Document KR2vBOzjevmVymrEbrRo0G5kX

Volume 9 < NATIONAL SAFETY CONGRESS TRANSACTIONS ELECTRONICS and ELECTRICAL EQUIPMENT NATIONAL SAFETY COUNCIL 425 North Michigan Avenue Chicago, Illinois 60611 SCF-ALLF-02930 Joint Session with Electronic end Electrical Equipment Section OCCUPATIONAL MEDICINE IN THE ELECTRONIC AND ELECTRICAL INDUSTRY By HARRY B. TEBROCK, M.D. General Telephone ft Electronics Sendee Carp* New York, N. Y. Probably no other industry has developed so rapidly, made greater inroads into the intricacies of science, or taxed the imagina tion and ingenuity of man more than the electronics industry. From the simple! hum ble beginnings of the crystal set radio and vacuum tube to the complicated marvels of TV microwave devices, computers, lasers, etc., electronic engineers continue to push back the barriers of the seemingly impossible to accomplish the incredible. However, in the course of such achieve ments numerous safety hazards, toxicological problems and industrial hygiene difficulties have been encountered. Naturally, in any electronic operation one has to deal with a variety of solvents, gases, (dating chemicals, caustics, adds, fire and explosive hazards, industrial and diagnostic x-ray, noise, toxic plant effluents, etc. I shall treat hurriedly of these common universal hazards in order to provide time for the more exotic issues in the electronics industry. The common chemical hazards indude mercury, lead, arsenic,- cyanides (plating), hydrogen sulfide, molybdenum, germanium,' trichloroethylene, beryllium, magnesium, phosphine (deborane), methylene chloride, photo resist (mixture of polyvinyl, alcohol, ethyl alcohol and ammonium dichromate), caustic, hydrofluoric and other adds, sulfur dioxide, ammonia, amyl acetate, amines, vanadium, yttrium, europium, barium, stron tium, caldum, cadmium, zinc, manganese, nickel, the epoxy resins, polyurethane resins, radioactive materials, and phosphors. Phosphors With the exception .of the phosphors, you undoubtedly have had experience with all of the aforementioned chemicals, both as to their degree of hazard and the safeguards necessary to control these hazards. However, to some the word phosphor may be a rela tively new term, as it is primarily confined to fluorescent tube and TV tube manufacture, both monochrome and color. By definition, a phosphor is a combination of chemicals blended together to produce a new chemical structure with characteristics different from its constituents and capablp of luminescence. In the early development of luminescent phosphor chemicals, you may remember beryllium and the resultant toxicological hazards it presented before eventually being brought under control. Hard on the heels of the fluorescent lamp came a new electronic device: the television receiver. Furthermore, the development of color TV in 1954 en tailed the use of new and exotic phosphors not previously employed. Looking back upon the history of beryllium phosphors, one may anticipate that new industrial hygienic prob lems will come with the new phosphors. Regrettably, as in the early days of beryllium use, no toxicological information of suffi cient scope b available to give one a back ground in the approach to management of the clinical problems of workers who are exposed to these new materials In their /occupations. The physician b industry, therefore, must devise an approach to determbe the level of toxicity and the extent of a medical engineering control program to protect employees as well as any potential product liability. Let me outline briefly how occupational medicine might attack such a problem. Two mab issues present themselves: 1. That of exposure to the raw materials used to make the powder or phosphor covering the face of the TV tube -- m this instance europium-activated yttrium ortho vanadate, used to produce a superior color and brightness as compared to the older and relatively less toxic silver-activated zinc cadmbm sulfide. 2. That of exposure to the finished phos phor after it has been fired and a new chem ical structure formed -- new b crystalline structure, solubility particle size, and new b its toxicological properties. As the name implies, this new solid state compound europium-activated yttrium orthovandate consists of a mixture of the metallic 5 1968 National Safety Congress clement vanadium as an orthovanadate com 3. Chest x-ray (14x17 PA) repeated an bined with yttrium, all activated in the nually. . presence of specific quantity of the rare earth europium. The' three components of this new luminescent phosphor all contain their own individual toxicology, with vana dium being the only one of which we have some depth of knowledge. The literature and scientific experience is conspicuously devoid 4. Vital capacity -- repeat every six months. 5. Body weight and blood pressure -- repeat every six months.. 6. Complete blood count at pre-employment -- repeat annually. 