Document ExxB5q5pDd5YrRL2GkyMMrzvR

FILE NAME: DuPont (DUP) DATE: 1935 Dec DOC#: DUP174 DOCUMENT DESCRIPTION: Journal Article - Chemical & Metallurgical Engineering \/\/y v ^ l/\n s^ Industrial M edicine and Toxicology ment of | occupational diseases when they occur, i s ? w j nd symPt0"s h> be expected. `." '.5 l" " * d w* j ;L 'M .?eTM 7 ,, u" d.'h Stood and proper methods of handling instituted. M ? L N T h/ dt n demands that we improve anH rtiprf K d i ethods hy whlch workmen were made ill i ni d ed b/ the score> that we devise adequate methods of preventing occupational poisonings 4 and neerJ T j T J er? f.ore' 14 ls necessary that chemical engi- riamH d Physicif ns shuld become more closely asso ciated in order to develop sufficient knowledge concerning these health hazards, and with this knowledge to in s S t?onsPsTfeCtlVe meaSUrCS which wil1 make a11 Plant opera Industrial medicine is not a new specialty ; neither is the recognition of occupational diseases of recent origim Bernardini Ramazmi, during the 17th century, wrote a treatise on the diseases of tradesmen, in which heRecog nized many diseases of occupational origin. He defined mdustnal medicine when he said, " We must own that some arts entail no small mischiefs upon the respective artisans, and that the same means by which they support this damage is progressive and incurable. There arc industrial diseases that are sudden in onset and tenui nate in death m a few hours; in this class we have chlorine poisoning, which causes an acute respiratoiy disease. There are acute occupational diseases which appear almost immediately after exposure, run an acule course for a period of 12 to 48 hours, and clear up in a few days. Aniline and nitrobenzol are examples of sub stances which cause this type of illness by their action upon the red blood cells, forming methemoglobin, which is followed by the destruction of many millions of the cells. These and other examples of industrial intoxica tions have developed with the progress of industry and have been recognized as the result of bitter human ex periences, inestimable suffering and often death. Industry must realize that the previous methods of trial and error are no longer acceptable, neither are they 1 fe and maintain their families are oftentimes the cause worfd " V r dlStemP f s which hurry them out of the world. < Compare the simple industrial operations of Ramazmi s time with the complex operations and toxic substances of today and it is obvious that we are facing a comphcted problem that must be worked out by the chmcian and the toxicologist, as well as the engineer. What is industrial medicine and how may it be suc cessfully applied? It is not simply the treatment of occupational diseases and intoxications, but includes that which is more important--medical methods for the pre vention of these diseases. P Occupational diseases occur as a result of exposure to SboormneeSUoff SthresCeeSd^isnedasleasCkaref tPhre preersumltesdiocfalyseuaprservoifsioenx, posure disease amndwhciacnhnoctlmbiecalcusryemdp; tofmors example, silicosis a do not appear until there has been extensive lung damage. Unfortunately, eddgSe noff Cnh'ealntuhmuhhazear'rd7s \bnemfoSrte doepveerlaPtioancscuarraete sktanrotwed!-, Operative procedures must be designed to prevent toxic exposure, and industrial health must have adequate med ical protection. H The toxicologist, by proper methods of animal study can develop the toxicity of a compound and the mecli- holhffi ltS aCtl-n- F r m these facts he can P int out n V 7 f h Caf 10nS, necessary for safe operation in the plant and the clinical symptoms which indicate the begin n i n g ^ poisoning. With this information the industrial physician can establish adequate methods of medical supervision, organized on three basic principles; viz proper selection of all employees, special medical pro- chseasesexaminatlons' and treatment of occupational Pre-employment physical examination is the only means of making the proper selection of employees. The EnSgineierrs. H ws 91 tne Ameri<=an Institute of Chemical fartnrf T i!hlS examination is dependent upon several k n lrt h T t " * er must have at least a reasonable knowledge of the working conditions of the plant and the physical and mental requirements of the individual 672 CHEMICAL & METALLURGICAL ENCINEERINC--Vol.42,No.l By G. H. GEHRMANN, M.D., F.A.C.P. Medical Director, E. I. duPont de Nemours & Co., Wilmington, Delaware. M ake for Safer Plant Operation Du Pont company executives in the Toxicological room of the Haskell Laboratory of Industrial Toxicology. From left to right: W illiam Deichmann-Crueber, assistant to Dr. W . F. von Oettingen; Ernest B. Benger, assistant chemical director; Dr. A . P. Tanberg, director of the Experimental Station; C. C. Ahlum and E. F. Hitch, of the company's Jackson Lab oratory at Deepwater Point, N. J .; Dr. W . F. von Oettingen, director of the Haskell Laboratory; Lammot du Pont, president; and Dr. G. H. Gehrmann, medical director. jobs. Job requirements have a wide range of variation. For example, the physical effort necessary safely and effi ciently to perform duties may range from physical per fection of 100 per cent down to a very low percentage. The worker who is engaged in lifting heavy materials all day must possess more physical ability than one who maintains temperature and pressure regulations in a chemical operation. Furthermore, the worker who pos sesses the physical strength to perform laborious work all day may not have the mental requirements that would make him an efficient chemical plant operator. There are many compounds used in industry which i are toxic and under certain conditions may cause sudden death; examples of these are H C N and H 2S. The latter in high concentrations kills almost instantly and, further, these high concentrations cause rapid paralysis of the olefactory nerve with a complete loss of the sense of smell. Therefore, it is possible to walk unaware into a high concentration of H 2S, become unconscious, and die before rescue is possible. Concentrations above 500 parts per million are dangerous. Other compounds are toxic to a lesser degree, act more slew ly and produce chronic disease-- some in a short time and others after years of exposure. Lead is an example of the former. Lead gives rise to acute symp