Federal regulations require mines and other industrial workplaces periodically to measure fibers in the air, using a small pump and collector attached to the worker’s chest.īut the rules only require measurement of long, thin fibers Cook was convinced shorter fibers could also be toxic. Nobody had observed anything like that before.”Ĭook told anyone who would listen that the standard way of defining these fibers couldn’t explain what was really happening. “They were breaking off, and the dose was increasing. “We could see some particles were splitting,” said Cook in an interview years later. Studying microscopic images of the rats’ lungs, he realized that some of the mineral particles were actually multiplying. He combined advanced microscopic examination of fibers with dosage studies in rats, introducing as many as a billion fibers into rats’ lungs in an effort to simulate long-term exposure.

‘Nobody had observed anything like that before’Ĭook was a chemist with an incisive mind, deep curiosity, and gritty determination. He invented new methods of isolating and counting the microscopic fragments, and created novel ways of testing more materials faster. But Cook’s work suggests that investigators and the government have been using the wrong techniques to find it. Several studies failed to pinpoint a cause of the mesothelioma. Minnesota taconite workers have long worried about the fibers, because they get mesothelioma – a rare cancer that attacks the lining of the lung – at twice the expected rate. Minerals that break into tiny fragments, often mixed with other types, are found in rocks around the world, including on the Iron Ranges of Minnesota and Wisconsin. But others took it up, and his week, for the first time, that work will finally be presented at a symposium on elongated mineral particles in Duluth. It was a landmark case, an early flexing of government muscle to protect natural resources from industrial pollution.įor one of the scientists at the EPA lab, Philip Cook, it was also the beginning of a lifelong quest to figure out whether the slivers were really asbestos, and if not, what they were and whether they could also be harmful to human health.Ĭook died before he could finish his work. After a long court battle, Reserve was forced to build a disposal pond inland. The mineral fragments were traced 50 miles up the shore to Silver Bay, where the Reserve Mining Company’s taconite processing plant was dumping thousands of tons of waste rock into the lake. Families lined up at fire stations to get bottled drinking water, and the city rushed to build a filtration plant, which continues to operate today.

It’s been known since ancient times that asbestos is harmful to human lungs, so the discovery caused panic in the community. But in the late 1960s, scientists at the Environmental Protection Agency lab in Duluth looked through a microscope at a sample of Duluth’s water and saw tiny, thin mineral fragments that looked suspiciously like asbestos. For many years, the cold, clear water of Lake Superior was pure enough to serve unfiltered as the water supply for cities along the North Shore.

Phil cook pump