7. Thymol turbidity annually. of data regarding the rare earths yttrium 8. Urinalysis annually -- urine albumin and europium. However, particularly in the every six months. electronics industry, the rare earths are being utilized to an'ever increasing degree in the production of new types of alloys, microwave devices, lasers, masers, insulators, capacitors, 9. Urinary vanadium levels repeated an nually or at any time signs of vanadium intoxication may appear. semiconductors, fcrroelectrics, and probably As a result of this type of medical pro most of all in the manufacture.of powders gram in effect for the past five years we or phosphors for color TV screens in order can now report that: _ ^ to produce more vivid color reproduction. 1. Exposure of a plant population (3,000 Pharmacology and toxicology reveal that the rare earths possess a relatively low level of toxicity. Vanadium and its compounds, on employees) has resulted in an incidence of 30 per cent annual rate of minima] injury by vanadium -- all reversible. the other hand, are known to be definitely 2. No chronic or systemic disease effects tome. Therefore, we must gear our controls were found. to the most toxic element of the phosphor; 3. No significant x-ray changes were ob namely vanadium. served over a five year period. No blood The human response to vanadium has been dyscrasias or elevation of blood pressure well documented. The symptoms are usually or changes in pulmonary function. as follows; conjunctivitis; irritated nasal 4. The incorporation of vanadium as the passages with mucous discharge; irritation of respiratory tract with bronchitis and bronchospasm; chest pain with pneumonitis, dyspnea, and paroxysmal cough; weakness persisting after exposure; and, occasionally, palpitation. A greenish black discoloration orthovanadate into the crystalline lattice of the phosphor apparently results in the formation of a compound of much lower toxicity than that of vanadium pentoxide alone. of the tongue is frequently present, as is a 5. Operations were begun in 1963 and to contact-type dermatitis with associated hyper date the population at risk averages 3,000 % sensitivity. Allergy is a factor, as some people may react positively to patch tests people with 20,000 man hours of expo sure. No toxicology of a permanent dam with a sodium vanadate solution. aging nature has been observed in any of Because of these facts and because so little our exposures during this time. else is known particularly in reference to the With the foregoing experience and the f finished TV phosphor and its application, the fact that we can keep our exposure levels medical department decided upon the fol to below 0.5 MG/M,, the calculated safe lowing medical control program: level, we now can relax our medical pro 1. Initial selection of, workers is made to exclude, from exposure any new em ployees haring any chronic disease of the lungs or respiratory tract such as chronic bronchitis, pulmonary emphysema, nasal gram to some degree. However, in spite of the excellent prophylactic effects of pre venting occupational disease from this toxic material, it is necessary that continuing study be exercised to ascertain if delayed effects will occur such as those which oc or sinus infections, conjunctivitis, allergic curred with beryllium phosphors. disease of the skin, or other allergies. No discussion of occupational medicine's 2. Complete pre-employment physical exam part in the electronics industry would be ination repeated annually. complete without considerations of hazard 6 I Occupational Health Nursing Committee control in laser production and use; also the use of epoxy resins and, as you will recall, the recent apprehension regarding x-radia tion from color TV sets. Lasers Laser, or "light amplification by stimu lated emission of radiation," is an incredible device developed as recently as 1960. There are many projected and actual applications for lasers. For instance, in the field of com munication as a possible technique for range determination of both terrestrial and satel lite vehicles. Also as a clinical tool in certain ophthalmic or other biomedical procedures. For the welding of refractory metals, or as a military tool to fit into selective weapons systems as a new weapon or as the ultimate in and-ICBM weapons. Prevention is the most important aspect of laser safety. Laser is potentially a serious hazard to the eye. Specific levels for safe viewing have been calculated and may be achieved by a combination of distance or suitably optically-absorbing lenses. Specular reflections of laser beams possess health hazard potentials. Subjective brightness of the lesser spot or lack of immediate sensa tion is no measure of its physiological haz ard. The laser working environment should be considered off limits for all but those trained and associated with the instrument Procedures involved in setting up a con trol program against laser hazards in indus try arc much the same as for other toxic exposures. Success depends on complete orientation, understanding, and cooperation by all concerned. The essentials are: 1. Responsibility for safety rests with the supervisor, assisted by