Document NG5vEEV7p7xQ73zxvZLXK86Jp

VOLUME 32, NUM8EK I January. 1^71 MM| American Industrial Hygiene Association Journal 111 m American Industrial Hygiene Conference Royal York Hotel, Toronto, Canada May 24-28, 1971 PLAINTIFF'S EXHIBIT WV-M3WI PLAINTIFF'S EXHIBIT mum  .V Exposure of Insulation Workers to Airborne Fibrous Glass DOUGLAS P. FOWLER, J. LeROY BALZER and W. CLARK COOPER, M.D. School of Public Health, University of California, Berkeley, California 94720 (g A study was undertaken to define the airborne concentrations of fibrous glass exposures of workers using prefabricated and other fibrous glass insulation ma terials. More than 100 fibrous glass products were examined and samples of airborne fibers were collected from various operations with such materials. Airborne concen trations ranged from 0.5 to 8 fibers/ml with mean fiber diameters from 2.2 to 8.4 micrometers. The mean diameter of fibers from the parent product were found not to be a reliable predictor of the mean diameter of the airborne fibers resulting from work with the products. The concentrations of airborne fibrous glass found in this study are not likely to be of tong-term biological significance. Introduction those workers, and in areas surroundir. 'T' HIS STUDY WAS UNDERTAKEN as operations. part of our investigation of the work The general work environment of inst environment of insulating workers; and is a workers has been described previously, continuation of a previously reported study ticularly in relation to asbestos exposur^ on the exposures of insulation workers to asbestos fibers and other environmental stresses.1-1 have been many of the chemical and phj properties of fibrous glass.3 The use of fi glass insulation has increased markedly . The stated objective of this part of our study was: "To define qualitatively and quan titatively the airborne concentration of fibrous cent years, and it is now probably the] commonly used thermal and acoustic. sulation material. As its uses have inert glass in the breathing zones of workers en so have the variety of forms in whic_. gaged in the fabrication, application, finish ing, and other operations involved in the installation of prefabricated and other fibrous glass insulation materials." To attain this objective: (a) over 100 samples of fibrous glass insulation products were examined: (bl the conditions of use of these materials were evaluated during visits to over 50 construc tion sites where the materials were being in produced. It has found widest use in the of "batts" or"blankets" of light-density glass either with or without a backi> protective and/or water impermeable} terial such as foil, vinyl, or treated papei this form it is used by the insulation wtu studied to thermally insulate ventilation g work. Another important source of exp to the insulation worker is the handlir stalled by members of the International Asso higher density "boards" of fibrous . ciation of Heat and Frost Insulators and (which may be coated with Neoprene orv Asbestos Workers Local 16 (Northern Cal ifornia and Northern Nevada!; and (c) the substances) used for the thermal or acou^, insulation of walls, ceilings and otherj actual concentrations of airborne fibrous glass surfaces, particularly in mechanical . were determined during representative instal lation operations by taking and analyzing and ventilation plenums of large buildii third primary source of glass fiber exf samples of the air in the breathing zones of is in the installation of fibrous glass 86 in, in an Industrial Hy<. in which hah ,..iii,n'k'<d fibrous glass a ;llMii.in"ii. Fibrous glass bv insulation work tl:* j *ii.ii insulation of mci .,u- formed into sped. %::< v y*~.- - Iteminc* of the-varying , on!i.u tin's, it is diffici h-'m.iI" exposure to fibt ;,,..ii.iiile that more than niMil.itor's work experent (Tilifornia and Nevada loc uiih fibrous glass insulatit U,,nrr. usage varies ai rX|.. ia-nce may be almost Kutiitei. the use of thesi tinning to increase. 1 11.- job classifications t the description of work wi ing iiioducts do not app uoth with fibrous glass ] nun will ordinarily fab finidi a single piece of fib Therefore, such classificat except where definite s< t.i'U was observed. Fibrous Glass Insulation M. I';,' i\-seven fibrous glass wen* supplied by manufai in tin- project. Additional in ts were collected in the t wen- duplicates of those su product, a representative including portions of all material, and this sample u nli.i'e contrast microscopy iiuiiinting medium with i*e.