1、Effects of Welding on Health IEffects of Welding on Health A literature survey and evaluation to establish the state-of-the-art and to point the directions for future research to understand and improve the occupational health of welding personnel Research performed at the Franklin Research Center un
2、der contract with the American Welding Society and supported by industry contributions Prepared for: SAFETY AND HEALTH COMMITTEE AMERICAN WELDING SOCIETY 550 N.W. LeJeune Road, Miami, Florida 33126Library of Congress Number: 79-52672 International Standard Book Number: 0-87171-180-X American Welding
3、 Society, 550 N.W. LeJeune Road, Miami, FL 33126 1979 by American Welding Society. All rights reserved. Note: By publication of this specification the American Welding Society does not insure anyone utilizing the specifica- tion against liability arising from the use of such specification. A publica
4、tion of a specification by the American Welding Society does not carry with it any right to make, use, or sell any patented items. Each prospective user should make an independent investigation. Printed in the United States of AmericaContents Personnel vii Acknowledgments ix Preface xi Introduction
5、xiii Executive Summary xv Technical Summary xvii Recommendations xxi /. The Exposure 1 Fumes 1 Gases 3 Radiation 4 Noise 4 Other Factors 4 2. Effects of Welding on Health 5 Respiratory Tract 5 Acute Diseases due to Occupational Exposure 5 General Acute Respiratory Disease in Welders 7 Siderosis and
6、Mixed-Dust Pneumoconiosis 7 Chronic Respiratory Conditions 12 Serum Enzymes 22 Carcinogenicity 22 General Cancer Mortality 22 Lung Cancer 22 Digestive Tract Cancer 24 Skin Cancer 24 Eye and Vision 25 Eye Irritation 25 Epidemiology of Eye Accidents Including “Arc Eye“ 25 Corneal and Conjunctival Inju
7、ries 25 Cataract and Other Lenticular Effects 26 Retinal Injuries and Vision Impairment 27 Nervous System 28 General Mortality 28 Loss of Consciousness 29 Manganese Intoxication 29 iiiLead Intoxication 30 Blood 30 Genitourinary System 31 Kidney Disease 31 Fertility and Potency 31 Cardiovascular Syst
8、em 31 Electrocardiograms 32 Blood Pressure 32 Gastrointestinal Tract 34 Acute Effects 34 Chronic Effects 34 Liver 35 Endocrine System 35 Musculoskeletal System 36 Chronic Fluorosis 37 Muscle Fatigue 37 Metal Fume Fever 37 Pathogenesis 37 Epidemiology 38 Ear and Hearing 39 Burns of the Ear 39 Acousti
9、c Trauma 39 Skin 39 Metal Burns 39 Ultraviolet Radiation Overexposure and Photoallergy 40 Skin Sensitization to Welding Fume Substances 40 Scleroderma 41 Injury, Accident and General Illness Statistics 41 Blood and Urine as Monitors of Welding Fume Exposure 41 Fate of Inhaled Welding Fumes 41 Blood
10、Studies 42 Urine Studies 43 3. Experimental Animal Studies 45 Inhalation of Welding Fumes and Gases 45 Intratracheal Administration of Welding Fume Suspensions 46 Distribution and Excretion of Inhaled Welding Fumes 47 Carcinogenicity 47 Metal Fume Fever 47 Effect of Welding Fumes on Influenza or Pul
11、monary Tuberculosis 48 Exposure to Arc Welding Radiation 48 4. Special Studies on Mutagenicity of Welding Fumes 55 Appendix A. Details of the Exposure 57 Formation of Fumes 57 Shielded Metal Arc Welding 58 Flux Cored Arc Welding 62 Gas Metal Arc Welding 64 Gas Tungsten Arc Welding 65 Plasma Arc Weld
12、ing 67 Submerged Arc Welding 67 Oxygas Welding 67 Extent of Fume Exposure 68 Gases Produced During Welding 71 Ozone 72 Nitrogen Oxides 74 Carbon Dioxide and Carbon Monoxide 74 Gases Formed from Decomposition of Chlorinated Hydrocarbons 75 ivRadiation from Arc Welding 76 Spectral Variation 76 Obstruc
13、tion of Radiation 77 Effect of Current 77 Reflection 77 Process Differences 77 Noise 77 Other Factors 78 Appendix B. OSHA Standard or Threshold Limit Value for Selected Airborne Contaminants and Physical Agents 79 Appendix C. Chronic Lung Disease Assessment 81 Pathogenesis of Lung Diseases 81 Lung F
14、unction Testing 81 Appendix D. Details of Experimental Animal Studies 83 Inhalation of Welding Fumes and Gases 83 Effects in Rats 83 Effects in Rabbits 89 Effects in Guinea Pigs 92 Effects in Mice 94 Effects in Cats 94 Intratracheal Administration of Welding Fume Suspensions 94 Distribution and Excr
15、etion of Inhaled Welding Fumes 97 Fluorides 97 Manganese 98 Silica 99 Mixed Fume Studies 99 Carcinogenicity Studies 101 Intraperitoneal and Subcutaneous Administration of Welding Fume Suspensions 102 Intraperitoneal Effects 102 Subcutaneous Effects 102 Metal Fume Fever 103 Effects of Welding Fume on
