Document dQ9M8oXMBkzLE6kog3YJmRQvQ

FILE NAME: American Cyanamid (AMCY) DATE: 1951 Mar DOC#: AMCY014 DOCUMENT DESCRIPTION: Unpublished Conference Presentation \ a ^ ^ -5ts' 2L2I!i*NM_>'AipNrD1 M 95 JU V ,J C W O, V-,n S O C I E T Y OF THE P L A S T I C S I N D U S T R 1 2 Preliminary copy of a report to be presented at the Sixth Annual Meeting of the Reinforced Plastics Division to be held at the J Edgewater Beach Hotel, Chicago, Illinois, February 28th, March 1st, 2nd, 1951 . The Society is not responsible for the views expressed. INDUSTRIAL HYGIENE CONSIDERATIONS IN THE MANUFACTURE' OF REINFORCED PLASTICS by William R, Bradley, American Cyanamid Co. Some 250 years ago, an Italian physician, Ramazzini*^ by name, made obse'rva- V tions on the occupations of men to learn if som e factor in their work could-be.,; . .. associated with the illness and disease that he observed in them. He wond?gyedi ' - why those who worked in centain m ines lived such short lives after be'gixudxig.-l'' their employment and succumbed to diseases for which there was no cure.'He i discovered that only slaves and prisoners could be pressed into this type of work, I>1 for death was certain after only a few years of labor. He entered one of these m ines and experienced the foul air which h,e felt played some part in disease,, not knowing that poisonous gases really existed which, together with various harm ful dusts quickly sapped the strength and energies of the w orkers. From here, R&mazzini visited the chem ist's shop and found him laboring in his smoke and fume filled quarters, breathing the m ists and vapors of his many con-? coctions. At the bleaching pit, the workmen disappeared in the hot gases and m ists as they bent over the sulfur vats. And so it went from occupation to occupation. U* Ram azzini found d isease and sickness associated with the conditions of work. But his recorded observations went unheeded by his colleagues, as w ell as by those who followed. ' So it was, that in the early industrial development in this country, men were ex posed to g a ses, m ists, fume, vapors, dusts, excessive heat and cold, and ex ces T sive noise, with little regard to the possible injurious nature of a number of these substances. In som e instances, even though it was observed that life w as' short ened and that others became physically unfit for further employment in the space of only a few years, there was little attention given as to why these things were so. In fact, in som e instances, exposure to harmful and irritant substances was ; J accepted as an unavoidable, although disagreeable, condition of em ploym ent. In-' dustrial illnesses, like phosphorous poisoning, mercury poisoning, silicosis from free silica dust in the lungs, and m anganese poisoning for years went undetected and unassociated with employment. Only in com paratively recent years, has there come the understanding that cer ] tain industrially used substances may be toxic or harmful if they are permitted to exist as atmospheric contaminants in work places, or if employees are sub / i - Section 16, Page 1. jected to physical contact with them. It was also realized that harmful substances might enter the body through the lungs and be absorbed into the blood stream or might be absorbed through the skin, as well as be taken by mouth. With this under standing came the diagnosis and treatment of illness by industrial physicians and the recognition, evaluation and control of toxic substances in the working environ ments by industrial hygienists. Today in certain of our larger industries, these individuals, working as teams and together with others have undertaken the study of raw materials, intermediates and finished products in small animal laboratories to investigate their toxic properties. Even though such studies have been under way for several years, toxicologists are the first to say, "we have only made a beginning." The study of lead poisoning has been continuing for more than 20 years, but a great deal more must be learned before it may be written off as finished. Toxicologists have classified dusts, for example, into those that are harmful and those that are inert, when breathed into the lungs. They have also learned that only the tiniest of particles, those less than 1/25000 of an inch in diameter, too small to be seen with the unaided eye, can pen etrate deeply into the air sacs of the lungs, Their studies have revealed the vola tile solvents that are harmful whether inhaled or absorbed into the skin, and also just how they produce illness within the body. The studies assume greater impor tance today in the roll of preventing illness among industries' workmen, particu larly in light of investigating the new and useful chemical substances that today are entering the industrial market. One may quickly list those new chemicals u se ful to the Reinforced