<u\ that of glass. The dividual fibers were estim; with a Porton eyepiece r di'tnhution of fibers in e. mined. Although it is cuteri/e particle size distribi. in- in and geometric stanc. a.I- inn done lor these da bution of fiber diarneters the expected simple log-n Although some of this ( normality was undoubted; orkers to ass :lark cooper, m.d. ley, California 94720 llrations of fibrous glass rous glass insulation maand samples of airborne erials. Airborne concenameters from 2.2 to 8.4 product were found not me fibers resulting from rous glass found in this ork environment of insti n described previously! ion to asbestos exposure of the chemical and phj ms glass.3 The use of fifl as increased markedly a t is now probablv thej thermal and acoustic^ As its uses have incrj 'ty of forms in whief ound widest use in the kets" of light-density or without a backus water impermeable] vinvi. or treated paper! 1 by the insulation wo| y insulate ventilation < oortant source of exp vorker is the handlid wards" of fibrous ed with Neoprene or r the thermal or acot , ceilings and other! ly in mechanical urns of large buildL e of glass fiber exp n of fibrous glass Industrial Hygiene Association journal Jnl'ii"1" 87 in which half-round sections of HI))!,' ...ril fibrous Fibrous glgalsasssarepruosdeudctfsor thermal are also " I* insulation workers for acoustical/ insulation of mechanical equipment, ul formed into special shapes on the job variation, which was then magnified in effect by our relatively small samples, much of the deviation is "real," and -was confirmed for several products by sizing 400 to 500 fibers. There was "smoothing" of the size distribu tion curves, and extension of the ^rafige" sizes encountered in larger samples; but the |!c( .nisc of the varying emphases of local ,nn<iors. it is difficult to estimate a -(\jii<.fi exposure to fibrous glass, but it is ofi ifile that more than half of an average basic conclusions were not changed. To permit comparison among materials, ac cumulated data on product fiber diameters are summarized in Table I. ___ Insulator's work experience (in the Northern California and Nevada local union studied) is Exposures of Insulation Workers ,,idi fibrous glass insulation of various types. The exposures of insulation workers to However, usage varies and some insulators' fibrous glass, like their exposures to other experience may be almost totally with glass, environmental contaminants, cannot be de further, the use of these materials is con- scribed by time-weighted average exposures ,inning to increase. because of the nature of the trade. An in The job classifications used by Balzer1 for sulation worker will be exposed, during a ijie description of work with asbestos-contain- working day, to a series of "peak exposures" iiiir products do not appropriately describe to the material which he is handling. One work with fibrous glass products, since one man will ordinarily cut, apply, and finish a man will ordinarily fabricate, apply, and single piece of glass fiber insulation material. finish a single piece of fibrous glass material. This differs from tire situation usually found Therefore, such classifications are not used, in a production plant, or in some applications except where definite separation of work of asbestos-containing products, where a ijxks was observed. worker may repeat a single operation for most Fibrous Glass Insulation Materials of his working day, so that environmental con tamination tends to fluctuate less widely. The fifty-seven fibrous glass insulation products insulation worker moves about frequently, werr supplied by manufacturers cooperating and may work on several floors of a large . in the project. Additional samples of 50 prod building in a single working shift, with a con ucts were collected in the field, some of which sequent variety of exposure to environmental were duplicates of those supplied. From each contaminants. Further, the worker who today product, a representative sample was taken, is installing calcium silicate insulation in an including portions of all apparent types of enclosed boiler room, with extremely high material, and this sample was examined under concentrations of airborne asbestos fibers, may phase eontrast microscopy-at 430X using a .luuinting medium with a refractive index Table I iieiou diet of glass. The diameters of 50 in dividual fibers were estimated by comparison Diameters of Fibers of Various Fibrous Glass Products with a Porton eyepiece reticle, and the size distribution of fibers in each product deter mined. Although it is customary to