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FILE NAME: National Safety Council (NSC) DATE: 1935 Oct DOC#: NSC239 DOCUMENT DESCRIPTION: Transactions of the National Safety Council - 24th Annual Safety Congress - Excerpt ^ n i TaAMUCnOMt al Ae T u b a r ti I n n i Safety Congress. *' ftaSbml Ade* CawncS, 1% are pritlrind ill t m vnhwisi Thft w lw i, A tS iA chmAh Aa emanai aaashmb A* spettai mbject aseakam and 'A* XaAafehl Sodim aaaaltnn ' ft ft sm ilim itil f t . * 0 ostane nmtafty A* M f t i r f A i Stmst sad Highway Tnfie Sectfto, At CUM ItaraHwn BHMiPMi w Dv c n sn y m m n m tow wwwuNdl toy M B J BMQINM QSWW WWW It WQfUl WOtll 10 W lnlP W i COpHI OK Q W ASVIHMMm vO ABVtWQKKk SOKWHhKSHHI 'OBMSKV Ch VI ACDWBBRWW 0 NSW* vftory yositfcm h o n q r n t e practical tm of them fo r t t fi m iw po rp osss. Vr wm i alAus^c ImumamU o--t n^owmwho o l--oti--v-atzMuii ocAohp^se^snob--n----i-o--u--o--w- i1o--v--<--p-m---iHiiy pnooo JJWMOA quoted: O ne to tm copies o f A e larg e volume, $1.90 each; eleven copies and ovat, $1.25 each; copies of A t *w *^*11volum e. 50c r****** T m A C CO RD A N CE w ith th e plan o f publication followed fo r A a p ast several . x y e a n A e T tenaactione a n pubUshed again th is year a s a condensed record o f A a proceeding s a t A s N ational C ongress. T he papers of each session or division o f A e C ongress have been edited carefully to elim inate extraneous m at te r and to abbreviate th e less essential portions because of apace lim itationa. In other w ords, the m aterial herein presented is not a verbatim report of all the speeches presented a t A s Congress, b u t rath er an abridged version, m ade aa com pact as possible, y et w ithout any injury to the technical aspects of any address. T he original m anuscripts are on file in the library of A e N ational Safety Council, w here A ey are available for additional reference. In several cases, w here illustrations w ere sent by A e speakers to A e Council, A rne also are on file. T he N ational Safety Council a t its C ongresses series to elim inate from dis cussion m atters which are n o t pertinent to the aim of the C ongress o r which are contrary to Council policies, but it cannot accept responsibility fo r the views expressed either in A e papers presented o r in th e discussions based upon A s papers. NATIO NAL SAFETY COUNCIL, INC. 20 North Wacker Drive, Chicago !' .V' M O K N IN G S E S S IO N O c to b a r IS , 1935 The session was called to order bgr lie . W . Dean Keefor, director. Industrie! Division, National . Safety Council. D r. C E W atson, newly-elected President of The National Safety Council and Medical Director, American Telephone and Tele fVmgpRI \^SMpflHyFp ^HB^F mOW >^KJ% fnCHQBQe Present and P ros pective Occupational D isease Legislation jr P. ROBERTSON JOHNS Asaodntioii ol CaanMtp and Sntatjf Snaentivea New York, N. Y. the prevention of diseases ree, a community problem, the state ought to do its part toward the occupational diseases, along with alt others. The ptM ic health authorities shouldituuddy tdhie causes of such dis- tk d r prevalence, virulence and the means for their prevention. They should advise as to such means of control, and, as a last resort, appeal to legislatures for power to order compliance with their roles. Statutory regulations for prevention, emanating from other sources, such as are common in `lab o r ' o r "factory" laws, have too serious drawbacks to be efficient. They are apt to be inflexible and quickly become "out of date" ; and they are too apt to be perverted for the establishment of fictitious bases for wasteful and demoralizing damage-suit litigation. Scientific bureaus of occupational hygiene, under direction of public health authorities, are the best public instrum entality. Efficient bureaus of that character are now to be found in several states; but, generally, such public health organizations are inadequately manned and equipped. Therefore the prim ary need in occupational disease legislation is for measures to improve our public health services.