Mesothelioma and Asbestos Exposure
It was the Conference on the Biological Effects of Asbestos at the New York Academy of Sciences, organized by Irving Selikoff in November 1964 , that put both mesothelioma and asbestos on the map. Before that meeting, few people in the scientific or general community had much knowledge of either subject.
There they learned the nature and numerous essential industrial uses of a group of naturally occurring mineral fibers, collectively known as asbestos, although in fact comprising at least five distinct materials, chemically, physically, and geologically. Of these, chrysotile, a serpentine mineral mined mainly in Quebec and the Ural mountains of Russia, made up over 90%.
Of the remainder the two most important were crocidolite and amosite, produced mainly in South Africa and Australia, both amphibole minerals with distinctive qualities valuable for heat insulation, naval marine use, and the production of large-bore cement pipes.
Two other amphibole mineral fibers were anthophyllite, of limited production in Finland, and tremolite, little used, though by far the most widespread geologically.
Presenters at the conference stated that within some 20 years of the first industrial exploitation of asbestos in the 1880s, workers heavily exposed to airborne fiber and dust developed a distinctive, seriously disabling and sometimes fatal diffuse pulmonary fibrosis, later termed asbestosis.
Little was done to limit exposure until the late 1930s, when after a well-conducted survey of four asbestos textile plants in North Carolina, Dreessen et al (2) and others of the U.S. Public Health Service recommended in 1938 that a workplace dust concentration of 5 million particles per cubic foot (about 15 fibers/mL) should not be exceeded.
Mainly because of the Second World War, this recommendation was not implemented; and probably for the same reason it went unnoticed that there were case reports by some German pathologists of malignant tumors of the pleura and peritoneum in men with asbestosis. Thus it was only in the 1950s that the causal association of asbestos exposure with lung cancer in the United Kingdom, and later with mesothelioma in South Africa , was recognized.
It was the Conference on the Biological Effects of Asbestos at the New York Academy of Sciences, organized by Irving Selikoff in November 1964 , that put both mesothelioma and asbestos on the map. Before that meeting, few people in the scientific or general community had much knowledge of either subject.
There they learned the nature and numerous essential industrial uses of a group of naturally occurring mineral fibers, collectively known as asbestos, although in fact comprising at least five distinct materials, chemically, physically, and geologically. Of these, chrysotile, a serpentine mineral mined mainly in Quebec and the Ural mountains of Russia, made up over 90%.
Of the remainder the two most important were crocidolite and amosite, produced mainly in South Africa and Australia, both amphibole minerals with distinctive qualities valuable for heat insulation, naval marine use, and the production of large-bore cement pipes.
Two other amphibole mineral fibers were anthophyllite, of limited production in Finland, and tremolite, little used, though by far the most widespread geologically.
Presenters at the conference stated that within some 20 years of the first industrial exploitation of asbestos in the 1880s, workers heavily exposed to airborne fiber and dust developed a distinctive, seriously disabling and sometimes fatal diffuse pulmonary fibrosis, later termed asbestosis.
Little was done to limit exposure until the late 1930s, when after a well-conducted survey of four asbestos textile plants in North Carolina, Dreessen et al (2) and others of the U.S. Public Health Service recommended in 1938 that a workplace dust concentration of 5 million particles per cubic foot (about 15 fibers/mL) should not be exceeded.
Mainly because of the Second World War, this recommendation was not implemented; and probably for the same reason it went unnoticed that there were case reports by some German pathologists of malignant tumors of the pleura and peritoneum in men with asbestosis. Thus it was only in the 1950s that the causal association of asbestos exposure with lung cancer in the United Kingdom, and later with mesothelioma in South Africa , was recognized.
Until that time even the very existence of primary malignancies of the mesotheleum was questioned by reputable pathologists. Looking back, however, a review by Saccone and Coblenz in 1943 had included the identification of over 40 cases in autopsies published since 1870, and referred to two cases of “endothelioma” reported in 1767 by Lieutaud in France among 3000 autopsies.
That mesothelial cancers in low frequency probably occurred well before the industrial use of asbestos is discussed more fully later. Indeed, a low background incidence of unknown etiology has almost certainly continued, affecting both children and adults.
Mesothelioma and Asbestos Exposure
That mesothelial cancers in low frequency probably occurred well before the industrial use of asbestos is discussed more fully later. Indeed, a low background incidence of unknown etiology has almost certainly continued, affecting both children and adults.
Mesothelioma and Asbestos Exposure