charac- Material Xo. of SatnpU-s Range of arithmetic Means 1) Mean of Means tim i eii/e particle size distributions bv geometric mean and geometric standard deviation, this "as not done for these data, since the distri bution of fiber diameters did not exactly fit the expected simple log-normal distribution. Although some of this deviation from lognormality was undoubtedly due to sampling Duet liner Duct wrap Industrial Wall insulation Pipe insulation Prefabricated duct Basic fiber Acoustical tile Miscellaneous Packing wool Building insulation 21 4.4-1 / d i 6.7 11 4.1- 9.4 5.4 1H 4.4-10.: 8.1 n8 u 5 h 4 14 4.4- 9.0 5.7-11.3 54..0(M-11l..54 4:..o0-- 97..C0 4.9-11.5 87..00 8.8 9.1 5.5 8.0 8.2 88 February, . Table II Concentrations and Dimensions of Airborne Fibers from Various Operations Using Fibrous Glass Insulation Operation Duct Wrapping Insulation Pipe Insulation Fan Housing Insulation Site tt i 3 3-1V 8 4 Parent Material mean fiber diameter ( fim) fibers/tnl 5.5 1.26 6.5 0.90 6.4 4.0 0.31 0.79 4.1 1.40 t.33 7.5 0.80 5.8 1.20 5.5 2.34 7.2 0.33 5-1 7-1 7-II 5-111 6 10.2 8.1 76 7.8 8.1 8.5 6.7 6.0 6.0 5.6 3a26 4.18 8.08 0.93 0.48 0.57 5 II 6.9 1.57 Air Samples: Breathing Zone mean fiber diameter (fim) Le nglh 7l" >78*tm 4.7 24 4.0 40 76 60 3.4 46 54 3.6 36 64 2.6 62 38 2.3 60 40 2.5 83 17 6.2 37 5.0 42 63 58 7.4 30 7it 8.4 47 3.5 59 53 41 3.8 60 40 3.1 71 29 4.1 40 60 3.4 50 50 3.5 88 12 f\l>ers/ml 0.09 Air Samples: Area 'jflBj mean fiber diameter <Mm ) Length <78*im 4.0 43 - * 400.02 5.5 0.03 3.7 0.07 0.03 <0.01 0.09 0.08 0.47 0.34 3.7 4.5 _ 6.2 7.9 2.8 O0 54 4" ,,4 50 49 If 55 C ; 60 86 jP* 0.05 2.3 0.05 2.6 88 0.03 2.6 86 XM 0.02 3.1 66 Sg 0.09 3.5 66 0.09 2.9 65 0.20 3.4 82 ifl *78 /tm is the equivalent length of the major division of the Pcrton reticle with our optical system. tomorrow be wrapping ducts with fibrous glass in a relatively open area of the same building, with natural ventilation from open windows serving to remove airborne glass fibers from his vicinity nearly as soon as they are pro duced. Exposures, then, cannot be accurately characterized as though they were constant, but must be related to the work being per formed at the time of the exposure. Short term sampling periods are required in order to assess the environmental exposure. Concentrations of Glass Fibers in Air In Table II are shown the mean fiber di ameters of the fibrous glass materials used, and concentrations and sizes of the airborne glass fibers lotind during installation of fibrous glass insulation at the construction sites front which air samples were taken. Sampling techniques used in this study have been described previously.2 Briefly, air for breathing zone samples was drawn through 0.8 /cm (mean pore size) Milli membrane filters by MSA Monitaire ptj at flow rates of 2 to 3 liters per minute.; samples were taken in the same way, 4 pumps with flow rates of 25 to 30 liter minute. The filter holders for the samples were about 5 to 6 leet above level and 10 to 20 feet away lrom the tions of the installation operations. Samp periods were 20 to 60 minutes. It will be noted that none of these re are expressed ``gra\ imetrically'' (e g. glass/nr air). The air at construction, sites is notoriously dusty, and any attemp relate a total gravimetric sample to the centration ol fibrous glass is impractical i misleading. Secondly, the tentative Thi? old Limit Value (American Conferenc Governmental Industrial Hygienists) c mg/m: lor fibrous glass only applies to with diameters less than "5 to 7 micromet? Our experimental work has shown that jfll, lit an Industr; .a GLASS fiBE = tiuiRE 1. Accunn ji-i diameters Iron n<> size-selectiv e > jll fillers less than (his range and rejec vtT^.I ' - Thus, the he requirements ot a:i borne fibers, sizi Meiehts of individu .crime, with many uc estimate that a nil with a mean aii micrometers and a l of 50 micrometers viniotric concentrate total fibrous glass. T concentration of fib applicable (less th: anieter'i is apprQ.xii a liber concentratio his of course vari< mbutions. Discussion The exposures < v.->rous glass during dav< insulation pro- fibers/ml with a `>1 1.8 fibers/ml. 1 than their exposui tcrials.2 The potent struction trades to result of "fallout'' 1 "etc still lower, r tiller /nil to 0.47 fil February, /<j {m`ian Industrial Hygiene Association Journal 89 arious Operations i/ml 9 Air Samples: Area mean fiber diameter 4.0 Length <J <78pm 43 >7#j S71 >2 5.5 40 6oJ 13 . 