Document GKa6gNgJBkny4zGzR3KmYVGv4

FILE NAME: Caterpillar (CAT) DATE: 1943 Feb 28 DOC#: CAT062 DOCUMENT DESCRIPTION: Illinois Labor Bulletin - Wartime Operations Emphasize Industrial Hygiene Problems ofAsbestos Industry 1518.05 L ATBHOER I LB LUILNLOEITSI N STATE OF ILLINOIS . . . DWIGHT H. GREEN, Governor Monthly Publication of the ILLINOIS DEPARTMENT OF LABOR m w n s B. M URPH Y, Director Volume 3 FEBRUARY 28,1948 Number 8 WARTIME OPERATIONS EMPHASIZE INDUSTRIAL HYGIENE PROBLEMS OF ASBESTOS INDUSTRY Control Measures Have Not K ept Pace with Step-Up in Production Increased demands for war materials and for men to use those materials on the fighting fronts make it impera tive that workers on the production front be protected from industrial hazards. Although the number of workers exposed to asbestos dust is not very great, the potential harm ranks it with the most hazardous industries, because " asbestosis" is one of the most insidious and disabling industrial diseases. It is unfortunate that little attention was paid to this disease until twenv-five years ago when a number of deaths occurred. However, as a result of those deaths several extensive studies were made, and from these we have gained some knowledge of potential harm in this industry and how it may be avoided. Today, when we speak of asbestos, and other industrial health hazards, we are interested not in observing classical symptoms of disease, but in preventing the harm by means of engineering con trol. This article will show what progress has been made in controlling the hazards in the asbestos industry in Illinois and what remains to be done. In order to appreciate the importance of preventive measures in this industry we will consider briefly the dis ease-- asbestosis. Silicosis has been known as a serious lung disease for many years, but few people have thought of asbestosis as an even worse disease. What ma.kp* it worse is its insidious character, the fact that so m uch harm can be done before X-ray or other evidence can be found. and that the disease is progressive--the lung condition continues to grow worse even when the worker has left the offending environment. Therefore, medical examina tions cannot be relied upon to protect workers in the asbestos industry. Not only is this method useless, but thp a m o u n t o f h a rm __p o ssib le without visihlp pviHpnrp makes it a dangerous substitute for control of the dust. In one of the studies mentioned above1 the conclusion was drawn that workers exposed to less than 5,000,000 par ticles of asbestos per cubic foot of air would be unlikely to develop asbestosis. This value has been used to measure the potential harm in industrial environments, as well as the success of control measures. A sbestos In du stry in Illinois A large percentage of the thousands of workers engaged in the asbestos industry in the United States are employed in Illinois. Most of this work is on asbestos textiles and on pipe covering and other insulating materials. The In dustrial Hygiene Division of the Division of Factory Inspection has made extensive studies of the atmosphere iu several of these plants over a period of years. Until 1941, when war production caused a sharp rise in activ ities, there was evidence of gradual improvement in this industry. However, since that time it is apparent that control measures did not have the flexibility or capacity to take care of increased production, and the result has been high concentrations of asbestos dust and fibers in the fac tory air. Nor is this experience limited to the asbestos industry; in many other industries engaged in war pro- 1 " A Study of Asbestosis in the Asbestos Textile Industry," U. S. Public Health Service, Public Health Bulletin No. 241, 193S. duction we have found that poorly designed exhaust sys tems and other control measures are ineffective in taking care of stepped-up production schedules. The workers em ployed in those industries would have been properly pro tected if necessary improvements and expansion of exhaust equipment had been anticipated when new production schedules were considered. Because of the danger and insidious effects of exposure to high concentrations of asbestos dust, effective control measures must be adopted by this industry now in order that accelerated operations will not be accompanied by a corresponding increase in cases of asbestosis. Asbestos has been incorporated into a number of prod ucts such as protective clothing, brake linings, cements, roofing shingles, plastics, pipe covering and other forms of insulation, etc. This results in a variety of hazards start ing with the breakdown of the native mineral. On the basis of the plant studies made by this Division, the dis cussion of hazards can best be done by dividing the plants into two groups-- rigid products and textiles. yianufacture of Rigid A sbestos Products Most of these products are used for heat insulation in the form of blocks, sheets, or molded pipe covering. The first job is to break up the crude asbestos in a pan-mill, under rollers, or in an " opener"-- a series of revolving cylinders on which hooks tear apart the asbestos fibers. T a b le 1--D u st C o u n ts in M a n u fa c tu r e o f R ig id A sbestos Products (Most samples chiefly asbestos, others largely asbestos with silica, silicates and other dust.) i Date Stage of | taken operations : (month, year) Plant Dust count (Millions of particles per cu. ft.