medical safety and the industrial hygienist 2. All persons assigned to laser operations to be formally indoctrinated on hazards and controls, especially as they apply to the equip ment in use. 3. All such persons to receive a medical evaluation prior to taking up these activities. This will include visual acuity, a complete ophthalmologies! examination, and whatever other procedures are necessary to elicit evi dence of pre-existing disease or conditions which might .be aggravated by laser expo sure. Persons legally blind in one eye are not suited for assignment. The medical eval uation to be repeated at yearly intervals and immediately after accidental excessive expo sure. 4. Each laser source and its characteristics to be reported to the medical and safety department before activation. As with all significant industrial hazards, the best control is at the source; personal protective devices are to be regarded as "just in case". Some of tire principal points include: a. Details of output capacity of each device should be attached thereto. b. The beam should be controlled bo as to eliminate exposure to operators, bystanders, and the public. c. Warning signs should be posted for , employees and anyone approaching the area. d. Djrcct or reflected viewing of the beam must be eliminated. e. Protective laser goggles may be used . for specific wave lengths up to their rated power resistance. f. Electrical hazards should be elimi nated by locked switches, procedures for bleeding off capacitors, etc. g. Lasers should never be left un attended when energized. h. Light pumps (flash tubes) should be shielded to protect eyes from glare. i. Exposure to cryogenic materials (for cooling) may be avoided with gloves and aprons. Eye shields will protect from splashes or explosions of flash tubes. j. High voltage supply equipment should be checked against x-ray examination and suitable shielding provided as necessary. Epoxy Resins Epoxy resins or thermosetting plastics have considerable application in the elec tronics industry and do present a problem to industrial medicine. Epoxy resin systems contain two reactive components -- the un cured basic resin and a curing agent (also known as a hardener, catalyst, setting agent, dr activator). When the two components are mixed together, the resulting cured, product is a hard plastic having excellent chemical resistance, hardness, adhesive qualities, elec trical properties, and strength. When com pletely cured or hardened, these materials pose no appreciable toxic hazard. 7 1968 National Safety Congress The uncured resin is usually the condensa tion product of "Bis Phenol-A" and epichlorohydrin which, at room temperature, can be other in the liquid or solid state. Fillers such as fiberglass silica flour, abestos, and diatomaccous earth may be added to the uncured resin. Diluents such as organic solvents may also be added. Curing agents commonly used include aro matic or aliphatic amines, add anhydrides, organic adds, polyamides, and organic per oxides. The chemical process of curing can be done at room temperature (cold cure) or at elevated temperatures. The curing time will vary from a few minutes to several hours, depending upon chemicals and tem peratures used Health Haeards. The prindpal hazard associated with epoxy resin systems is a skin reaction or dermatitis. Epoxy resin dermatitis is largely due to curing agents and solvents. The condition is simply irrita tion or allergic reaction of skin rather than a general systemic toxidty. Amine com pounds, add anhydrides, organic adds, and organic peroxides which are used as curing agents are both primary irritants and skin sensitizers. Probably the most troublesome of the chemicals are amine catalysts. Skin contact with these curing agents is responsible for the majority of dermatitis cases associated with epoxy resin systems. The completely cured epoxy resins are rela tively inert and do not constitute a derma titis exposure. However, dermatitis cases are common among workers machining or cutting resins thought to be cured, but which still contain free catalysts, Amine vapors, which are usually abundantly liberated during hot curing processes, cause irritation of the eyes and mucous membranes. In some individuals, they also can cause a lung reaction resem bling asthma. These vapors may cause der matitis among sensitized workers. Exposure to dust from fillers such as silica flour, asbestos, and diatomaccous earth may present potential health hazards. Fiberglas, which Is used in laminating operations, can cause irritation to the skin, eyes, and mucous membranes. Dust resulting from cutting, grinding, and shaping of completely cured resins is relatively inert If an excess of curing agent is present in the resin, the cured product may contain unreacted curing agents whicn present a dermatitis exposure. Explosion Hatards. Most uncured epoxy resins have flash points above 300F and do not present a serious fire hazard. Some diluents, curing agents, and solvents toed with epoxy resin systems are flammable. The fire and explosion hazards associated with epoxy resin systems are normally con sidered to be slight. First Aid. If skin contact with unreacted epoxy resin system components occurs, af fected areas should immediately be thor oughly washed with a mild soap and water. If eye contact occurs, wash for at least 15 minutes and refer to a physician. Preplacement Medical Procedures. Work ers with a history of skin diseases, allergies or abnormal pulmonary conditions. should not be employed in areas where epoxy resin materials are used. Health Hasard Control Methods. 