3.7 78 - 3.7 62 3&1 3 4.5 54 l_ _ 9 6.2 50 8 7.9 49 5tjj 7 2.8 55 t q o 60 40S j 2.3 86 Ml i 2.6 88 12M t 2.6 86 lt-S t 3.1 66 ) 3.5 66 2.9 65 3.4 82 tsl optical system. ;nean pore size) Millip >y MSA Monitaire pi o 3 liters per minute, a in the same way, us ates of 25 to 30 liters r holders for the it 5 to 6 feet above flo feet away from the lc tion operations. Samplij 60 minutes. that none of these rest -avimetrically" (e.g. e air at construction Justv, and any attempt^ nctrir sample to the coil is glass is impractical ar ly, the tentative Thres American Conference rstrial Hygienists) of 1 ;lass only applies to fib han "5 to 7 micrometer^ oik has shown that theft ..3? GLASS FIBER DIAMETER, Figure 1- Accumulated percentage distribution ; ^|M., diameters from all sampling sites. Ficure 2. Cumulative distribution of fiber di ameters from all samples. j< n<' size-selective sampler which will collect ;,ll libers less than any specific diameter in this range and reject all larger fibers (or viceversa:. Thus, the only way to comply with die requirements of the TLV is to collect all airborne fibers, size them, and estimate the weiirhts of individual fibers. Using this pro cedure. with many simplifying assumptions, we estimate that a concentration of 1 fiber/ ml with a mean airborne fiber diameter of 4 micrometers and a mean airborne fiber length of 50 micrometers is equivalent to a gra vimetric concentration of 1 to 1.5 mg/m3 of total fibrous glass. The estimated gravimetric concentration of fibers to which the TLV is applicable (less than 7 micrometers in di ameter) is approximately 0.5-0.7 mg/m3 for a fiber concentration of 1 fiber/ml, although this of course varies with the fiber size dis tributions. Discussion The exposures of insulators to airborne fibrous glass during the application of fibrous ?lass insulation products ranged from 0.5 to H fibers/ml with a median of 1.26 and mean m 18 fibers/ml. This is significantly lower than their exposures to other fibrous ma terials." The potential exposures of other con struction trades to airborne glass fibers as a result of ``fallout" from insulating operations "ere still lower, ranging from below 0.02 hber/mi to 0.4 7 fiber/ml with a median of 0.07 fiber/ml and a mean of 0.1 fiber/ml, at a distance of 10 to 20 feet from the insulator during his application of fibrous glass ma terials. The maximum levels were found in con fined spaces, where there was little circulation of air, and where clean-up (including sweep ing and packing of scraps of fibrous glass residue) had generated high concentrations of airborne dust of all kinds. Although, as stated previously, it is difficult to generalize about the occupational environment of the insulator, it is probable that exposures of this sort are relatively rare. It is most common for clean up to take place only at the end of a work shift. Because of the bulkiness of fibrous glass' insulation products, cutting is usually done in a relatively open area which affords the space necessary for layout and measurement. One of the striking findings of the study,' as shown in Figure 1, is that the mean fiber diameter of the parent products is not a re liable predictor of the mean diameter of the fibers in the aerosol generated from these products. Although the determinants of "respirability" of airborne fibers are not fullv agreed upon, it is probable that respirability is diameter-dependent.4 TimbrelFs experi ments, using the aerosol spectrometer, sug gested that fibers with densities of less than 3.5 g/cm3 and large aspect ratios (length to width ratios) could be considered "respirable" if the fiber diameter was less than 3.5 micro- 90 February, meters. Fibrous glass (with a density of 2.42.6 g/cmJ fits his definition and thus glass fibers less than 3.5 microns in diameter will be defined as "respirable." As can be seen in Figure 2, about one half of the airborne glass fibers generated from the handling of fibrous glass insulation materials are below this upper limit. Thus, it would seem that the often en countered statement that the diameter of the majority of glass fibers is such that they will not penetrate to the lower respiratory tract is true of the parent materials, but generally not of the airborne fibers which are of primary concern in occupational health. Although our observations might appear to be at variance with those of Johnson et al./` who recently studied the airborne dust concen trations in glass fiber insulation and textile manufacturing plants, our conclusions are es sentially the same as theirs; the concentrations of small diameter airborne fibers are very low. What do the concentrations of fibrous glass which were found mean in terms of potential hazard to health? The consensus of present opinion is that fibrous glass, although mechanically irritating to the skin and upper respiratory tract, is per se relatively inert and that it does not cause chronic pulmonary dis ease when inhaled.