drinking water) will be evaluated and compared to those of the fibrous minerals in the taconite. The focus will be on the amphiboles in the cummingtonite-grunerite and tremolite-ferroactinolite series and other fibrous particles in both the Iron Range and Duluth Complex. This will include examination of the reported occurrences of any asbestiform ferroactinolite, crocidolite asbestos, chrysotile asbestos, etc. In addition, an effort will be made to provide a scientific framework to address fibrous minerals which may be associated with non-ferrous mineral deposits in the rock of the Duluth Complex.
State-of-the-art risk assessment models for asbestos will be presented for developing worst-case and reasonably realistic scenarios for the fibrous particles associated with taconite and possibly the Duluth Complex. Risk assessment scenarios will be developed for environmental exposure levels related to the operation of the Silver Bay taconite processing facility and the use of taconite as aggregate. After a review and analysis of the information presented at the Symposium the Minnesota Department of Health intends to conduct a Risk Assessment for exposure to the types of fibrous particles found in taconite and possibly the Duluth Complex.
Questions to be Addressed by the Scientific Program of the Symposium
1. The concern about the microscopic fibrous particles in taconite originated from what observations? Are they still valid? What do we actually know about the health hazards of the fibrous particles including cleavage fragments that might result from processing taconite?
2. What are the physico-chemical properties of the fibrous particles in taconite ore, including crocidolite asbestos and asbestiform ferroactinolite, which indicate a potential for health hazard?
3. How do typical concentrations of airborne and waterborne fibrous particles - determined by state-of-the-art analytical transmission electron microscopy methods - found in the area surrounding the taconite processing plant in Silver Bay compare with background levels reported for asbestos around the world? What do we know about the importance of fiber length - is there any new evidence regarding the length of fibers and toxicity? What are the data required for determining if taconite waste rock and coarse tailings from the eastern end of the Iron Range can be used off-site? What considerations about fibrous minerals, if any, should be given in the development of non-ferrous mineral deposits in the Duluth Complex rocks?
4. What do the experimental animal studies reveal about the differences between the inhalation/injection/ingestion of asbestos and other fibrous mineral particles?
5. Do studies in human populations tell us anything about the potential health hazards, which might occur from exposure to fibers similar to those found in taconite?
6. What are the views held by the various Federal Regulatory Agencies (OSHA/EPA/MSHA/CPSC) regarding the distinction between asbestos and the fibrous particles associated with taconite? What is the importance of asbestos fiber type (mineral species), morphology, biopersistence and surface properties?
7. Using available risk assessment models for asbestos exposure, what are the lung cancer and mesothelioma risks associated with the environmental taconite exposures? What can be said about non-cancer risk of asbestos-related disease?
8. What is the scientific evidence that bears on the question that amphibole-bearing taconite from the eastern most end of the Biwabik Iron Formation, if used as aggregate, would pose a public health concern different from other widely used aggregate sources? How would one go about doing a risk assessment for the use of taconite waste rock as aggregate? Is there sufficient information available to perform a risk assessment for the use of this taconite waste rock as aggregate?
9. What science, if any, has developed since 1976, which might have influenced the Reserve Mining decision? Is it consistent with the scientific information available earlier or does it suggest some changes should be made?
10. Will new taconite production processes such as the direct reduced iron process (DRI) have any effect on the ambient fiber levels in Silver Bay?
Publication of the Workshop
The twenty-four papers will be prepared prior to or soon after the Symposium. After the presentations, the papers will be sent out for peer review before publication. The speakers will be required to submit their papers prior to the Symposium to allow the monograph to be published in a timely manner.
We are proposing to include edited accounts of the Panel Discussions, Questions Period, six Rapporteur's reports (one summarizing each Session) and an Introduction and Summary for the Symposium. The details of the Symposium's published form will be reviewed by the Scientific Committee when the program is finalized.
Three-Day International Symposium on Health Hazard Evaluation of Fibrous Particles Associated with Taconite and Adjacent Duluth Complex
Session I: Origin of the Problem
Chair: Prof. Arthur M. Langer
Rapporteur: Malcom Ross
9:15AM - 9:30AM
Ann Glumac and Tom Reagan
9:30AM - 10:00AM
Paper 1 - Geology of the Biwabik Iron Formation and Duluth Complex.
James D. Miller, Jr. and Mark A. Jirsa
10:00AM - 10:30AM
Paper 2 - Overview of the Mineralogy of the Mesabi Iron Range and the Duluth Complex.
Peter L. McSwiggen and G.B. Morey
10:30AM - 10:45AM
10:45AM - 11:15AM
Paper 3 - Definitions of Asbestos Minerals.
RP Nolan and Malcom Ross
11:15AM - 11:45AM
Paper 4 - Reserve Mining and the Asbestos Case.
William Brice and Michael Berndt
11:45AM - 12:15AM
12:15AM - 1:30PM
Characterization of the Fibrous Minerals
Chair: Richard J. Lee
Rapporteur: Prof. Arthur M. Langer
1:30PM - 2:00PM
Paper 1 - The Search for Fibrous Minerals within the Peter Mitchell Taconite Mine, Babbitt, Minnesota.