* Fjwpha should be placed on prevention, not merely because "an ounce of pre vention is w orth a pound of cure," but because public measures for the assurance of relief to victims are perilously susceptible of being so perverted that those affected will tend to rely upon and abuse the protection afforded as a substitute for, instead of as a supplement to , m en s for self-protection. * Expert opinion now calls strongly for the entire elimination of employers liability for "damages" foe occupational injuries--by disease as well as by accident--based upon negligence. T hat remedy is too uncertain in operation, litigious, demoralizing and w asteful; it furnishes relief to too few of the victims unless it be so liberalized as to be grossly unjust and financially perilous to employers--and thereby harmful to ndustry and aO dependent upon industry. I / from ill-health among workmen are prim arily subjects for self-providence or for "social insurance"--for "sickness insurance" to help out during brief illnesses, and far "invalidity," "old age" and "widows' and orphans' " insurance where illnesses o r infirmities result in long or permanent disability or untimely dealth. The cost f f these insurances against h e common misfortunes of life cannot rightly or expediently be imposed wholly upon industry, but needs to be distributed somewhat in proportion A t twmfits m a t fce graded, more or l y for M ae relatively small proportion of the injuries and physical a ,l1" " abject that it is reasonable and practfcableto impose the faH ___ _________ ____ ______ country and Lathi America it has been extended indefinitely further to cover "all indusivehr all injuries to health "hrin* out of and in the course of the employment" or all "occupational diseases," undefined, "arising out of the employment" In this country there is coverage of in principle between ~injoi tty ought to be liable for both classes of injuries on the same terms and conditions. This contention is fallacious. The fundamental principles of the compensation law are that industry shall be held responsible and liable to compensate for the losses from those injuries only which are caused by "trade risks", resulting from employment and which die employer can control; and that die liability for such risks shall be suffi ciently well defined as to be insurable at practicable and equitable rates, fixed in advance. The standard compensation laws have been framed to carry out those prin ciples in application to injuries by accident. But the factual conditions relative to injuries by disease are so different from those relative to injuries by accident as to necessitate different treatment. The crucial difference between accidents and diseases is the time factor. An accident is a sudden event, happening at a definite time and place. Generally the causal relation between the employment and the accident and between the accident and the resulting injury can be traced with reasonable certainty. Generally the employer is automatically identified. And there is a clear-cut event from the date of which thne-limits on notices, claims, etc., can be measured. In contrast, many diseases attributable to occupational risks are of slow contraction, and may be of equally slow progress to harmful results. In silicosis there may be an interval of as much as twenty or thirty years between the first exposure and disability or death. In the meantime, many causes for disablement or death, other than the occupational disease may have operated. Often it is a m atter of extreme difficulty to determine whether disability or death really has resulted from an occupational disease or from other causes. Medical diagnosis of the mere existence of a particular disease is often uncertain; yet for the proper operation of compensation for occupational diseases it is essential to obtain true medical diagnoses, not merely of the existence of the disease, but also of its causes and consequences. A further difficulty is that, where the disease is of slow contraction, it _may be contracted by a workman under several different employers or insurance carriers. In such cases it is essential .for the protection of the workman that some one existent employer or insurance carrier shall be directly liable for the entire compensation. That is a highely vicarious and harsh liability to impose upon an employer or insurer --whether or not accompanied by a right to claim contribution frotn earlier employers and insurers--and, in all fairness, should be subject to strict limitations. Moreover there is a difficulty incidental to the provision of new insurance for compensation for such diseases of slow contraction as silicosis. Under such conditions, the liability imposed upon the employer includes a liability for disability or death in the future; in other words, a liability, not merely for future risks but also for the cost of a volume of physical impairments already incurred though the liability therefor is not yet matured. In insurance parlance, these are termed "accrued liabilities." Such accrued liabilities, under a law newly imposing a liability to compensate for silicosis, would, it ia estimated, in a state such as New York, aggregate many millions of dollars. This cost is additional to losses from current risk s; and how to meet it and how to fix reasonable charges for insuring it is a complex financial problem. i t # 1* Ills iSlfpS ; qjft: - .A j BBS!: f | l l 119 M R mm' d. U fa o t cowpensatkn, rebm n snssrs m t nra - -JZ3L g |g f tp * otruasliim pncesa m * *.mrS*ch*M M *k' ^ T ~ o u t r f W a of Mta>. The HWrWow toe such ooverage should be peorisions of imp applicable to compensation for acdKtkms shook! beooastanlty emphasised. The problem . ...