toms, depending upon the amount of the daily exposure, in a few days or a few weeks. Then, as examples of those compounds which require years to act are certain nitro- and amino-compounds which cause simple tumors and cancers of the urinary bladder after an average ex posure of eleven years. _ _ . Some compounds have a selective action upon certain organs. Carbon tetrachloride interferes with the func tion of the heart muscle. This action is more severe when the heart muscle is affected by heart diseases. Therefore, an individual with a normal heart muscle may successfully withstand the effects of this substance, but one with a diseased heart muscle may die with acute cardiac failure. _ Mercury compounds are eliminated through the kid neys and cause severe irritation with acute or chronic nephritis. Phosgene, nitrous fumes and other irritant gases cause marked inflammation of the lungs and may aggravate a more active pulmonary tuberculosis. Any chronic lung disease may be aggravated to such a degree as to cause acute illness, permanent disability, or death. Organic disturbances of the central nervous system may be aggravated by such compounds as carbon bisulphide and those of lead. Lead intoxication produces an en cephalitis, which is almost impossible to differentiate from the mental disease produced by late syphilis. These are some of the possibilities which must be con sidered by an examiner in order that he may protect an applicant, who has an already established disease, from December, 1935-- CHEMICAL & METALLURGICAL ENGINEERING 673 working with compounds that will aggravate or activate his condition. In 1911, the first compensation laws were passed in this country. Prior to this time there were, to the best of my knowledge, no physical examinations in industrial plants. The passage of these laws made industry respon sible for accidents and physical disabilities, and the phys ical examination was introduced as a protection against claims for conditions that existed before employment. At that time applicants were refused employment for even minor physical defects. Later, the compensation laws were amended to include occupational diseases as well as injuries. This necessitated a more complete em ployment examination and developed the periodic exam ination as a method of detecting the beginning symptoms of occupational diseases. Experience indicated that respiratory diseases were being frequently missed, the errors in diagnosis being reflected in the incidence of activated lung processes occurring after exposure to irri tant gases. Kidney damage was, in a like manner, being overlooked, and cardiac and circulatory pathology either missed entirely or the findings not given the proper inter pretations. costs comparatively little money, does not supply a*|< quate information or protection, gives a false feeling ..f security and, in truth, is wasted time, money and ell mi All too frequently the physicians making these exam inn tions have little or no knowledge of factory condition, job requirements, and health hazards that exist. Selection is the first step toward the successful appli cation of industrial medicine and the second is adequate protection. Adequate protection is provided by uvn means---properly designed operative, protective measim- and equipment, and periodic medical examinations. I'm tective equipment is an engineering problem that should never be planned until the toxicologist has pointed oui all the health hazards that may exist, and before he nm do this he must make a careful toxicological study, which should be completed while prospective operations are in the experimental stages. By the time they have reached the semi-works, it is usually too late because the equip ment for production has been selected. In the past, many chemical engineers have assumed that because they have been able, or more frequent h fortunate enough, to work through the experiment! stages of a project without any visible damage to them Purpose of Physical Examination There then came the realization that physical exami nations for industry should be of such a nature as to accomplish two purposes: First, to select applicants and place them in occupations that would not aggravate any existing disease; second, to eliminate the unnecessary exclusion of applicants who, although they presented cer tain physical defects, were nevertheless able, safely and efficiently to fill properly selected jobs. In order to ac complish these purposes we realized that we must have more accurate diagnosis at the time of employment. A medical diagnosis is made by combining what the patient tells the doctor with the findings as observed by the doctor. Both factors are extremely significant and probably of equal importance. Patients present them selves to their personal physician to be cured of an illness and naturally tell of all'their complaints. On the other hand, applicants for employment present themselves to the examiner with hopes of passing their examinations and, therefore, have an incentive to cover up any existing illness and conceal many pertinent facts concerning their medical history. This places the examiner at a disad vantage, and so in order to detect lung pathology, liver disfunction, nephritis, cardiac diseases, circulatory dis turbances and central nervous involvement, he must have at his command all the modern diagnostic equipment for making: urine analyses, blood examinations (including blood chemistry), blood counts, serum examination for selves, the compound at hand was non-toxic. This a sumption is frequently erroneous since it is possible In have degenerative processes started in certain organ without visible or clinical evidence. F or example, de generative process in the liver may be very extensive before there is any clinical evidence. Therefore, it is n decided advantage, both from the health and econonm viewpoints, to know how to start new operations with safety. There are today many operations which should be improved. Some can be made safe with reasonable changes; others will require a complete change of operai ing equipment. The question may well be asked, " Why do we need periodic medical examinations if our factories are equipped with operative devices that eliminate exposme to health hazards?" My answer i s : First, I have yet to see the mechanical