Malcolm Ross, R.P. Nolan and Gordon L. Nord
2:00PM - 2:20PM
Paper 2 - Characterization of Fibrous Particles by Analytical Transmission Electron Microscopy.
Gordon L. Nord and Richard J. Lee
2:20PM - 2:40PM
Paper 3 - Analysis of Airborne and Waterborne Particles Around a Taconite Ore Processing Facility.
Charles W. Axten and David Foster (MDH)
2:40 PM - 3:10 PM
3:10 PM - 3:30 PM
Exposure to Grunerite (Amosite) Asbestos:
Historical Perspectives of the Health Effects
Chair: Jeffrey L. Myers
Rapporteur: Graham Gibbs
3:30 PM - 4:00 PM
Paper 1 - Health Effects of Amosite Mining and Milling in South Africa.
4:00 PM - 4:30 PM
Paper 2 - Human Health Effects Associated with the Commercial Use of Grunerite (Amosite) Asbestos: Paterson, NJ - Uxbridge, United Kingdom.
4:30 PM - 5:00 PM
Paper 3 - Asbestos-Related Disease at Conwed, Cloquet, MN
Alan P. Bender and Allan N. Williams
5:00 PM - 5:30 PM
Grunerite (Amosite) Asbestos and Tremolite-Ferroactinolite Asbestos:
Risk of Environmental Mesothelioma
Chair: Joseph Ribak
Rapporteur: Geoffrey Berry and John F. Gamble
9:00 AM - 9:20 AM
Paper 1 - South African Experience with Asbestos-Related Environmental Mesothelioma: Is Asbestos Fiber Type Important?
9:20 AM - 9:50 AM
Paper 2 - Asbestos Exposure and Health Risks: Libby, Montana.
9:50 AM - 10:20 AM
Paper 3 - Environmental Mesothelioma Associated with Fibrous Tremolite: Lessons from The Experience in Turkey, Greece, Corsica, New Caledonia and Cyprus (Erionite should be mentioned).
Stavros H. Constantopoulos (to be presented by Joseph Ribak)
10:20AM - 10:40AM
10:40AM - 11:00AM
Paper 4 - Non-Occupational Exposure Issues: Libby, Montana.
Christopher P. Weis and Aubrey K. Miller
11:00AM - 11:20AM
Paper 5 - Evidence for Occupational & Environmental Exposure to Asbestos from a Vermiculite Exfoliation Plant in NE Minneapolis.
James Kelly, J. Johnson, L. Souther, D. Durkin, Tannie Eshenauer and Rita Messing and G. Pratt
11:20AM - 11:45AM
Paper 6 - Investigation of Exposures to Commercial Asbestos in Northeastern Minnesota Iron Miners who Developed Mesothelioma.
Wendy Brunner, Allan N. Williams, and Alan P. Bender
11:45AM - 12:00PM
12:00PM - 1:15PM
Experimental Animal and Epidemiology Studies of Asbestos
and Non-Asbestos Tremolite Including Ingestion Studies
Chair: Charles W. Axten
Rapporteur: Malcolm Ross
1:15PM - 1:45PM
Paper 1 - Experimental Studies of Asbestos and Non-Asbestos Tremolite.
1:45PM - 2:15PM
Paper 2 - Relative Potencies of Mineral Fibers in vivo: Ferroactinolite from Taconite.
Philip M. Cook, Lalita D. Palikar and David E. Coffin
2:15PM - 2:45PM
Paper 3 - Mechanisms of Fiber Carcinogens.
Agnes B. Kane
2:45PM - 3:15PM
Paper 4 - Ingestion Studies of Asbestos and Non-Asbestos Particles in Experimental Animals to Evaluate Carcinogenic Potential.
Ernest E. McConnell
3:15PM - 3:45PM
Paper 5 - Risk of Gastrointestinal Cancer from Inhalation and Injestion of Amphibole Asbestos.
3:45PM - 4:00PM
4:00PM - 4:45PM
Panel Discussion: Members TBN
Risk Assessment of Asbestos and Fibrous Mineral Particulates
Chair: A.M. Langer and Geoffrey Berry
Rapporteur: R.P. Nolan
8:30AM - 9:00PM
Paper 1 - Regulatory Overview of Asbestos and Other Fibrous Mineral Particulates. (CPSC/EPA/MSHA/OSHA)
Prof. A.M. Langer
9:00AM - 9:45AM
Paper 2 - State-of-the-Art Asbestos Risk Assessment: An Up-Date to 2002.
Geoffrey Berry and Graham Gibbs
9:45AM - 10:40AM
10:40AM - 11:00AM
11:00AM - 11:45AM
11:45AM - 12:35PM
Paper 3 - Risk Assessment from Human Exposure to Fibrous Particulates in Taconite Ore Due to Environmental Exposures and Those Associated with the Use of Aggregate Waste Rock.
Prof. Richard Wilson, R.P. Nolan and Charles W. Axten
12:35PM - 1:35PM