*'5 Although Milby and Wolf have reported cases indicative of res piratory irritation in individuals who had re moved insulation materials or otherwise been exposed to fibrous glass,10 and Murphy in 1961 reported a case of hemorrhagic bron chiolitis after heavy exposure to dust during removal of glass insulation,11 no documented cases of pneumoconiosis or other chronic pul monary diseases due to fibrous glass are known to us. Intubation studies in lower animals have shown relatively little biologic activity.1-15 T his is the basis upon which the American Conference of Governmental Industrial Hy gienists, in 1969. set the tentative threshold limit value for fibrous glass at the same level as that for inert dusts, now 10 mg/m3 (for fibers under 5 to 7 micrometers in diameter). Although gravimetric determinations of glass are not feasible in the construction trade, the fiber counts that we observed have been cal- culated to represent amounts of glass far? low the TLV. These were the concentratl during actual installation operations and time-weighted averages. The insulator's i weighted average would be much lower the figures given. Because there are unquestionably respit fibers in most fibrous glass materials and are many possible variations in coat binders, etc., prudence dictates that ther continued surveillance of the exposure various groups to fibrous glass as is being j by the Public Health Service.5 The as absence of chronic effects should be che by appropriate long-term observation of : whose work involves frequent or daily] halation of glass. Conclusions 1. Insulation workers, during the ac application of fibrous glass insulation pro were exposed to airborne concentration glass fibers ranging from 0.5 to 8 fibers! with a median of 1.3 fibers/ml and me 1.8 fibers/m 1. 7 2. The computed gravimetric conce tions of airborne glass fibers less than 7J in diameter did not exceed the tent3 Threshold Limit Value of 10 mg/m3 duq any peak period. The majority of these ig surements were less than 1.0 mg/m3. | 3. No time-weighted average could computed which would be representativ a work day exposure. In any case, it wj be considerably less than the peak cor trations measured. ^ 4. Insulators work with fibrous glass: taining materials from less than 10% to lfl of their time depending on employer and 9 of construction site. 9 5. It is doubtful that the concentration airborne fibrous glass found in our study] of long-term biological significance. M Acknowledgments ^ The technical assistance of Mr. Murchio and microscopy of Mr. Arturot Leon are gratefully acknowledged. This search was supported in part by the Nat Insulation Manufacturers Association. References 1. BaL/lr, J. L.: Industrial Hygiene for Insulation tts. J. Occvp. Med. lU: 1 (Jan. 1%8). 'S' ' j.iiiiiiti't Indush J. L., and ' >4 (nsuUtinq V .V ss: (1968). f\M CM. tPd..: 9F:iUi 4 Iivbwml, V.: The J KHects ol AAbes V', JLfcSr.Sl, 1965). L., w of Fibr<< / io M5 (1969). A. X. M.: Pul Fibers. J. Otcu}< k-'n'is, J. L.: Hcaii! ijt.l Annual Inc., 5231 < 15232 ( 197(1 . * l ih'H'-N, H. M. D.: Fibrous Class Worftt ,/r. Sov. 22, 1968 (M The Bureai is presenting 29-Apnl 2, If staff, and rela t ides an oppo methods at th< and organ:zat equipment ant logical, pathol reviewed. Ani tures, and was: opportunity to to man, einergt Inquiries ma Safety and Hea made by teieph- A five-day .co <ored by the U n ment in BerkeK towards the prat ment of the Fee; cepts of noise an pairment. the efi servation prosrra. control measures receive the 1967 Service and the vtiene Association Advanced ehr< panies. The enrt unuing Exiucatioi forma", 2223 Full: ,February "present amounts of glass far] /. These were the concentrat il installation operations and d averages. The insulator's rage would be much lower ven. ere are unquestionably respi fibrous glass materials and ossible variations in coat., prudence dictates that therdi; veillance of the exposures! ; to fibrous glass as is being Health Service.5 The assu -onic effects should be che< long-term observation of t tvolves frequent or daily ss. t workers, during the act brous glass insulation prodtL 0 airborne concentrations! png from 0.5 to 8 fibers/ tf 1.3 fibers/ml and me >uted, gravimetric concen%t ; glass fibers less than 7 1 not exceed the tentat Value of 10 mg/ma dt The majority of these mej ?ss than 1.0 mg/m3. eighted average could would be representative! ;ure. In any case, it wo ess than the peak cone ork with fibrous glass ora less than 10% to 1( iding on employer and that the concentrationsj tss found in our study peal significance. assistance of Mr. Jac scopy of Mr. Arturo acknowledged. This d in part by the Nation turers Association. ;al,H:'nt tor Insulation \vc' - 1 (Jar,. IS>>8). j Industrial Hygiene Association Journal 91 K | L-. and W. C. Cooper The Work Environ* ,,1 ln>tlaring Workers. Amer Ini. Hri- assoc. ]. C. F-' Fiber Glass--Chemistry and Technology. 