Plastics Industry that were unknown only a few years ago;^. ' yet, without which there would be no plastics industry. Even now Industrial Physi cians are adding to their knowledge in the diagnosis and treatment of illness in men employed in the Plastics Industry and in recognizing and pointing out the dif ference between illness resulting from their employment and that from non-indus trial causes. For not all sickness can be laid at industry's doorstep; in fact, the greater proportion of ill health among those industrially employed is considered due to non-industrial causes. THE INDUSTRIAL HYGIENIST AT WORK Industrial Hygienists, frequently, rather arbitrarily, have established certain max imum limits on the concentration of harmful air-borne contaminants that are per mitted to exist in the working environment, below which limits it is not anticipated that occupational illness will occur. However, these protective limits apply to a relatively few of our commonly used industrial materials. Yet, even though the entire field of Industrial Health may be considered as comparatively young, much progress has been made; the health of the employee in industry today is tremend ously improved over that of a few short years ago. In fact, it is generally agreed that engineering control methods may be used in industry so that even highly tox ic substances may be handled safely and without exposure of employees, and that occupational illness is preventable. There is the challenge for Industrial Hygienists to make concentrated study of the comparatively new Reinforced Plastics Industry. They are interested in studying and classifying the raw materials of this industry and to designate which must be handled with care. With their air sampling instruments, they can measure and ana Section 16, Page Z. ulyaztee tthhee pcornecseenntcreatainodn aomf oguansteso,f vaairpocrosn, tmamisintsanatnsdtdhautstms,igahntderxeicsto.gnIfizneu,isaanndceevoarl harmful substances are present, they are concerned that mechanical exhaust ven tilation be provided with hooded enclosures at places where dusta and m ists and vapors might escape to the workroom air. Applying engineering control m easures to carry away and to trap these substances from the standpoint of preventing ill health is their specialized field. When studying how m aterials are handled, they can determ ine just where and how a worker may be exposed and can show jvhere personal protective equipment such as gloves, aprons, shoes, clothing or respira tors, and face masks may prevent contact with irritant substances. Transporting solvents by pump through closed system s from storage to the reac tion process w ill prevent the exposure to splashing and to inhaling vapor that would exist if the solvent were carried in open pails or by other open handling methods. Pumping through a closed system of piping may also speed production and lessen its cost. There is always something gained by the careful application of Industrial Hygiene practices. THE DERMATITIS MYSTERY In one industry, not long ago there occurred a m ysterious episode of derm atitis. In looking for the cause of this difficulty, the plant management were u nsu ccess ful in finding any sign of the offender. Some thought it might be poison ivy, due to its occurrence in the early sum m er, but this proved not to be the case. Various insects were also suspected of producing this skin rash. Although the plant area involved in this occurred in the difficulty past. It is was a dusty place in true there had been which to work, a case of skin rnaoshsuhcehreafafnlidcttihonereh,ad but this tim e nearly everyone in the building was having trouble. In fact, produc tion had fallen so much that the management were concerned about meeting their com m itm ents on sa les. The em ployees, too, were very much concerned and some were considering seeking employment elsew here, to get away from the m ysterious akin trouble. The investigation made by the Industrial Hygienist called into the picture support ed the early findings of the plant management, but in routine checking and analys ing raw m aterials, he found that a new and improved ingredient had been added to a powdered product by the supplier. Contacting the supplier, it was learned that there was no information whataoever on the toxicity of this newly added ingred ient, nor was there any indication on the label, accompanying the product that a new ingredient had been added. The m aterial at an early step in the process was dried in a sm all rotary kiln, from which there escaped rather sizeable amounts of fine dust particles that dispersed to the entire work area of the building. This situation was revealed by the Industrial H ygienist's dust counting and air sampling technique, and in further study, his findings ruled out any possibility of other cau ses of this difficulty. It is