-air) Actual operation, control 5/41 B Preparing 5/41 B and 9/42 C handling 4 Bagging cement; good exhaust. 1 Mixing cem ent; good exhaust. 119 Crushing and bagging scrap ; over loaded exhaust system and poor housekeeping. 11/37 A 4/38 D 4/38 D 6/38 A 6/38 A 6/3S A 9/41 A Forming and 9/41 A building 7/42 B 7/42 B 7/42 B 1/43 A 1/43 A 26 Near builder ; good enclosure and ex haust. 15 Feed end of builder; fair enclosure and exhaust. ii Output end of b u ild er; fair enclosure and exhaust. 19 Near bu ilders; fair exhaust, floors wet. 22 Near bu ilders; fair exhaust, floors wet. 7 Near builders ; fair exhaust, floors wet. 122 Feeding asbestos to builder; exhaust not properly used. 104 Output end of bu ilder; most dust from feed end. 33 Feeding asbestos to shingle machine; exhaust system improperly main tained. IS Forming asbestos shingles; exhaust system improperly maintained. 44 Forming asbestos shingles; exhaust system improperly maintained. 32 Near b u ild e r; dust mainly from leak ing opener. 70 Rear of b u ilder; dust mainly from leaking opener. 11/37 A 7/40 A Finishing 9/42 c 9/42 c 9/42 C 49 Sawing pipe covering, 2 saw s; poor exhaust. 3 Sawing pipe covering, 2 saw s; good exhaust. 47 Sanding insulation block s; overloaded exhaust system, poor housekeeping. 127 Sawing insulation b lo ck s; overloaded exhaust system, poor housekeeping. 109 Turning pipe covering; overloaded ex haust svstem. poor housekeeping. 10 In dustrial Hygiene Division More dust is usually produced by the opener than by the pan-mill. The prepared fiber is moved to storage either by con veyors or by trucks. Considerable dust is created by shoveling the fiber into bags or trucks, one air sample showing more than 30 million particles per cubic foot of air (see Table 1). The next step depends upon the product to be made. The fiber may be spread out on mechanical conveyors and sprayed with an adhesive, or it may be mixed with vari ous fillers in batch mixers. In practice, these batch mixers have been found to be well controlled by enclosures which are exhausted to remove the dust before it can get into the air Avhich the workers breathe. The same cannot be said for hand spreading on conveyors: dust concentra tions as high as 122 million particles per cubic foot of air have been found at these operations. While our chief con cern in this discussion has been exposure to asbestos dust, it should be noted that when the asbestos fiber is mixed with the various fillers and binders, workers may be ex posed to the added hazards of free silica dust, as well as a number of silicates. A binder widely used in this industry is sodium silicate (water glass), which is strongly alkaline and irritating to the skin. In building and moving the wet insulating prod ucts to the drying ovens, very little dust is created but the direct hazard from this operation is skin irritation. Handling of the dried asbestos blocks or pipe covering can create a serious dust condition unless the proper ex haust equipment is provided. Insulating blocks are brought to size by sawing on band saws or table saws and by sand ing and turning. Rigid pipe covering and pipe are usually cut to length on band saws. Wherever tubular material is sawed exhaust outlets must be provided both for the dust coming off the outside and inside of the tube. Good housekeeping is very important, in addition to proper exhaust equipment, if real control of the air-borne dust is to be attained at sawing operations. It must be remembered that what we are interested in controlling is the fine par ticles and filaments which can get down into the lungs. What makes the problem difficult in these operations is that exhaust ducts frequently become clogged with the coarser material and large quantities of waste accumulate on tables and floors where they can be ground into fine dust and find their way into the workroom air. Only a rigid pro gram of maintenance of exhaust equipment, coupled with regular cleaning up, will assure control of the dust hazard. Before it goes to the shipping department the sawed material is dusted by brushing or by compressed air. The former of these methods can be more easily