1. Good general ventilation is necessary for areas using epoxy resin systems. Local exhaust ventilation may be needed at mixing stations and curing areas, especially if large quantities of materials are involved. Curing ovens should be exhausted to the outride. 2. Adequate wash facilities should be pro vided in the area where epoxy resin systems are used. An ample supply of mild Boap and disposable towels should be provided- 3. If possible, areas using epoxy resin systems should be isolated from other areas of the plant 4. Good housekeeping is essential All spills should be cleaned immediately. The use of disposable paper overbp on work areas is desirable. Contaminated paper should be removed and stored in covered metal containers. The scrap should be removed from the plant daily. 5. All gloves or tools contaminated with epoxy resin components should be washed in a suitable solvent such as acetone or alcohol, followed by soap and water. 6. Workers should be thoroughly in structed in proper handling techniques for epoxy, resin systems, be acquainted with potential hazards, and have dose supervision. Personal Protection. 1. Rubber or plastic gloves (preferably cotton lined) or disposable surgical gloves and arm protection should be worn where 8 Occupational Health Nwmg Committee skin contact !b possible. After use and before removal from the hands, the gloves should be washed in solvents (acetone or alcohols), followed by a water rinse. Before re-use, gloves shohld be inspected for leaks. 2. The use of eye protection, aprons, or uniforms may be indicated if this is a po tential splashing hazard. 3. Smoking should be prohibited. 4. If skin contamination cannot be re moved with a mild soap and water, small areas of the skin may be washed with ace tone or alcohols, followed by washing with mild soap and water. Petroleum solvents should not be used to clean the skin. 5. Barrier type protective creams have been used with success for dermatitis control in many plants. However, they are not in tended to be a substitute for protective clothing or good personal hygiene. X-Radiation At this point I would like to take you into the controversial field of x-radiation from TV sets. This is a medical engineering problem; one that has occupied the attention of the medical department over the past many years. It is necessary at this time to separate the facts from fiction and the fantastic. Man pollutes his world gradually, almost imperceptibly, and in many different ways. One of the least obtrusive ways he has yet invented is the introduction of man-made radiation into the environment Attention was called dramatically to that land of pollution last year (jjfcen a major TV pro ducer placed on the market more than 100,000 TV sets suspected of emitting x-rays. It is a fact that color sets require higher voltage than black-and-white and are capable of producing some x-radiation. In the case of the aforementioned sets, the problem had to do with a shunt regulator tube which regulates the high electron voltage to the picture tube. Due to engineering error, this tube was poorly shielded and mounted in a position which permitted x-rays to escape from the set Further investigation with other manufacturers' sets revealed that dif ferent kinds of design or servicing problems could account for defective control of color TV x-radiation. TV <-set x-radiation can be thoroughly controlled by proper shielding, set design, and monitoring levels at time of manufac ture. The level of radiation from the vast majority of defective sets u identified by the United States Public Health Service represented no known risk to the health of viewers, though b a few cases there were high levels of excessive radiation--as high as 25 or more times the accepted limits. The main concern was over possible harm to descendants of the viewers, but even that seemed highly improbable: It is the medical departments responsibility, in cooperation with the engineers, to keep radiation from TV sets at the proper level This level can easily be maintained below 0i5 milliroentgen per hour, the limit accepted by science, government, and industry as prudent in a world where man is adding significantly to the radiation dose bequeathed by nature. TV set producers are now providing con sumer and technician-proof sets incapable of producing excessive radiation despite the most flagrant tampering. However, the prob lems of x-radiation still exist in the manu facturing and testing area, and