I '1 NTIS Iloo.at HEALTH EFFECTS OF EXPOSURE TO WOOD DUST / I A SUMMARY OF THE LITERATURE NIOSH LIBRARY SYSTEM MORGANTOWN LIBRARY 10S·; h:LLOWDALE ROAD MORGANTOWN, WV 26505 U.S. Department of Health and Human Services Public Health Service Centers for Disease Control National Institute for Occupational Safety and Health Division of Standards Oevelopment and Technology Transfer June 1987 DISCLAIMER Mention of the name of any company or product does not constitute endorsement by the National Institute for Occupational Safety and Health. i i FOREWORD This document identifies and summarizes the literature that describes the potential health effects resulting from exposure to wood dust. It was developed by the National Institute for Occupational Safety and Health (NIOSH) at the request of the U.S . Department of Labor, Occupational Safety and Heal th Administrat ion (OSHA). This document provides a comprehensive synopsis of the literature related to wood dust. The conclusions described herein are those of the cited authors. The report itself does not contain NIOSH recommendations for regulating occupational exposure to wood dust, nor is it a itical evaluation 0 the literature . Such recommendations and evaluati n ere preclud y e volume of publ ished data and the relat i vely sh r dl ine 0 devel pment of the document. ",Id " II" ..... o . istant Surgeon General a, ector , National Institute for \ ccupational Safety and Health Centers for Disease Control iii , ABSTRACT This report identifies and summarizes the literature on the potential health effects of exposure to wood dust. This comprehensive literature review def i nes wood. discusses occupat i ona I exposure standards and reconmendat ions for wood dust. describes reports of animal and in vitro testing. and examines human health effects including dermatitis. allergic respiratory effects. IllUcosal and nonallergic respi ratory effects. and carcinogenici ty. Also included is a campi lation of wood dust concentration ranges reported for var i ous woodwork i ng ope rat ions and a br i ef discuss i on of wood dust control technology. The report does not contain NIOSH recommendations for regulating occupational exposure to wood dust. iv • CONTENTS Foreword .... iii Abst ract . iv Tables ..... vi Acknowledgments vi i I. In t roduc t ion . 1 II. Animal and In Vitro Studies 9 " I. Dermat i tis . ...... 17 IV. Allergic Respi ratory Effects ... 27 V. Mucosal and Nonallerg ic Respiratory Effects 41 VI. Carcinogenici ty ............. 49 VI I. Industrial Hygiene Measurements and Controls 89 Re fe rences . 129 v TABLES Number Page 1 Wood dust exposure standards and recommendations . 3 2 Woods causing dermatitis 18 3 Selected case reports of wood dermatitis 22 4 Selected case reports of allergic respiratory effects caused by wood dus t . 28 5 Comparison of Type I and Type II I allergic responses 34 6 Wood dust concentrations measured in the workplace in various studies ............... 91 7 Summary of total dust concentrations in sanding operations 120 8 Summary of total dust concentrations in sawing operations 121 9 Summary of total dust concentrations in woodworking operations (excluding sanding/sawing) .. 122 10 Summary of general area samples for total dust collected in woodworking operations ... .. ..... 124 11 Summary of respirable dust concentrations in woodworking operat ions . 125 12 Summary of particle size data in woodworking operations 126 13 Recommended exhaust volumes for woodworking machinery 128 vi , ACKNOWLEDGMENTS This document was developed by the Division of Standards Development and Technology Transfer, National Institute for Occupational Safety and Health. Rodger L. Tatken was responsible for preparing the document. Contributions of the following Division staff are gratefully acknowledged: Howard R. Ludwig, for compilation of the industrial hygiene sampling data in Section VII; and Bryan D. Hardin, Ph.D., G. Kent Hatfield, Ph.D., Theodore J. Meinhardt, Ph.D., Richard W. Niemeier, Ph.D., John J. Whalen, lawrence F. Mazzuckell i, David H. Groth, M.D., and Sheldon H. Rabinovitz, Ph.D. (currently with the U.S. Environmental Protection Agency), for their critical reviews and cOllll1ents. NIOSH review of this document was provided by Stephen G. Bayer, Raymond E. Biagini, Ph.D., JeAnne R. Burg, Ph.D., John F. Gamble, Ph.D . , Charles McCammon, Ph.D . , Michael A. McCawley , Ph .D., and William J. Moorman. Carolyn A. Browning performed editorial review. vi i • I . I NTROOUCTI ON Th i s document i dent if i es and summar i zes the literature that descr i bes the potential health effects resulting from exposure to wood dust . For purposes of this document, wood dust is defined in its broadest sense--that is , any wood particles arising from the processing or hand I ing of wood. Because this definition is so broad, every effort has been made to describe as thoroughly as possible the