controlled-- provided the brush is equipped with sufficient exhaust. Where pipe lengths are stacked endwise and air blown through the lengths toward an exhausted enclosure, the ventilation requirements are very high for adequate control of the dust. Turning and routing of small size pipe coverings from solid blocks of insulating material usually creates very dusty atmospheres. Wherever these operations have been observed the attempts at dust control have been unsuccess ful, and it is a difficult ventilation problem. One solution appears to be forming these coverings on the appropriate sized mandrels. Along with the manufacture of rigid materials some concerns mix and bag asbestos cements. M ixing and bag ging create no problems which have not been solved in other industries. Proper enclosures equipped with ade quate exhaust will keep the greater part of the dust out of the workroom air. The results summarized in Table 1 show the hazardous air conditions found in four plants manufacturing rigid asbestos products. Plants A and B both have instituted some control measures but the results indicate that more work must be done to bring the dust concentrations below the tentative safe level of 5 million particles per cubic foot of air. It is also clear that Plant C which has the poorest control equipment has the most serious dust conditions. M an ufacture o f A sbestos Textiles The principal products in this part of the industry are asbestos cloth, twine, tape, woven brake lining, and woven gaskets. In order to make this variety of products it is necessary to follow the original separation or " opening' of fibers with the following operations: carding, spinning, twisting, spooling, winding, and weaving. In general, it may be stated that these added operations in the textile manufacture create more difficult problems in dust control than those in the manufacture of rigid products (see Table 2). T ab le 2--D u st C oun ts in M an u factu re o f A sb esto s T e x tile P r o d u c ts--P la n t A (Dust in these samples was practically all asbestos) Stage of operation Date taken (month, year) Preparation 4/40 4/40 4/40 9/41 Carding Spinning Weaving 1/43 1/43 7/40 7/40 9/41 1/43 1/43 1/43 7/40 7/40 9/41 1/43 1/43 7/40 7/40 9/41 9/41 9/41 1/43 1/43 1/43 Dust count (millions of particles per cu. ft. air) S 35 15 70 32 07 37 44 219 32 116 77 6 11 20 39 25 4 10 4 3 11 55 19 61 Actual operation, control Near Creighton opener; fair enclosure, poor exhaust. Between 2 p ick ers; enclosed but not ex hausted. Between picker and reclaim ; p artial enclo sure, no exhaust. TVBlowing asbestos-cotton m ixture ; exhaust ed. but most dust from shoveling into hopper. Shoveling and b ag g in g ; no exhaust. Near picker; exhaust enclosure leaking. Center of carding room ; % of cards en closed and exhausted. Center of carding room ; % of cards en closed and exhausted. Rough carding asbestos-cotton m ixture ; im proper exhaust. Rough card : improper exhaust. Finishing cards: improper exhaust. Finishing cards ; improper exhaust. Mule spinning; no exhaust. Ring spinning, experimental ; no exhaust. T w isting: high humidity. T w isting; high humiditv. Mule spinning ; no exhaust. Middle weaving room, S. end ; high humiditv. Middle weaving room, N. end ; high humidity. Weaving blankets, card room ; exhaust tem poor!v maintained. Winding bobbins, weaving department high humidity. Weaving tap e: high humidity. Weaving blankets ; preparation room. Winding twine, weaving d e p t.; high humiditv. Winding broadcloth, weaving d e p t.; humiditv. sys ; high (Continued on page 22) 11 Prospective Building in Illinois Cities T a b le 4-- S u m m a r y o f Ja n u a r y 1943 P e rm its by T y p e o f P ro p o se d B u ild in g a n d G e o g ra p h ica l A rea To reporting cities Type of building Num ber projects Permit valua tions TO TA L-- ALL TY PES OF BU ILD IN GS-- 495 $1,602,197 New residential buildings ................... 96 Housekeeping buildings One-family dwellings... 87 9 600,500 375,500 225,000 N ew n o n -r e s id e n tia l b u ild in g s .................... 57 4 G arages, private____ ______ - .......................... 37 3 Sheds, poultry houses, etc................................. 26 4 1 288,962 209,800 8,952 11,500 27,000 2,280 21,430 8 ,0 0 0 A d d itio n s, e t c ... .... ...... ............................... 342 Additions, alterations, and repairs Residential buildings ......................... 194 Non-residential buildings............................... 