equipment, no matter how per feel, that will continue to remain so, and very often the find knowledge of its faulty function is the appearance oi toxic phenomena in the employees. Secondly, there fre quently _arise new sources of contamination, sometime from within the operation and sometimes from without Thirdly, the human flesh is heir to many ills, some devel oping slowly, others rapidly, many insidiously. There are many chronic ailments that are never suspected unlit far advanced. Many of these can be detected early and at least improved by removing the individual from anv source of possible toxic irritation. syphilis, X-ray films of the chest and, in special cases, electrocardiograms and basal metabolism tests. Frequency of Periodic Examination _Unfortunately, there are too many industries today giving little or no consideration to such an examination and many others making no examination at all. They consider this work unnecessary as long as their insurance carriers give them adequate coverage. Many are una ware of the hazards that exist in their factories, others show no interest until they are forced to become inter ested, either because of compensation experiences, civil suits, or insurance rates that have increased to such an extent as to be reflected in higher production costs. Too many are satisfied with a superficial examination which The frequency of periodic examinations should be determined by the toxicity of the compound involved and the rapidity with which it may enter and attack the human body. Lead, for example, may produce symp toms in a few days or it may take years, depending upon the atmospheric concentrations. Benzol may cause chronic poisoning in a few days and I consider monthfy examinations necessary in both lead and benzol opera' tions. Nitro- and amino-compounds are all more or less toxic and workers in these compounds should have an examination at least every three months. Chemical plant 674 CHEMICAL & METALLURGICAL ENGINEERING-- Vol.42,No.l? workers who are not exposed to any known hazards should be examined once a year. Periodic examination should be designed to bring out the physical signs and symptoms to be expected with the exposure to certain substances and need not necessarily include a general physical examination. Beta naphthyl'amine, alpha naphthylamine and benzidine, for example, cause tumors of the urinary bladder, and in so far as we know, do not affect other organs. Therefore, it is only essential to make a careful search for these tumors. Ben zol, by its action upon the blood-forming elements causes a primary anemia which can be detected by certain blood examinations. Thus, the entire field of periodic exami nations should be based upon the clinical signs to be expected. Here again the toxicological study of a com pound makes it possible to design a type of examination that will reveal to the clinician the evidence of beginning organic changes within the body. The appearance of clinical evidence of intoxication in a well-controlled operation may mean either a failure of proper function in the equipment or a careless work man who is not following the rules of hygienic control. Faulty equipment is usually reflected in a group of em ployees; disobedience to rules and regulations in single individuals. In either event, the evidence indicates that employees are being poisoned, and the source of contami nation should be corrected. The correction of faulty operative conditions is necessarily an engineering prob lem. The matter of proper handling of an individual who is showing signs of toxic absorption is entirely med ical and in each individual case the physician must decide whether it is safe for the employee to continue in his operation or whether he must be removed from source of further intoxication and given special treatment. Industrial toxicology offers the means of avoiding fre quent repetition of our past experiences of human su f fering, acute illness, chronic illness and death. With the aid of the toxicologist and the pathologist, we can elimi nate from our industries occupational diseases and toxic processes. We can start all new operations with ade quate protective measures and a scientific understanding of the toxic symptoms to expect, based upon our knowl edge of the mechanism of their production. The toxicity of a compound may vary with the condi tions under which it is used. Substances which give little or no trouble at ordinary temperatures become extremely toxic at higher temperatures; some substances decompose and give off poisonous products when heated. Carbon tetrachloride brought into contact with hot metal or an open flame is oxidized and phosgene is liberated, which has a destructive action on lung tissue. In order fully to understand the toxicity of a compound, we must know how the material is handled, the temperatures to which it will be subjected, physical changes in the operation, the various conditions under which it will be handled and the possible chemical changes which may occur. There must be a very careful study of the effect of a compound upon the body organs. What does it do? How does it do it ? What organs of the body are affected and what clinical symptoms are to be expected as the result of intoxication? There are certain substances which produce disease mechanically and in themselves are not poisonous. Silica dust is an excellent example of this type of material. Fine silica dust when inhaled eventually becomes imbedded in the lung tissues, setting up an irritation which is followed by the formation of fibrous tissues. The physical characteristics of the lung change. It loses its elasticity and its function is inter fered with, depending upon the stage of the disease. This is the disease known as silicosis. Silicosis is chronic, progressive, incurable and often leads to total and per manent disability. When complicated with tuberculosis it is usually fatal. The subject of toxicology requires the development of an extensive amount of knowledge, otherwise its ap plication to industry is of no practical value. Haskell Laboratory of Industrial Toxicology, a new medical research laboratory of the du Pont company, which has been erected on the grounds of the company's Experimental Station near Wilmington, Del. December, 1935-- CHEMICAL & METALLURGICAL ENGINEERING 675