Document 0g7pJ7gvXD8eVD7vQ5geQLKgd

FILE NAME: US Gypsum (USG) DATE: February 12, 1937 DOC#: USG061 DOCUMENT DESCRIPTION: 1937 Letter to FG Johnson from AC Hirth regarding response to letter of January 29. 75 February 12, 1937, Mr, Fred a. Johneon, Manager, Znsulatlng Wool Sales, TJ, 9, Gyp urn Co,, 300 W, Adams St,, Chisago, 111, Dear Mr, Johnson The delay in answering your letter of January 29 has been oeoasioned by ay absenoe from the oity, ITe hare Tory carefully oonsidered the ad visability of permitting Dr, Gardner*s report to be furnished to salesmen generally, and passed from hand to hand. It is our feeling that suoh procedure would be unwise, and that the possibility of the report being twisted and misused by others orershadows the advantage gained. In individual oases we have found it necessary to disouss the report with the oustoaer, He believe, however, that its use should be eonfined to this sphere, Very early in the manufaoture of glass wool we oonsidered the possibility of its having deleterious effects upon those working with it or using it. An investigation was made and It soon developed that there was a soaroity of pertinent experimental work published in the literature. It therefore appeared wise to conduct our own experiments, which procedure had the advantage that the results would apply specif ically to our own commercial grades of glass wool made from our own bmtoh. l .vji' i '- '. f '" -V v< . GP021 0999 Several groups of experiments irere undertaken to eternise what, if any, untoward physiological effeet glass wool night have when it cones in oontaot with the human body* The reasoning behind this work, whloh die* tated the ehoioe of experisents, was briefly as follows* It was assuned that glass wool night enter the body by three routes, by inhalation, by swallowing, and by penetration of the skin. If glass wool dust is breathed, assuming the partlele* are small enough to enter the small air spaoes of the lungs, answers to these questions were soughti Will Inhaled glass wool dust cause a reaotlon in the lung tissue similar to that produced by sllloa dust in silioosist Trill the reaction be at all harmful? If not, what will become of tiie glass wool dust? If glass wool fibers are swallowed - will they produce any serious or permanent injury to the digestive traot? If glass wool fibers penetrate the skin - will the glass aot as a tissue poison? What will become of particles of glass wool that might be injected in the skin? Dr. Leroy V. Gardner of Saranao Laboratory, Saranao Lake, Sew York, undertook two groups of animal experiments, and Ur. Philip Drinker of the Harvard Sohool of Public Health, together with Dr. Albert C. Titus, undertook a third group of experiments. Animal Injection Experiments In determining whether Inhaled glass wool dust would aot in any way oosparable to free silioa dust, it is essential that the exposure be prolonged over a period of many years in order to show up ohronlc effects. So group of workmen in this oountry have used glass wool long enough to show positively whether or not ohronio Injury to the lungs might result. X-ray and olinioal examinations on our workmen with the longest periods of service, however, revealed no unhealthy lung oondition at all. The effeots of Inhaled dust oan be aooelerated in the oase of animal eseporiaoata, and it was for 'this reason - to oheok our inconclusive X-ray findings - that Dr. Gardner's help was solioited. lOGO 3 Animal experiments to determine tho offoot of inhaled dust oon ho performed in two ways* First* the animal an be plaoed in dust-laden atmosphere and made to broatho dusty air for long period of time* Second* the duat in question oan be injected into the animal* bodies* and it i generally reoognised that the type of inflammation or reaction that results indioate to a trained pathologist whether the harmful effects are at all comparable to those produced by free silica dust Because the "dusting" method requires two or more years to get results, the injection or seoond typo of experiment was selected Animals were injected with glase wool dust* both "plain* and "oiled", (oil is applied to some commercial grades of glass wool to reduoe fracturing of the fibers and to prevent dust being iron off during handling). Animals were examined at intervals of several days or weeks for a total period of 285 days Dr, Gardner state Experience in this laboratory and else* where has shown that these methods are adequate to demonstrate the capacity of a mineral dust to produoe fibrosis* Injection of over 20 different types of dust has indicated that if no reaotion ocours in orgsns other than the lungs* none will ooour in the respiratory tract* and that