An investigation launched by North Dakota State Geologist Ed Murphy has found "levels of exposure to erionite [a zeolite mineral with characteristics similar to asbestos] in North Dakota are the same as in some of the Turkish villages ravaged by mesothelioma" according to a report in Nature.
"The North Dakota study eventually grew into a global collaboration including cancer biologists, geologists, epidemiologists, environmental scientists and physicians." Results were presented earlier this month at the Chicago Multidisciplinary Symposium in Thoracic Oncology. [right, photomicrograph of an erionite fibre in road gravel from North Dakota. Credit, K. Eylands/UND EERC in Nature News]
"North Dakota doesn't seem to have a higher incidence of the disease than is normal nationwide," but it may take 30 years or more for effects to appear, so studies are underway on construction and quarry workers who may have had extended exposure to erionite dust used in road construction.