16、 Influenza or Pulmonary Tuberculosis 103 Influenza 103 Tuberculosis 104 Exposure to Arc Welding Radiation 105 Mice 105 Rabbits 105 Monkeys 106 Glossary of Medical Terminology 107 References IllPersonnel Authors of the report by Franklin Research Center were: Jon E. Villaume Khizar Wasti Deborah Liss
17、-Suter Shu-hsi Hsiao AWS Research Committee J.F. Hinrichs, Chairman F. Y. Speight, Secretary R.E. Kinser P. Ramsey P.C. Krueger A. Lesnewich N. Ward A.O. Smith Corporation American Welding Society Caterpillar Tractor Co. A.O. Smith Corporation Airco Welding Products Airco Welding Products Caterpilla
18、r Tractor Co. AWS Research Finance Committee E.B. Scripture, Chairman F. Y. Speight, Secretary W.B. Howell R.E. Bruggeman R.H. Schwegman EM. Hunt Teledyne McKay American Welding Society Consultant Caterpillar Tractor Co. General Electric Co. Allegheny Ludlum Industries VIIAcknowledgments The America
19、n Welding Society gratefully acknowledges the time and effort expended by the members of the Research Committee and the Research Finance Committee and the financial support of the program by industry contributions. Supporting Organizations Alloy Rods Division of Allegheny Ludlum Steel Company Westin
20、ghouse Electric Company Airco, Inc. Miller Electric Company The Heil Company United States Steel Corporation Union Carbide Corporation Babcock and Wilcox Company General Electric Company E.I. DuPont de Nemours this latter estimate includes pipe- fitters and mechanics who view welding only as one of
21、the tools of their trade. Therefore, the health and safety of this large occupational group is an important concern. Welders are not a homogeneous group. They work under a variety of conditions: outdoors, indoors in open as well as confined spaces, underwater, and above ground on construction sites.
22、 They also utilize a large number of welding and cutting processes. However, many of these have in common the production of fumes, gases, radia- tion, and other potentially harmful agents. The review that follows attempts to assess the effects of these agents on the health of welders. The discussion
23、 concentrates on health effects due di- rectly to the welding process. It does not attempt to treat safety problems, nor does it cover in any detail the accompanying hazards that, although often found in the welding environment, are not created directly by the welding process. Occupational health de
24、pends upon the conditions and exposures received in the workers environment. In Chap- ter 1 of this report, the physical and chemical agents to which welders may be exposed and the conditions of their generation are summarized; details are provided in Appendix A. In Chapter 2, the effects of this ex
25、posure on welders and others in the environment are reviewed. Since welders are exposed to a number of factors simul- taneously, the chapter is subdivided by organ system, not by agent. Effects on the respiratory system, skin, eyes, and internal organs are considered. Chapter 3 pre- sents the result
26、s of studies in experimental animals; the review concludes with a discussion of special studies of the mutagenicity of welding fumes. XlllExecutive Summary Most commonly used welding processes emit fumes, gases, electromagnetic radiation, and noise as byproducts of their operation. During welding, w
27、orkers are poten- tially exposed to all of these agents. The fumes are chem- ically very complex, arising primarily from the filler met- als and any electrode coatings or cores. The potential exposure varies with the process and welding conditions employed. Numerous reports of the effects of welding
28、 on health have been published. Many cases of acute poisoning, due to excess exposure to one or more gases and fumes, have been documented. However, other than lung involvement, few chronic effects have been attributed to welding, and, in almost all the studies of chronic effects, welding of fer- ro
29、us metals was involved. This does not necessarily mean that welding ferrous or any other metals presents no routine health risks. Frequently, published studies have not been appropriately designed to detect the effects of chronic exposure and have not adequately examined special groups (for example,
30、 welders of aluminum or stainless steel) with unique exposure factors. Conclusions resulting from this review are presented briefly in the following sections. Acute Poisoning Exposure to ozone generated during gas shielded arc welding, especially of aluminum, may produce irritation and inflammation