true that no adequate washing or shower facilities w ere available for the men, and this dust was entering their work clothes which they wore from the plant to their hom es. Here, then, was a continuing source of skin contact that pointed to the cause of the derm atitis. Section 16, Page 3, A hooded enclosure was designed for the feed end and discharge end of this small kiln. Exhaust ventilation *as applied to these nooods. The dust that formerly had been air borne throughout the plant was now transported to a dust collector where most of it was trapped in large cloth bags. The space around these bags was in turn enclosed and the excess air discharged to the outdoors. New toilet and wash room facilities were also provided. As a result of all this, the dermatitis rapidly cleared, the plant area became a much more desirable place in which to work, due to the absence of airborne dust, the employees were very much pleased with the turn of events, and the manage ment was again able to breathe easier. The product trapped in the dust collector was salvaged in such quantities that the ventilation installation paid for itself within a period of six months. Later, the suppliers of this new added ingredient learned to their dismay that they had marketed a product highly irritant to the skin, without indication to the customers through caution labeling. TROUBLE WITHOUT WARNING Another episode deals with solvent handling: One afternoon, the Industrial Hygien ist's telephone rang and a rather excited voice on the other end of the line unfold ed the story of sudden illness on the part of employees, severe enough to result in the hospitalization of a few. The Industrial Hygienist went right over to the plant with his air sampling instruments. After studying the process, analytical m easurem ents showed the concentration of a particular solvent vapor in the work room to be e x c e s s B 'e 1* high The vapor, although tolerable, quite likely could have caused the sickness. The investigation disclosed that a raw material requir ed dissolvin g and thinning. It was known that this particular solvent would do the job. Accordingly, the m aterial was put in an open kettle and the solvent added, but the reaction did not proceed very rapidly, and to speed the process, it was decid ed to install steam coils in the tank and apply heat. The application of heat did the trick, but at the same time released excessive quantities of solvent vapor into the workroom air. The episode of illness and the stopping of production was of grave concern to all. However, the Industrial Hygienist, from his experience, recommend ed putting a cover on the top of the kettle, installing a manhole with a small hood enclosure, through which materials could be added with safety, and using m echan ical exhaust ventilation from the kettle and the manhole hood. The cover was neat ly fitted around the shaft of the agitator and the exhausted air was discharged to the outdoors high above the roof of the building. The concentration of solvent va por rapidly diluted in the outdoor air to the point where it did not create any air pollution problem. Again the plant settled back to work, but in this case, informa tion on the toxicology of the solvent vapor was known and published. How much better it would have been to have had the Industrial Hygienist review the proposed p rocess and apply preventive control m easures on the blueprints to be installed at the same time as the process. TOXICOLOGY OF RAW MATERIALS The toxicology of some of the raw materials used in the Reinforced Plastics In dustry is referred to briefly below. More complete discussions of these and other substances may be found in the industrial hygiene and toxicology texts by Patty^ and by Fairhall.^ Section 16, Pago 4. Styrene is a solvent widely used in the Reinforced P lastics Industry because of its ease of polymerization. The physiological response to the inhalation of styrene vapor and to the contact of styrene vapor with the skin has been published by Rowe, by S p e n c e r , a n d by Carpenter. 1 Absorption of the vapor is mainly through the respiratory tract and m both animals and man, styrene is metabolized and excreated in the urine. Judged from the effect on animals, a maximum con centration of vapor permitted in workroom air has been suggested as 400 parts of vapor per million parts of air. This limit has been suggested for repeated expo sures of men for an eight-hour work day. However, the concentration of 400 parts per million may be disagreeable to some persons, and in a few, may cause a transient irritant effect on the eyes and nose. For this reason, the American Conference of Governmental Industrial Hygienists recommend a limit of 200 P.P.M. The sampling and analysis of styrene vapor in the air is easily accomplished, using the method described by Rowe and others. Usually, styrene