Industrial Hygienists Discuss Radiation Hazards A STAFF REPORT JLiVER broadening its base of the professions and fields of application with which it is concerned, the American Industrial Hygiene Association held its ninth annual meeting at Boston's Hotel Statler, March 30 to April 1. Its extension into these fields was reflected in the attendance of o v e r 600 industrial hygienists from all p a r t s of the country who gathered to a t t e n d and w i t h the specially interesting symposia on radiation hazards in industry, industrial toxicology, and heat exposure. T h e audience was extremely varied in its basic training and included physicians, physiologists, chemists, chemical engineers, physicists, a n d electrical and mechanical engineers. In t h e words of its president, T . F . H a t c h of t h e Industrial Hygiene Foundation, this ramified membership meets agreement with that definition of industry as " t h e proper blending of men, materials, and machines into a profitable, productive relationship with a minimum of wear, waste, and weariness." T h i s meeting of the A H I A , which was held in conjunction with the annual meetings of four other industrial health groups and a n exposition of equipment and drugs used in industrial health practice, reached its climax with t h e presentation of t h e annual Donald Cummings Memorial Lecture by Alice Hamilton of the H a r v a r d Medical School. D r . Hamilton, long renowned as America's foremost woman industrial hygienist, was the first woman on t h e facult}* of Harvard Medical School, the only woman to serve on t h e Health Committee ©f the League of Nations, and t h e author of several books on industrial toxicology. H e r contributions in the investigation a n d prevent ion of industrial lead, mercury, a n d phosphorus poisoning have received considerable attention and her work has been largely responsible for t h e safety techniques now employed in their use. D r . Hamilton named t h e Cummings Lecture she presented as a summation of " F o r t y Years in t h e Poisonous T r a d e s . " I n it, she reviewed t h e growth of industrial medicine, which was not recognized in this country as a branch of legitimate medicine until World War I when a shortage in manpower made t h e protection of industrial workers against industrial sickness important. I n these "few" years, Dr. Hamilton continued, we have passed from "the kindergarten to the postgraduate college" and now lead the world i n industrial hygiene research. This h a s been directly responsible for our abilit i e s to s u b s t i t u t e safe substances for poisons a n d acquire significant d a t a on t h e maximum allowable concentrations of toxic fumes, dusts, and gases. T h e
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developments of industrial chemists,* however, the speaker continued, have presented us with new problems. Welding is replacing rivetting, steel alloys now have greater contents of manganese, vanadium, cadmium, a n d beryllium, and some more familiar poisons such a s lead, mercury, and phosphorus are being used in heretofore unexpected places. Synthetic rubber requires compounds which t h e rubber industry has never used before a n d "the list of organic solvents continues to grow and present more a n d more complicated problems to the industrial hygienist. Radiation Hazards in Industry I n response t o the increasing demand for more information about the hazards of radiation in industry, a symposium on this subject was presented by a group of health physicists who have joined with the AIHA recently. Under the chairmanship of James H . Sterner, of t h e Eastman Kodak Co. and the incoming president of the AIHA, t h e symposium presented a program of four papers t h a t culminated in the presentation of an extensive treatise by K. Z. Morgan of the Oak Ridge National Laboratories entitled "Protection against Radiation Hazards and Maximum Allowable Exposure Values." D r . Morgan revealed that the first case of radiation exposure recorded occurred only one year after the discovery of x-rays and was followed by frequent cases of death and suffering due mainly to igJ. W. Healy, Hanford Engineer Works, holds pen-shaped ionization gages which he exhibited during the symposium on radiation hazards
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norance and carelessness in handling the dangerous radiation. T h e lessons taught by these sacrifices, D r . Morgan claimed, made the scientists involved with the a t o m i c energy project safety conscious and although they were determined to push their work forward, t h e y did so along cautious lines t h a t resulted in a splendid safety record. A good deal of the credit for this achievement, the speaker claimed, is due t o the work of t h e health physics division, which was organized in t h e summer of 1942. Among its first" tasks was t h e determination of the tolerance dose of radiation exposure, t h e difficulty of which was intensified by the consideration of the variation of radiosensitivity among individuals, the dependence of tolerance dose upon the energy of t h e radiation, a n d the relative damage of local bod}- exposure and t o t a l body exposure to radiation. I t afterwards proved fortunate t h a t 0.1 roentgen per day was accepted a s t h e tolerance dose, D r . Morgan continued, for although subsequent d a t a have shown t h a t biological a n d genetic changes do take place at t h i s level, there is considerable reason to believe t h a t this rate of exposure m a y be continued for y e a r s without causing perceptible biological damage. Recent experiments b y Lorenz with mice have shown t h a t ovarian t u m o r s were induced when a minimum t o t a l dose of 100 roentgens was accumulated a n d t h a t a single dose of 50 roentgens given in 4.5 hours increased the incidence of such tumors. "For this reason, Lorenz suggested in 1946 t h a t the total accumulated exposure should not exceed 100 roentgens t o females a n d 1,0.00 roentgens for males. I n the light of these developments, D r . Morgan continued, the tolerance level of 0.1 roentgens per day chosen five years ago for t h e plutonium projects is n o t as low as it should be. F o r t u n a t e l y , however, t h e health physicists were conservative, h e said, a n d h a d modified t h i s level b y applying a safety factor of 10 from t h e very beginning of t h e project a n d considered t h e 0.1 roentgen per d a y dose as a maximum permissible dose of radiation. Pen-shaped ionization chambers • were worn b y the shift workers at a t o m i c energy plants, a n d t h e readings made o n such instruments a t shift change would indicate t h e dosage received during t h e working hours. Whenever the tolerance level has been reached, the worker receives notification before the next shift to p r e v e n t repetition of the exposure. Other functions of the health physics division include t h e checking of water a n d air discharged from the p l u t o n i u m