therefore require constant monitoring, medical engi neering supervision, and controL We have demonstrated that a properly constructed color TV set offers no health, hazard what soever. The following letter, authorized by a com petent medical authority, is for the edifica tion of our customers and available for general public bformatioo: ' "Color and black-and-white television sets manufactured by Syhrama Electric Products, Inc., G.TAR, more than satisfy all the safety requirements of the National Council of Radiation Protection Measurements, as well as those of the International Commis sion on Radiological Protection." Sylvania subjects its television production lines to exacting scientific tests for emission of x-radiation. In addition, we periodically employ outside scientists to make independ ent tests of our sets, both in the plant and after they have left the factories. These tests employ stringent government-accepted and industry-accepted methods of measurement. Constantly, our engineers conduct tests for x-radiation on oar color television sets in production and as consumer products. All tests showed that in more than rune out of ten instances the Sylvania sets showed no detectable x-radiation whatsoever. The only reading in these tests was the background 9 1968 National Safely Congress level of radiation normally present in the atmosphere. Even in the very few sets where an actual radiation reading was detected, the level of radiation was well within the ac ceptable levels established by government and quasi-government bodies. In other words, Sylvania television sets are safe. We shall make certain that sets we produce in the future also will be safe. In conclusion, I trust we have briefly summarized some of the major medical aspects and safety problems peculiar to the electronics industry. There are others, to be sure, such as control of cadmium, the gen eral overall control of plant effluents, etc., but we must necessarily limit our discussion to the major and newer toxicological prob lems; establishing die facts, and discarding the fiction, along with die sometimes fan tastic misconceptions. ' THE ROLE OF THE INDUSTRIAL NURSE IN THE ELECTRONIC AND ELECTRICAL EQUIPMENT INDUSTRY By PATRICIA M. TUOHEY, R.N. Health Consultant, Loss Prevention Medical, Liberty Mutual Ins. Co., New York, N. Y. To those who represent the electronic and electrical equipment industries and who ex pect to hear magic words just for them alone, I apologize. I know of none.; The problems of industry are people -- all people -- not so much the exposures, nor the en vironments, but the people who work in those exposures and environments. To handle the people we need a good medi cal program. To handle the medical program we need a good industrial nurse. To have a good industrial nurse we must understand what her role should be. Let us discuss some of the industrial nurse's major functions. Nursing Care Care for occupational and non-occupa-' donal injuries and illnesses will always be a major function of the industrial nurse. She has a responsibility to initiate prompt and skillful emergency care, consistent with her professional training and knowledge of first aid techniques, until the services of a phy sician can be obtained. The nurse's interest in and concern for the welfare of the ill or injured combined with prompt attention, good judgment, and sound management can be a step toward prompt and uneventful rehabilitation. The nature and extent of the nursing care provided for non-occupational injuries and illnesses should be determined by the com pany physician. Generally accepted practice allows for the simple (palliative) treatment of minor complaints that arc not expected to require the services of a physician. The more serious ills that merit medical attention should be referred to the family physician. In addition to her technical skills, the nurse should recognize the possibility that each visit to the health service may repre sent a problem of deeper significance titan the symptom for which attention is being sought The so-called "chronic complainer,'1' the employee who suffers frequent minor injuries, or even the daily visitor to the scale may well be an individual crying for help. Careful listeping on the part of the nurse may help to uncover an underlying emotional problem and avoid a major tragedy. For this reason, enlightened management has learned not to discourage non-occupational visits to the medical department no matter how simple the complaint. Medical Examinations Medical examinations are an important component of a sound occupational health program. Their value as an aid in providing criteria for safe job placement in uncover ing early physical and emotional changes, and in detecting the effects of harmful work ing conditions contributes to the maintenance of a safe, healthy and productive employee population. The plant nurse becomes an ac tive participant in the company examination program as she conducts the health interview and performs the preliminary evaluations 10 '