is handled in dustrially in closed vessels equipped with positive exhaust ventilation. The use of respirators approved by the United States Bureau of Mines for protection against the inhalation of organic vapors may be useful for short time intermittard exposure to low concentrations of styrene vapor in air. Diallyl Phthalate has been the subject of investigation by McOmie and Anderson. They report that diallyl phthalate is a mild irritant to the skin and eyes of rabbits, and that contact with the skin should be avoided, through the use of protective gloves or clothes. Where sufficient diallyl phthalate was introduced into small animals to produce death, sub-lethal poisoning was characteristic by weakness and mild depression. Liver damage and lung congestion were the chief pathologi cal findings. The toxicity of diallyl phthalate is greater than that of other phthalic esters on which data is available. Its greater industrial hazard in the plastic in dustry is the possibility of chronic illness through long continued and repeated skin absorptions. This points to the desirability of good sanitary facilities for washing and taking showers, the use of rubber gloves when handling the chemical, and for a program of wearing clean work clothing. No maximum permissible ex posure concentration has been established for this substance. Dibutyl phthalate has been reported by Lehmann and Flury^ to produce irritation of the mucous m em branes, salivation, re.stle? snes s and fatigue, with no after effect and with quick recovery in cats, when exposed for 5-1/ 2 hours to 88 parts of dibutyl phthalate per million parts of air. The physiological response to vapor exposure of cats to dimethyl phthalate has been reported by the same authors^ as giving about the same response when the concentration reached 252 parts per million. It does not seem likely that such a concentration would exist in air mixtures at room temperatures due to its vapor ten s ion. If dibutyl and dimethyl phthalates are heated or sprayed, control of the work en vironment to avoid skin contact and inhalation is indicated. No maximum permis sible limit of industrial exposure has been established for these compounds. T ri-o-cresyl phosphate exists in three isomeric forms which possess differences in toxicity. The ortho and metacresyl phosphates are colorless, practically odor- Section 16, Page 5. l e s s li qui ds whu. h a r e s t a b l e and n o n - v o l a t i l e . T h e p a r a i s o m e r e s s t . ^ m the fo r m oi c r y s t a l l in e n eed les . Insoluabie in w a te r, these phosphates are m i s c i b l e with the c o m m o n s o l v e n t s and thi nners and with ma ny v e g e t a b l e oi ls . The e x p e r i m en t a l w o r k by S m i t h ^ sho we d that tox ic oiogic a !ly t r i - o - c r e s y l phosphate d i f f e r s t r o m the c o r r e s p o n d i n g c r e s o l s , phenols, or rhetr ph os ph u r i c a ci d e s t e r s b e c a u s e f o l l o w i ng c u t a n e o u s o r i n t r a v e n o u s i nj e c t i on s tn a dog or c a t , a l l a c c i d p a r a l y s i s ol the p o s t e r i o r e x t r e m i t i e s and to a l e s s e r d e g r e e of the a n t e r i o r e x t r e m i t i e s o c c u rs after a latent interval va rying from five to thirty days. This delayed action 01 i r i - o - c r e s y l p h o s p h a t e in t he a n i m a l b o d y a n d i t s s p e c i f i c e i f e c t o n n e r v e t i s s u e s is i n t e r e s t i n g . T h e r e e x i s t s r e p o r t s m the l i t e r a t u r e of f l a c c i d p a r a l y s i s of the up p er and l o w e r e x t r e m i t i e s in p e r s o n s who ha ve taken t r i - o - c r e s y l phospate by mouth as an ad ulterant in sa lad oil and fat sub stitutes. Slow but c o m p l et e r e c o v e r y is reported to have o c c u r r e d . One does not anticipate difficulty in ha n d l i n g t r i - o - c r e s y i p h o s p h a t e i n t he p l a s t i c s i n d u s t r y , b ut t h e o p p o r t u n i t y 01 c o n t a mi na t in g food stuffs or l unc he s that m a y be c a r r i e d into the w o r k i n g a r e a of plants should be recognized. No industrial toxications have been reported; h o w e v e r , the s p r a y i n g of t r i - o - c r e s y l phosphate or v o l a t i l i z a t i o n by heat should be c a r e f u l l y c o n t r o l l e d , as a b s o r p t i o n ol the c o m p o u n d t h r o u g h the i n t a c t s k i n has been d e m o n s tr a t e d . Hodge^ and S t e r n e r have made furth er contributions to the t o x i c o l o g i c a l l i t e r a t u r e on t h i s c o m p o u n d , a n d m e t h o d s 01 d e t e c t i o n a n d d e t e r m i n ation have been reported by Jacobs.