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Occupational health study of Midwestern formula feed mills.

Gibson RL; Longley MY
Cincinnati, OH: U.S. Department of Health, Education and Welfare, Public Health Service, Division of Occupational Health, RR-1, 1962 Sep; :1-77
Three Midwestern formula feed mills were surveyed for the existence of occupational health problems. Although there were operational differences in the mills visited in other sections of the country it is felt that the Midwestern mills which were included in the survey illustrated the potential health hazards of the industry. Environmental samples and observations of production methods indicated that, during the period of this survey, exposures in excess of specific recommended threshold limits for compounds used as an index of overall environmental exposure did, on occasion, occur. However, due to the intermittent nature of operations and a wide variety of formulations successively processed during the study, the average daily atmospheric concentrations for the compounds used as indices of exposure were generally within suggested limits. There was no doubt though, that the overall dust levels were very high at many operations. The findings give no room for complacency since the compounds selected for study may not have been representative of the hazardous nature of the environment. These statements are based on the present knowledge of the materials found in animal feeds. In many cases this knowledge is rather limited; this is especially true in the case of low level, long term exposure to most of the additives. Changes in process or in quantity and type of feed additives could result in hazardous exposures. Even with currently used materials and processes, such factors as poor ventilation, poor personal hygiene, and with handling methods which generate airborne dust were observed in various mills and could result in occupational health problems. Medical examinations were made on 116 feed mill production workers and 23 office workers. The findings were essentially negative. The prevalence of non-occupational disease appeared to be comparable to that reported in medical studies of other industrial populations. Occupational disease was not found in the production group of workers participating in the survey. Chest roentgenograms and pulmonary function tests did not furnish evidence of pneumoconiosis. Occupational dermatitis was not confirmed by physical examination although several workers had reported skin problems following contact with various feed ingredients. Clinical evidence of chemical intoxication was not disclosed by the medical and laboratory examinations. In addition, urine analyses for arsenic, cobalt, diethylstilbestrol (DES), copper, manganese and zinc failed to reveal excessive excretion of these materials. Although the medical findings with respect to well-defined occupational disease were negative at the time of the survey, caution should be exercised in applying these data to the industry. Selectivity may have had an Influence on the findings since the group examined were, at the time, employed in the industry. Workers who could not satisfactorily adjust to the mill environment may have left the industry. Information was not available either on this group or on those who had retired after working a lifetime in the industry. Many of the potentially hazardous materials in the mill environment have been in use for relatively short periods of time and may have unestablished additive and synergistic effects on the workers. In addition, a large proportion (78%) of the feed mill employees participating in the survey had worked less than 10 years in the formula feeds industry. The effects, if any, of low level exposures might not be evident within this period. Further observation of the workers would be necessary to completely define the importance of this time factor.
Feeding-study; Dust-exposure; Dust-inhalation; Particulate-dust; Particulates; Respiratory-hypersensitivity; Respiratory-irritants; Respiratory-system-disorders; Pulmonary-disorders; Pulmonary-function; Pulmonary-system; Pulmonary-system-disorders; Skin-exposure; Skin-irritants; Skin-sensitivity; Workers; Worker-health; Work-environment; Humans; Men; Women; Carcinogens; Fungi; Environmental-exposure; Risk-factors; Exposure-levels; Exposure-limits
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Division of Occupational Health
Page last reviewed: March 18, 2022
Content source: National Institute for Occupational Safety and Health Education and Information Division