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E. C. Barnes of Westinghouse Electric Co., president-elect of Industrial Hygiene Association; T. F. Hatch, Industrial Hygiene Foundation, retiring president of AIHA; and J, H, Sterner, Easttnan Kodak Co., netv president of AIHA projects to make certain that the concentration of radioisotopes does not at any time reach tolerance level. Monitoring of working areas and equipment is also maintained by the use of suitable radiation detection instruments. Protective devices are constantly checked for working emcienc\'' and state of repair. In addition to these duties, Dr. Morgan concluded, the health physics division must carry on an educational program to prevent the insidious damage of radiation. Dr. Morgan's paper was preceded on the program by a talk on "Radiation Measurements in Health Physics," in which the author, J. W. Healy of the Hanford Engineer Works, explained some of the instruments for radiation detection to which Morgan subsequently referred. Healy pointed out that the health physicist is primarily interested in that fraction of radiation that is absorbed by tissue and which may cause damage. Since this is a difficult quantity to measure directly, the energy absorbed in air, as measured by the ionization produced, is chosen as ix unit of radiation dose. This is the modus operandi of the ionization chambers worn by the workers. The evaluation of this personal exposure is performed after the principal source of radiation has been tracked down through the use of Geiger-Muller counters. The theory and pathology of carbon disulfide poisoning came in for review in the symposium on industrial toxicology. Heinrich Brieger, R. H. De Meio, and M. H. F. Friedman of the Jefferson Medical College declared that in general the typical clinical signs of carbon disulfide poisoning are well known and for the most part the hazards can be controlled by adequate engineering design. The developmental mechanism of the poisoning is still unknown. The authors believed that there is to date no proof that carbon disulfide is a true blood poison or that anemia is a regular sign of carbon disulfide V O L U M E
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poisoning. In spite of this European publications are again reporting such results, results with which the authors of this paper cannot agree Brieger and his associates claimed that they have examined the bone marrow of rabbits exposed to excessively high concentrations of carbon disulfide and observed no significant changes. Electrocardiograms of rabbits so exposed were also studied and contrary to previously published conclusions they were unable to find any evidence of the influence of carbon disulfide in the cardiograms. Conclusions in the study of the industrial toxicity of dimethyl chloroethylaminc and diethyl chloroethylamine were presented in the paper by R. M. Watrous, J. K. Martins, and H. Schulz of the Abbott Laboratories. I t was found that exposure to \,he vapor of the ethyl compound caused irritation of the mucous membranes of the eyes, nose, and throat, and that exposure to the methyl compound caused immediate nausea followed some hours later by vomiting and prolonged dilation of the pupils. No effect was observed on the circulatory system and no destruction of the leucocytes was observed. The paper tentatively suggested that levels of the methyl compound in excess of 25 micrograms per liter would cause toxic sjonptoms if breathed for eight hours. Ketene Exposure J. F. Treon and his associates at the Kettering Laboratory of Applied Physiology at the University of Cincinnati revealed some of the data obtained from their investigations into the physiological response of animals t o respiratory exposure to ketene. Because it is a valuable acetylating agent, this compound is being employed increasingly in the manufacture of organic chemicals. In the experiments described in the paper differences in mortalities appeared beAPRIL
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1948
tween species when exposed to ketene. The results showed an increasing amount of resistance to the poison in the order: mouse, monkey, rat, guinea pig, cat, and rabbit. In dynamic experiments conducted for longer periods ketene was found to resemble phosgene in its action on the respiratory system. A second paper by Treon and associates presented data gained from similar exposure experiments on animals using diisopropylamine. There is a considerable dearth of information on the nausea and impairment of vision effects of this compound on workers, the authors revealed. It was found in the animal experiments that diisopropylamine is an alkaline irritant to the mucous membranes and when inhaled in sufficient concentrations it produces pulmonary congestion and edema. Direct contact of the material in a vapor state with the eyes of the animals resulted in a temporary turbidity of the cornea. Toxic effects of the vapor inhaled gave the following mortality result in decreasing order of susceptibility: rabbit, guinea pig, rat, and cat. E. J. Largent and F . F. Heyroth, also of the Kettering Laboratory, discussed their studies on the absorption and excretion of fluorides, in which they sought to answer some of the questions arising about the metabolism of fluoride in the human body. Many of the queries, the author pointed out, have been instigated by the use of fluorides by certain communities in the drinking water in an effort to curb t h e incidence of dental caries. In the work described, fluoride in both, soluble and insoluble states was fed to an experimental subject. It was found that 93 to 98% of the soluble material was absorbed by the body as compared with 62 to 7 7 % of the insoluble substance. In additional work, urinalyses were run on 23 selected workmen engaged in two factories in the manufacture oi inorganic fluorides. Fifteen of these men excreted fluoride at concentrations of 0.5 to 6.0 milligrams per liter. On the other end of the distribution curve, one man was found who excreted 4.8 to 28.4 mg. per liter. Sixteen of the 23 were given roent^ genographie examinations with only one showing a marked increase in bone density, one a moderate increase, and two a slight increase. Nfo disability or evidence of injury -was detected in connection with the changes noticed. The old controversy over the use of maximum allowable concentration levels opened briefly in the paper by II. B. Elkins of t h e Division of Occupational Hygiene of Boston, Mass. The author revealed t h a t in spite-of the popularity of the use of these criteria, arguments have arisen tliat more stress should be laid on engineering and medical aspects. He concluded "that more and not less emphasis should be placed on the use of maximum allowable concentration values. 1075