^ No m a x im u m p e r m is s ib l e limit for indus*-ial a t m o s p h e r e s has been est ablish ed for this compound. B e n z o y l p e r o x i d e is us e d in the R e i n f o r c e d P l a s t i c s i nd ust ry as a c a t a l y s t b e c a u s e of its e f f e c t i v e n e s s in b r i n g i n g a b o u t p o l y m e r i z a t i o n . In s p i t e ot its r a t h e r e x te n si v e use in the flour m illing industry as a ble ach in g agent, v e r y little i n v e s t i gati on on the t o x i c it y of b e n z o y l p e r o x i d e has been m a d e and so far, no i n j ur i ou s e f f e c t s oi i n d u s t r i a l i m p o r t a n c e h a v e b e e n noted. It is known , h o w e v e r , that b e n zoyl peroxide may inhibit growth in certain plant and animal feeding. E xp e rim e n t s u s i n g t h e s e p l a n t s h a v e i n d i c a t e d a l o s s ot w e i g h t . A l t h o u g h b e n z o y l p e r o x i d e p o s s e s s e s a low o r d e r of toxicity and no m a x i m u m allowable concentration has been set for the p r e s e n c e of this dust in w o r k r o o m a t m o s p h e r e s , it is c o n s i d e r e d w i s e to a v o i d d u s t i n h a l a t i o n d u r i n g h a n d l i n g of t hi s m a t e r i a l . T h e u s e ol d u s t r e s p i r a t o r s is s u g g e s t e d to a voi d i nhal ati on if the handling te chn ique cannot be m a d e dust free. The drying agents such as naphthenates or petroleum naphtha have a defatting a c t i o n f o l l o w i n g c o n t a c t wi t h the s k i n . In the e v e n t of p o s s i b l e s k i n c o n t a c t , t h e r e fore, the use of rubber gloves is indicated. The added m e t a l s . s u c h as cobalt are u s u a l ly p r e s e n t in v e r y s m a l l quantities. T h e r e is no published in f o rm a ti on on the t o x i c o l o g y of c o b a l t n a p h t h e n a t e a s s u c h f r o m the s t a n d p o i n t o: the v a p o r i n halation, nor has any m a x i m u m p e r m i s s i b l e limit of e x p o s u r e been es t ab lish ed . Of the m a t e r i a l s c o m m o n l y used as f i l l e r s , s i l i c a , in the f o r m of s i l i c a flour, should r e c e i v e s p e c i a l attention. Since ancient t i m e s , it has been thought that c e r tain dusts c a u se d d i s e a s e of the lungs; in fact, the w r it i n g s of R a m a z z i n i ^ d i s c u s s e s it. Illness o c c u r r e d am ong t r a d e s m e n w h ose w o r k w a s in "hewing m a r b l e o r s t o n e s out of r o c k and in p o li s hi ng and cutti ng t h e m . " He r e c o g n i z e d that the i nh a l a t i o n of dust in s o m e w a y w a s r e l a t e d to the c o n d i t i o n ot the l ung s of t h e s e p e r s o n s w h e n s e e n in a u t o p s y . It is not s u r p r i s i n g to f i nd s i l i c a e x p o s u r e s in i n s e c t io n 16, Pa ge 6. dustry, since the bulk of the earth's crust is siliceous material. There is a great quantity of animal experimentation referred to by Patty^ and by Fairhall^ showing that the inhalation of free silica (Si02) causes a fibrotic disease of the lungs follow ing a massive invasion of the pulmonary tissue. The production of silicosis depends upon the composition of inhaled dust, the number of particles of inhaled dust, the size of the particles, and the length of time during which particles are inhaled. Workmen handling free silica should avoid creating and inhaling dust. Dusty pro cesses should be equipped with exhaust ventilation to prohibit free silica from e s caping to the workroom atmosphere. In the absence of such environmental con trol, workmen should use respiratory equipment approved by the United States Bureau of Mines ^ for protection against the inhalation of toxic dust. Asbestos in finely divided particulate form is capable of entering the lungs by in halation. While asbestos is a hydrated magnesium silicate and contains little or no free silica, Lanza^ concludes from his study that prolonged exposure to asbes tos dust may cause pulmonary fibrosis, termed asbestosis. The production of silicosis is apparently much more rapid than the production of asbestosis, but again the disease depends upon the quantity of dust that is inhaled. Report of a comprehensive study of asbestosis has recently been made by Vorwald^ et al. It has been recommended that the maximum perm issible limit for free silica dusts and for asbestos dusts in the working environment be 5 million particles of dust per cubic foot of air for eight-hour daily exposure. The Industrial Hygienist em ploys a special technique of atmospheric sampling and actual dust particle count ing, using a microscope in order to make determinations of atmospheric dust con centrations. The figure of 5 million dust particles may be compared with the per m issible limit of 50 million particles per cubic foot of air for dusts of the inert or nuisance type, those not considered generally to be productive of fibrosis in pulmonary tissue. The clays that may be used as fillers are mainly silicates and contain relatively small amounts of free