339 (July 1967). tic, V.: The Inhalation of Fibrous Dusts, Biolog{ of Asbestos. N. Y. Academy Science 132: l^,HrNM-ih>Nc-. :Dn-. L1%., 5)e.t el.: Exposure to Fibers in the vfimilawturc of Fibrous Glass, Amer. Ind. Hyg. Assoc. lit; 543 (1969). >.n-sk N. M,: Pulmonary Hazards from Exposure to Fibers. J. Occup. Med. 9: 345 (July 1967). J- F.: Health of Fibrous Glass Workers. Trans. ./,,/ Annual Meding, Industrial Hvciene Foundation of In--c., 523] rCentre Avenue, Pittsb> u-rg-uh, Pt>e__n_n- 15232 (J970). ( limn.', 11- D.: 1HF Statistical Studies of Health ,,f f ibrous Glass Workers. Proceedings Fibrous Dust Sem- n,,f. 22, 1968 (Medical Series: Bulletin No. 16-70) Industrial Hygiene Foundation of America, Inc.. 5231 Centre Avenue, Pittsburgh, Pennsylvania 15232 (1970). Gross, P.: A Comparison of the Effects in Experimental Animals of Certain Fibrous Dusts. Proceedings Fibrous Dust Seminar, Nov. 22, 1968 -(-Medical Series: Bulletin No. 16-70) Industrial Hygiene Foundation of America. Inc., 5231 Centre Avenue, Pittsburgh. Pennsylvania 10. 1M52il3b2y,(1T9.70H).., and R. C. Wolt: Respiratory Tract Ir ritation Irom Fibrous Glass Inhalation. /. Qcc*p~.M-cd:d& 11: 409 (Aug. 1969). J %jt. Z U. Muhphy. G. B.; Fiber Glass Pneumoconiosis. AKfA Arch. Envtrn. Health 3: 704 (Dec. 1961). 12. ScHEPKts, G. W. H.: The Biological Action of Glass Wool. AMA Arch. Envirn. Health 12: 280 (Sept. 1955). Gross, P. et al.: The Pulmonary Response to Fibrous 13- Dusts of Diverse Composition. Amer. Ind. Hyg. Assoc. J. 31: 125 (1970). - Received June 8, 19^0 Safety in the Laboratory The Bureau of Occupational Safety and Health, U. S. Public Health Service, is presenting a course "Safety in the Laboratory'' in Cincinnati, Ohio, March 29-April 2, 1971. This course is intended to train safety managers, laboratory' staff, and related workers in the control of accidental injuries. The course pro vides an opportunity for staff members to be reapprised of the facilities and methods at their disposal to minimize injury in the laboratory. Administrative and organizational aspects as well as design and construction of laboratory equipment and facilities will be discussed. Methods of handling reagents, bio logical, pathological, radioactive, and other materials and specimens will be rev iewed. Animal care and related facilities, protection from extreme tempera tures, and waste storage and disposal are to be included. The trainee will have opportunity to investigate ventilation systems, clean rooms, diseases transferable to man, emergency aid, noise, and other pertinent subject matter. Inquiries may be addressed to Training Branch, Bureau of Occupational Safety and Health, 1014 Broadway, Cincinnati, Ohio 45202 or inquires may be made bv telephone to (513) 684-3287. Measures for Industrial Noise Control A five-day course on Measures for Industrial Noise Control will be co-spon sored by the University of California and the National Council on Noise Abate ment in Berkeley, California on March 22-26, 1971. This course is directed towards the practical steps needed to meet the requirements of the noise amend ment of the Federal Walsh-Healey Act. The course will deal with basic con cepts of noise and noise measurement, prediction of noise-induced hearing im pairment, the effect of noise on speech and work performance, and hearing con servation programs. Major emphasis will be placed on case histories of noise control measures and their effectiveness in various industries. Each enrollee will receive the 1967 guide on Industrial Noise issued by the U. S. Public Health Service and the 1966 Industrial Noise Manual of the American Industrial Hy giene Association. Advanced enrollment is required and may be made by individuals or com panies. The enrollment is $315. For further information please write to Con tinuing Education in Engineering, University Extension, University of Cali- ooog Fnhon Street, Berkeley, California 94720.