98 Installation perm its.............................................. 1 50 712,735 94,665 580,841 37,229 Chicago area (76 cities) Total Num ber projects 257 72 63 9 43 2 27 3 1 5 4 1 142 66 65 11 Perm it valua tions $1,223,343 523,300 298,300 225,000 105,008 32,000 5,953 11,500 24,000 2,125 21,430 8 ,000 595,035 59,548 507,062 28,425 Chicago Num ber projects 132 21 12 9 26 2 13 3 3 4 1 85 28 48 9 Perm it valua tions $899,457 277,800 52,800 225,000 77,288 32,000 2,458 11,500 1,900 21,430 8 ,0 0 0 544,369 33,885 482,109 28,375 75 Chicago suburban cities Num ber projects Permit valua tions 125 $323,886 51 245,500 51 245,500 17 27,720 14 3,495 1 24,000 2 225 57 50,666 38 25,663 17 24,953 2 50 Downstate area (105 cities) Num ber projects 238 24 24 P erm it valua tions $378,854 77,200 77,200 14 183,954 2 177,800 10 2,999 1 3,000 1 155 200 117.700 128 35,117 33 73,779 39 8,804 ber 1942. All three types of construction showed decreases when compared with January 1942. New residential building- increased 30 percent, or from $59,568 in December 1942 to $77,200 in January 1943, new non-residential building increased 344 percent, or from $12,739 to $183,954, but additions, etc., decreased 76 per cent, or from $483,972 to $117,700. One large project, estimated to cost $110,000, was issued for an industrial building to be erected in East Peoria. Twenty-two of the 105 cities reported higher permit valuations in January 1943 than in December 1942, and nine, higher permit valuations than in January 1942. Ten cities have been added to the Downstate area, in creasing the number of reporting cities in this area from 95 to 105. Industrial Hygiene Division (Continued from page i i ) A fter leaving the openers the asbestos fibers are mixed with cotton; this is done either by hand mixing on the floor or by feeding the two kinds of fiber into a " willow" and the mixture is conveyed to storage. Both methods can create very dusty conditions and require proper enclosures and exhaust to prevent the operation from constituting a serious health hazard. From storage the mixed fiber goes to the cards, a series of fast moving steel brushes. For the coarser type of prod uct, such as coarse braids, a single card does the whole job, but on finer textiles cards are usually run in pairs with automatic transfer from the primary to the finishing card. This operation usually creates the greatest dust contamina tion in the entire process and presents a special problem in control because the quality of the product can be changed considerably by too rapid a movement of air across the machine. The high dust counts found at this operation indicate' that the attempts at control -- large enclosures around the cards with exhaust through the floor or ceil ing-- did not even approach successful dust control. The amount of air required for adequate exhaust on these en closures is so great that in practice proper control will more likely be achieved by close housings, using less air. Spinning is done on ring and mule spinners, the former being smaller and easier to control by enclosure and ex haust. Twisting frames also create asbestos dust by fray ing the threads. In twisting operations the dust counts are usually in about the same range as those obtained near the spinners. When asbestos is twisted on wire, as in the manufacture of brake linings, the dust concentrations are higher than when asbestos alone is twisted. For ade quate control of twisting, individual exhaust outlets must be provided for each strand. Weaving is another operation which creates consider able dust and it is obvious from the dust counts in Table 2 that the increased humidity in the weaving department is not sufficient to keep the dust in the air down to safe levels. Winding is done in the same room as weaving but seems to create much less dust. Wet methods have helped to control the dust in weaving operations in other states, but in Illinois reliance on high humidity alone has failed to control the dust. Apparently, where high-humidity-dry weaving is done the enclosures and exhaust will have to be greatly improved before the dust concentrations can be brought down to safe levels. The conditions revealed by the studies in the asbestos industry reflect what is happening in so many industries today under wartime schedules. Attempts are made to increase production without taking into account the nec essary modifications in the control of health hazards by ventilation and by other means. The result is increased accidents and lost time due to industrial diseases, which means lower, not greater, production. The products manu factured by the asbestos industry are most essential for the war. To get those products made in sufficient volume and to keep asbestos workers on the job at full efficiency will require immediate improvement in control measures throughout this industry, and assurance that these controls will keep pace with the volume of production. The Industrial Hygiene Division welcomes discussion of the material presented in this article by those interested in the prevention and elimination of asbestosis. 22