silica, usually less than 5 % and are classified as nuisance dusts, having a permissible limit for atmospheric dustiness of 50 million particles per cubic foot of air. Fiberglas used in the Reinforced Plastics Industry has been a subject of consid erable investigation from the standpoint of its effect on those who work with the material. There has been some irritation of the skin in people who handle it, but most of these cases have cleared up rapidly and the workmen apparently suffered very little further discomfort. The manufacturers of glass wool substances sug gest that workers wear clothing loose at the neck and wrists. More important is the recommendation that workmen take a thorough shower at the end of their day's work, using plenty of warm water and soap. Soap and water proved most effective in removing particles from the skin. It is also important that the work clothing be frequently laundered and that the workmen change to street clothes at the end of the work day. Gardner3 conducted extensive investigations on the effect of in haled glass wool and reported that "apparently even the finest textile glass set up as an atmospheric dust is not inhaled in appreciable concentrations and does not produce any dangerous effect upon the lung". For over a year, he exposed experi mental animals to high dust concentrations and found very little in the way of air S ection 16 , Page 7 - / borne fibeia that penetrated deeply into the lung. Siebert12 has published a verythorough investigation for the manufacturers of fiberglas that includes a study of the men engaged in production where he found no ill health. Sulzberger and Baer have reported on the effects of fiberglas on animal and human akin* concluding that reactions such as "itch", were of a transitory and superficial nature. Calcium Carbonate dusts are usually considered in the nuisance category, from the standpoint of industrial hygiene. It has been known, however, to produce ir r i tation of moist skin, particularly when workmen are exposed to heavy concentra tions, and may be perspiring freely. HIGHLIGHTS OF PROCESS CONTROL The industrial Hygiene considerations of various processes in the Reinforped P las tics industry deal with controlling the environment of the working places to pre vent the inhalation solvent vapors or dusts and in protecting employees against liquid contact with the skin. Also consideration should be given to the provision of adequate shower and wash rooms and maintaining a high standard of personal work er cleanliness. A program that will pay dividends in a successful operating experi ence is one of education among employees in the care they exercise in handling ch em ical substances used in the industry. If resins that enter the plant in drums are added to open mixing kettles and likewise the solvents and catalysts are add ed to these same kettles, then consideration should be given to providing enclosures for the top of these kettles and using positive mechanical exhaust ventilation to prevent vapors from escaping to the workroom environment. The use of fillers in the form of dusts should be done with care to avoid inhalation of the dusts, particu larly those containing free silica or asbestos. Local exhaust ventilation should be established where resins are sprayed on to reinforcing materials. The application of sm all sheet metal enclosures at the bed of molding machines with the exception of the working face and applied exhaust ventilation laterally to remove solvent va por has been s u cces s fu l. It has been possible to make this en closure, adapting the design and construction of the sheet metal so as not to interfere with the operator or his work. Certain finishing operations are likely to be dusty, such as sawing and grinding, and while these dusts are mainly considered as nuisance problems rather than as a serious health problem, exhaust ventilation applied to saws and grinders, follow ed by dust collection has been successful in other industries, particularly the wood working industy. Control of the working environment from the standpoint of main taining good health among employees costs money, and the benfits in some cases may be intangible.