ci rcumstances of the wood dust exposures (e.g., type of wood, dust concentration, and concomitant exposures) as reported by the authors . It shou Id be noted, however. that for much. of the literature. this type of information is not avai lable. The document contains seven sections. This introductory section briefly defines wood and discusses occupational exposure standards and recommendations for wood dust. Section II summarizes reports of animal and in vitro testing . Sections III - VI examine human health data and are arranged by effects. including : dermatitis, allergic respiratory effects, mucosal and nonallergic respiratory effects, and carcinogenicity . Section V.l1 contains a compi lation of wood dust concentration ranges reported for various woodworking operations and a brief discussion of wood dust control technology. Wood is a complex biological and chemical material that consists primari Iy of cellulose, hemicellulose, and I ignin. Cellulose is a I inear glucose chain that serves as wood's skeleton. Hemicellulose is a small po Iysacchar i de that may ass i st in ce II growth and matu ra t ion. ' L i gn i n is a high molecular weight polymer of phenoxy I-propane units that functions in holding wood cells together. Wood may contain a variety of complex organic compounds. including glycosides, quinones. tannins, stilbenes. terpenes, aldehydes, and coumarins. It is beyond the scope of this paper to provide a detai led discussion of the chemistry of wood. The reader is referred to any of numerous texts on the subject (e.g .• Esau 1965,1977; Browning 1975; Kollmann and Cote 1968; Sjostrom 1981; Haygreen and Bowyer 1982); reviews are provided in Woods and Calnan (1976), IARC (1981), and HoII iday et al. (1986) . Woods have been divided into two different classes. hardwoods and softwoods. each with its own cellular structure and chemical composition. For example, hardwoods have a lower lignin content than softwoods (Holliday et al. 1986). Hardwoods (angiosperms) are the deciduous broad-leaved flowering spec i es. Softwoods (gymnosperms) are the con i ferous spec i es that do not normally shed their leaves in winter. According to Woods and Calnan (1976), the first occupational reference to adverse hea I th effects f rom wood was made in 1700 by Bernard i no Ramazz i n i , 1 • who reported nose and eye irritation in pitsawyers and headaches in wood turners. In 1902, upper respiratory tract i nflanwnation was described in men working with sequoia wood, and throat and eye irritation was reported in workers who used a boxwood substitute (Woods and Calnan 1976). Three years later, Legge (1905) reported that "African boxwood" caused such severe symptoms among Lancashi re shutt lemakers that the men refused to work wi th it. Following these initial case reports, a substantial body of literature on the health effects of exposure to wood and wood dust has accumulated. Two comprehensive reviews of wood toxicity include Woods and Calnan (1976) and Hausen (1981); briefer treatments are provided in Hanslian and Kadlec (1966), Kadlec and Hans I ian (1983), and Jagels (1985) . Until recently, occupational exposure to wood dust was regulated in the U.S. under OSHA's inert or nuisance mineral dust standard (29 CFR- 1910.1000 Table Z-3) at an 8-hr time-weighted average (TWA) concentration of 5 mg/m3 air for reapirable dust and 15 mg/m3 for total duat. However, several OSHA citations for exceeding nuisance dust levels for grain duat exposures were appealed to the Occupational Safety and Health Review Commission (OSHRC). These cases, Bunge Corporation (OSHRC Docket Nos . 77-1622, 78-838, and 78-2213) and Krause Mi II ing Company (OSHRC Docket No. 78-2307), challenged the appl icabi Ii ty of the nuisance dust standard to soybean dust and corn dust, respectively. In both cases, the Review Commission held that the nuisance dust standard did not apply to organic dusts. In a third case that involved wood dust exposure (Bemis Manufacturing Company, OSHRC Docket No. 80-3443), the Administrative Law Judge ruled that wood dust was not an inert mineral dust and therefore not subject to the nuisance dust standard. Although this rul ing was not precedent setting, OSHA elected not to appeal it to the OSHRC. No other related cases have since been brought before the Review ConInission, and OSHA has not amended Table Z-3 (29 CFR 1910.1000) . Therefore, the current law, as stated by the Review Commission'S decisions, is that the nuisance dust standard applies to mineral dusts only and not to organic dusts . Several other countries currently regulate occupational exposure to wood dus t . Some coun t r i es name spec i f i c wood spec i es (e. g., "p i ne, oak, fir, and beech" in the German Democratic Republ ic) or a particular class of wood dust (e.g., "hardwood" and "softwood" in Canada and Norway; "nonallergenic" in the Un i ted Kingdom and the Nether lands) .