___ it relatively M e with reference to those recognised in the older i ~mu nil I "j" ** laws, w sodt diseases are ----- \ of quickcontraction and non-progressive. B at it is difficult in to jjp fi p o p o m diseases of slow contract as ffieosls and asbestos--- as being truly MoccopotionaLN Fortunately, however, there for o ar guidance hi some of the foreign compensation laws, . "all inclusive" coverage in Connecticut, Massa- California is helpful with lessons of faults to avoid. opinion, a law for the compensation of occupational diseases should contain n i aouowng fm c t' 1. Diseases to be made "compensable" should be distinctly specified--by listing in a "schedule" o r otherwise. They should include all those diseases, but only those, to he found in die state, which, according to prevailing medical opinion, can be traced, in individual cases, to origins in "trsde-risks"--i. t., risks, not of ordinary life, but created hy special practices o r processes in industrial occupations. Z There should be a special regime for expert adjudication of medical questions in occupational disease cases. 3. There should be definite periods of exposure required as a condition to the right to compensation for various occupational diseases; die time within which, in order to be compensable, disability or death must follow exposure should be lim ited; and cases resulting from exposures prior to the effective date of the compensation coverage, o r hi industries wholly outside the particular state, should be excluded. 4. Prom pt notice either of die first manifestation of the disease or of disablement --the time of such event to be determined as a medical question--should be strictly required: and every presumption should be against the validity of a claim not made as promptly as practicable! 5. In case an occupational disease merely aggravates, prolongs or accelerates disability o r death due prim arily o r proximately to a non-occupational disease or infirmity or, above all, to old age, the compensation should be reduced to be propor tionate to die degree to which die occupational disease contributes to the disability or accelerates death. 6. The employer, as of the time of the workman's last substantial exposure to hazards of the disease, and die insurance carrier then on the risk should be liable for die entire compensation--with or without right to contribution from earlier employers and insurers. But all such liabilities, whether directly for compensation or for con tribution to the compensation payable by others, should be subject to brief time limitations. 7. In incurable diseases, especially silicosis, the obligatory medical benefits should be specially limited in time and kind. 8. In silicosis and other diseases of slow contraction, there should be special provisions for limited compensation to workmen laid off before actual disablement, with die alternative, under some conditions, of waiver of compensation by such work men for aggravations resulting from being allowed to continue in the hazardous occupation. ... ... 9. A law newly imposing liability to compensate for silicosis and other diseases of slow contraction should leave a substantial interval for preparation between the Amir of its enactment and that when it shall take effect; the compensation for such should be specially reduced and limited below what would otherwise be appropriate until die "accrued liabilities" are worked off. 10. Compensation for occupational diseases should be insurable separately from compensation for accidents; and, in the initial stage, a t least, of a regime of com pensation for such diseases as silicosis, the rating practices now imposed upon insur ance carriers need to be radically modified. itiis wuoataiH Of J -- m :amBmu *M 0 BfWlMCffi CTPtpl OH tDC W AbmkM | nv8i 1 ^ tMNfliiHlici Id prevention, there sre ttfil tone p u cticti to be decided upon in t RfM K Of for oral dueaaes about which there F ar example Sacha i wm practically compel d m ` lo diacnaa an the ailing o r w ing agunrt all ..... .. , ' and robust T hat ... __ o..c...o..e.t.t.f.pDfte in th e ocenratioral d b a o e hayards are grant.' But is it M n U t otherwise Again, ap ideal common to those of as who emphasis* prevention is to r equire A t prompt m oral front exposure of w f a s tn manifesting the first symptoms of an occupational disease. But for the elderly or skflisd w r i n s A e loss of his trade-job a n y bo worse in every respect than the draper of ontthuiing Ms