* Yet the provision of a good working environment points to con tinued production, the increased opportunity to produce at a greater rate, and in attracting and holding good w orkm en in the industry. It has been said that "produc tion comes from people". Providing a clean and healthful place where people may work certainly benefits production. INDUSTRIAL HYGIENE SERVICES Where are the services of Industrial Hygiene available? Many states have establish ed bureaus of industrial hygiene within their state department of health or depart- Section 16, Page 8. ment of labor, and these groups are ready to advise industry on problems of the working environment. A few insurance companies staff industrial hygiene per sonnel who are made available to assist their compensation risks. Several large companies maintain their own industrial hygiene groups. In addition to these peo ple, there are a few private consultants, both as individuals and as groups, in the field of industrial hygiene. It may be that the Reinforced Plastics Industry would consider the s erv ices of a consultant on the subject of industrial hygiene to conduct a survey of a represent ative number of member organizations of this group. Such a person might well be staffed by the Society of the Plastics Inudstry. He could ascertain the status of various processes from the standpoint of employee health maintenance, deter mine where preventive measures may be taken against potential illness and de velop advices leading to a continued production with the avoidance of both health and nuisance problems. Of particular value would be consultation with the Indus trial Hygienist when new processes or new chemicals are anticipated, so that precautionary provisions for a good work environment can be established well in advance of production. This, then is the challenge for modern industry. REFERENCES 1. Carpenter. C. P., C. B. Shaffer, C. S. Weil, and H.F. Smyth, Jr. J. Ind. Hyg. Toxicol., 6, 69 (1944) 2. Fairhall, L.T., Industrial Toxicology, Williams and Wilkins, Baltimore (1949) 3. Gardner, L.U., R esearches of Mellon Institute (1940) 4. Hodge, H., and J.Sterner, J.Pharmacol., 79 225 ( 1943) 5. Jacobs, M.B., Analytical Chemistry of Industrial Poisons, Hazards and Sol vents. 2nd ed.,Interscience, New York (1949) 6. Lanza, A.J.Silicosis and A sbestosis. Oxford University P r e ss. New York ( 1938) 7. Lehmann, K.B.and F. FTury, Toxicology and Hygiene of Industrial Solvents. Trans. By E. King and 8. McOmie, W.A.and H.H.Ande rson.Univ.Calif .Publ. Pharm acol.,2,205(1947) 9. Patty,F.A..Industrial Hygiene and Toxicology 2 vol. Interscience, N.Y.(1949) 10. Ramazzini.B. DeMorbis Artificium,Latin Translation by W.C.Wright. Univ. of Chicago P r e ss, Chicago, 1940 11. Rowe, V .K ., G.J. Atchison, E .N . L u c e , and E . M . A d a m s , J.Ind. Hyg. Tox icol. , 25 348 (1943) 12. Siebert, W.J. F ib erglas Health Hazard Investigation. Ind. Med. 11, 6, (1942) 13. Smith, M.I. et al. Studies on the Pharmacology of Certain Phenol Ester. Natl. Inst. Health Bull. No. 160 (1932) 14. Spence, H.D., D.P.Irish, E. M. Adams, and V. K. Rowe, J. Inc. Hyg. Toxicol., 24, 295 (1942) 15. Sulzberger, M.B. and R.L.Baer, the Effect of Fiberglas on Animal and Human Skin. Ind. Med. 482, (1942) 16. United States Bureau of Mines Information Circular 7513 (1949) Washington,D.C. 17. Vorwald, A.J., T.M.Durkan and P.C.Pratt. Experimental Studies-of Asbestosis, Arch. Ind. Hyg. and Occup. Med. 3, 1 (1951). Section 16, P age 9- QUE STION - Presented by Calhoun Shorts, Pacific P la stic s Co. Is the itching caused by glass fibers a mechanical or toxic effect? ANSWER - By William R. Bradley, American Cyanamid Co. The so-called itching that has occurred when handling fiber glass under dusty conditions has been shown to be entirely a mechanical effect. QUESTION - Presented by William Cruse, The Society of the Plastics Industry Are you familiar with a bill now bpfore Congress which will prohibit the use of certain chemicals in the food processing industries? ANSWER - By William R. Bradley I am not familiar with details of such a proposal. However, it would seem to be more a question of residual concentration of chemicals to be permitted rather than outlawing certain chemicals in the food pro cessing industries. The human body is such a complex chemical plant that arbitrarily prohibiting use of chemicals without sufficient toxicol ogical study would be unwise. QUESTION - Presented by Robert B. White, Laminated Plastics, Inc. Is there any danger from inhaling styrene fumes? ANSWER - By William R. Bradley Styrene vapor may be inhaled in concentration up to 400 p.p.m. for long periods of time without much opportunity for harm. Styrene, when absorbed in the blood, is rapidly detoxified. QUESTION - Presented by F. H. Humphrey, Fleet Fiberlast, Ltd. (1) Can cases of dermatitis be caused by monomeric styrene? (2) Can you recommend a specific type of skin cream? ANSWER - By William R. Bradley (1) Styrene can cause dermatitis following promiscuous use and handl ing that would involve continued contact with the skin. Styrene may re move the natural fat of the skin. (2) Water-insoluble type creams. QUESTION - Presented by James Lunn, Lunn Laminates From the standpoint of industrial hygiene, what are the most serious problems to consider in the field of Reinforced Plastics? ANSWER - By William R. Bradley In my opinion the most serious health exposure problem in the Rein forced Plastics industry is the opportunity for intermittent inhalation of toxic dusts and vapors. Section 16, Page 11