conversely* dusts like silica and asbestos that are knomn to produoe fibrosis of the lungs* also oause fibrosis in other tissues when injeeted in sufficient quantities" Dr. Gardner summarises this eerie of experiments as follows "neither plain nor oiled glass wools have oaused fibrosis or any ohronio progressive reaotion by injection* and therefore, it is s reasonable assumption that their inhalation would likewise fail to produoe such effects" 1001 TZOtIO 7^ 4- Eating Glass Tfool i- A considerable number of reference exist in the literature to oases where elrous performer and individuals with ulterior motives, hare either eaten glass or oauaed others to eat It* Usually in these reports' the glass was in the shape of ehunks or pleoes large enough to see with the naked eye. In no instance that has ooae to our attention did the reports shew that any serious injury was done to the individual by the glass* \ There remained the possibility* however* that long-continued swallowing of small amounts P t extremely fine partioles of glass might produce some ehronio damage to the body* Or* Gardner therefore undertook the seoond series of experiments la whloh fasting guinea! pigs were injeeted with finely ground glass wool by stoaaoh tube* Hone showed any ill offsets even after the injections were repeated* . A Guinea pigs were then fed glass wool du#t, mixed with a portion of grain* before they received their morning rations* After these meals were administered daily for periods varying up to a total of 119 days* examination "failed to diselose evidenee of the glass fragments or any Injury inflicted by them*" \ Dr. Gardner oonoludesi "One may therefore eonelude that the Ingestion of as nuoh as 81 grams of finel^ powdered glass wool* administered in divided doses* will not oause injury in 4 months* \ " time* In the absence of any reaotion at all* it would hardly seem essential to oontinue the investigation further." His concluding statement we think is extremely Q pertinent. It is as follows t "Trusting these findings say allay any svantioism aa to a theoretioal hasard Involved a from the handling of glass wool* I am o Very truly yaurs* Leroy U. Gardner, H.D. Director" 5 Solubility of Glass Wool Ho Information tra found trhioh gara th solubility of gi in body fluida. A knowledge of hotr aolubla glaaa ia in body fluida tra falt to ba aaaantial in anawsriag tho qusstion, *TThat beoomaa of glaaa aftar t antera tha body?" Or. Titua tharfore, under the direction of Ur. Drinker, ran ohemioal experimenta on olubility of glaaa wool in blood aerua. By the same method he aleo obtained the aolubility of quarts (free eilioa) in blood aerua Compared to quarts, glaaa waa found to be extremely aoluble. As a matter of faot the blood aerua had a oertain reaidual aillo a content, and Dr. Titua waa unable to aaoertain whether any of the quarts went into solution during a two-montha period In the ease of glass wool (same types used by Dr* Gardner), however, the quarts content of the serum increased more than fifteen fold during the same period. Cpnolualona Heferring to the original questions, we believe that Dr* Gardner showed that glass wool dust, if breathed, will produoe no harmful effect on the lung tissue comparable in any way to that oaused by aillo a dust. As a matter of fact, in Tiew of Dr. Gardner1s conclusion, wc may assume there ia no, harmful effect of any sort. Zt ia believed that glass wool duet whioh enters the lungs would be removed by the normal action of the *scavenger" oalls of the lymphatio system, and in view of Hr. Drinker' work, that the partile will eventually pass off In solution. The evidenoe revealed by a searoh of the literature, supplemented by Dr. Gardner's experimente, shows that no permanent damage is done to the digestive tract if glass wool is swallowed, either in single large doses or in small doses taken regularly ower a long period of time. 'Vhile it is likely that large pieoes of glass would out the digestive traot, animal experiments reported ia the literature show that this injury heals ooapletely in three or four days, and produces praotioaliy no discomfort. GP021 1003 c3t - 6- From. Dr Gardner's work, It 1* evident that the aotual prooeee of going into solution* that is* the prooess of solid glass being carried off by liquid, doee not giro rise to any tissue poison this indicates that glass in the body will be dissolved and eliminated slowly and oontinuonsly without any injurious or poisonous offoots on the individual ITe trust that this information will assist you in overooalng whatever sales reslstanoe you may meet on this soore. Tours very truly, OTTERS-ILLINOIS, GLASS COIIPAST A dU Hirth,' ob Legal A Patent department. V ' J*-