Document ZBavz4De4MmoarbBjXgoLpKOO

I I practice exposure of fire minutes to one part per million parts of air is intolerable. Hygiene control consists .preferably of local exhaust ventila tion or air dilution by general ventilation. Asbestos - Bxjake principally concerned here. The; inhalation of asbestos dust produces a condition known as asbestosls. j Asb'estos is the only important silicate apart from talc and oioa which does not oontain free silica and yet can cause disability and death. If the dust is kept below 5 million particles per cubic foot of air no cases pf asbestosls.are known to oocur. Ip Braksblok, beoause of the excellent dust collecting systems, dust counts-have never been found to be high. Beryllium - National Bearing Division affected. It is' only in recent years that this metal was recognized, as an Indus trial, hazard. In 1945, 170 eases of illness occurred in certain Ohio beryllium plants. Pive of these people died. Many cases have been reported from [other areas which have been sufficiently authenticated. One oan conclude that beryllium is very toxic even though the Satlqpal Institute of Health bulletin-No.181 published in 1945 indicated that there is no specific toxic action attributable to the beryllium ion. i Thane are two manifestations of beryllium poisoning; The acute pulmonary disease similar to pneumonia and a delayed chemical pneumonitis nop usually called pulmonary granulomatosis. Host! of the cases reported in the literature occurred in the fluorescent lamp manufacturing industry where the exposure was to beryllium phosphors; but six oases of typical pulmonary disease due to %the metal frerej reported from one plant engaged in casting a 5 beryllium copper* Four pf these six cases died. Beryllium copper oastings manu factured today! oontain about 0,30 beryllium and to date no hazard with this alloy .hap been demonstrated. i Prom| the data presently available, it appears that only a few persons are 'susceptible to chronio berylliosis and that mere traces of the metal in the atmosphere can produce symptoms in them. A susoeptible person may show symptoms when exposed to the extremely low value of one viorogram per cubic meter of air. Authenticated ''neighborhood cases" .--who.lived near a beryllium plant - seem to substantiate this, sinoe they -J^csed to extremely low concentrations of dust, There are sufficient data available upon which to base a maximal allowable concentration but some investigators belelve that inplant atmospheric concentrations should hot exceed 2 micrograms per cubic meter of|air as an average for an eight hour day, and that no one should he exposed to a concentration in excess of 25 micrograms per cubic meter of jair for any period however short. These are extremely i SPNY 000156