31、of the respiratory tract, excess fluid and hemorrhage in the lungs, and sometimes headache, lethargy, and eye irritation. Severe cases could be fatal. Ozone is generated at a distance from the arc by the ac- tion of the emitted ultraviolet radiation (240 nm) on atmospheric oxygen. Nitrogen oxides, w
32、hich are pro- duced in welding arcs and flames by thermal oxidation of atmospheric nitrogen, produce similar respiratory tract effects. Metal fume fever occurs in welders who inhale zinc- containing fumes, although other fume components may also produce the symptoms of this condition; for exam- ple,
33、 a metallic taste, chills, thirst, fever, muscle aches, chest soreness, fatigue, gastrointestinal pain, headache, nausea, and vomiting. The symptoms usually subside within 1 to 3 days of exposure without residual effect. Chronic Lung Conditions Protracted inhalation of welding fume particles leads t
34、o their accumulation in the lungs, a condition seen as dense areas on chest x-ray films. The severity of changes in lung x-rays is proportional to the length of welding experience; however, the changes seen in such x-rays are not necessarily associated with reduced lung function or disease. In gener
35、al, welders of ferrous materials have been found to have an increased frequency of respiratory symptoms such as chronic bronchitis. No conclusive studies have been made to determine whether reduced lung function, emphysema, or other chronic respiratory conditions generally occur more frequently in t
36、hese groups than in nonwelders. Significant levels of ozone are produced in certain gas shielded welding operations. Lengthy exposure of experimental animals to this gas has induced the forma- tion of fibrous tissue and caused emphysema-like and other effects in the lungs. No studies of the long-ter
37、m effects of this gas on welding populations exposed to it have been undertaken. Studies of the effects of welding fumes on experi- mental animals have indicated excess deposition of fi- brous tissue in the lungs when a variety of metals were welded. However, in these experiments, fume concen- trati
38、ons were always very high, and experimental condi- tions were incompletely described; therefore, it is dif- xvficult to relate the importance of these findings to the welding experience. Eye Ultraviolet (170 nm), visible, and infrared radiation are emitted by the welding arc. Welders not wearing eye
39、 protection and others in the vicinity of the arc are at risk to the effects of this radiation. Ultraviolet radiation produces the condition known as “arc eye,“ an acute inflammation of the external structures of the eye; the symptoms disappear within 1 to 2 days. Infrared radiation penetrates the i
40、nterior of the eye and can cause burns on the retina. There is no evidence that cataracts occur more fre- quently in arc welders than in nonwelders; the results of studies designed to detect cataracts in welders have yet to be published. Skin Exposed skin is susceptible to the effects of ultra- viol
41、et radiation from the arc (for example, erythema) and of any fume components capable of skin sensitiza- tion or irritation. Chromium compounds, which occur in stainless steel welding fumes, are a frequent cause of dermatitis. Cardiovascular Disease Electrocardiograms and blood pressures have been me
42、asured in several studies. In most of these, electro- cardiograms of welders did not differ significantly from control groups of nonwelders, and welders have been shown to have normal or slightly lower blood pressure than the control groups. Carbon monoxide is generated from carbon dioxide in the ga
43、s shielded welding processes. It combines avidly with hemoglobin, reducing the oxygen-carrying capacity of the blood. Exposure to carbon monoxide may present an added health risk to those with heart disease. No studies of heart disease in welders performing carbon dioxide shielded welding have been
44、documented. Nervous System and Other Organs Lead and manganese can occur in the fumes of certain welding operations; both are toxic to the nervous system. Except for those attributable to these two substances, no reliable reports of effects of welding exposure to the nervous system have been publish
45、ed. There is no significant evidence that welders have a higher incidence of other chronic diseases. Carcinogenicity Based upon available information, there does not ap- pear to be any evidence that exposure to welding fumes and gases induces lung or other forms of cancer. Further study is required of groups exposed to specific kinds of fumes. The welding arc emits ultraviolet radiation of wavelengths that produce skin tumors in animals, but no study of this effect in welders has been reported. xvi