exposure. How then should such cases be defined and treated and how shoidd die law be framed to effect or induce such treatmeat? Political impatience is the chief obstacle to a just and equitable settlement of the occupational disease problem. If those thoroughly informed as to this complex sub ject who have sincerely at heart the welfare of workers could be delegated the au thority to devise a solution, some progress aught be made. But when political propaganda is injected into the situation there is little chance for an adjustment satisfactory to all concerned. The greatest need today is the divorcement o f occupa tional disease legislation from politics or political considerations. "i . Soane Practical Considerations in D ust Control By J. J. B LO O M FIELD S anitary E ngineer, U nited S tates P ublic H ealth 8 erv k s, W ashington, D. C. The prevention of occupational diseases due to die inhalation of industrial dust is prim arily an engineering problem. U ntil recently, however, little attention had been devoted to die control of dust, accounting for die paucity of fundamental data on the subject. The consequences of die neglect to furnish adequate protection from dust hazards are now being felt, and the cost is becoming a serious drain on industry. It is now well established that exposure to certain kinds of d u st such as those con taining considerable amounts of quartz, has increased the morbidity and mortality rates from respiratory diseases; while metallic dusts, such as lead and its compounds,' have been associated with general systemic poisoning of workers. It is obvious, therefore, that any serious attempt to control the dust hazard should, in _time, result not only in die improvement of die health of workers, but also be of definite economic benefit to industry. The benefits of a preventive program in the field of accidents are well known. Industry is fast realizing the need of a sim ilar preventive program with respect to occupational diseases. Evaluation of the D ust H azard The first step in the evaluation of the dust hazard is the determination of the occupational exposure to the dust in question. A typical example of such a study may serve to clarify the methodology involved. Table 1 shows the various occupations in a granite quarry and the number of workers employed in each occupation. D rillers are the only persons using pneu matic tools, known to produce considerable quantities of dust. In other words, 38 per cent of die quarry personnel are drawn to be exposed to a potentially dangerous dost hazard. The occupational analysis at odee indicates that the dust investigation % I xn : tf at f e w .............^ - 'V . M S * I IS k *` m Sht ' ' ' n i ^ 'j r t k w M r .............*.......................... 37 ' %J^sM^ahnWHpn'^^^p^MBmBmM#nya'W^i^yWBvi. l 7 1 12 1 I ___________ ____________ _________ 1 Qnm operator ........ 1 Patrick men ..............................-......................... 24 Mneksrs .............................. 24 Wf- f r --Offc. ................................................................. 6 Tool bm rs.............................................................. 2 W aterboys .......................................................... 1 Iffi^riw h^ .................................................................. 3 Air-liue repairers .................................................. 1 npc nucrs . * Total............................... ~M2 Ik k h 2--Occupational Data Kxpoaors oI Granite Quarriers Occupation Leyner d rille rs ............................................................. R ag and jade-hammer drillers (q u a rry -b o le )........ Plug: drillers (y a rd ).................................................. A ll other w orkers.. . .(................................................ Number in each Occu pation 17 37 88 Dust counts in millions of particles per cubic foot of air. W eighted Average 144.4 112.1 36.9 53 should especially concern itself with these workers. The next step involves the determination of die occupational dust exposure. Table 2 shows the results of such a study _ I t is apparent in this table that the drillers are exposed to high dust concentra tions, especially the Leyner and jackhammer drillers working in the quarry hole From a further analysis of the occupational dust exposure of drillers it is possible tn M e" which activities are responsible for the d u st For example, experience has taught us that the various activities comprising the processes of most dusty occupations are usually associated with dissimilar dust exposures. For this reason H is sfwriat to estimate die amount of time spent in each activity in any one occu pation and to determine die dust exposure for each. Table 3 shows the results of such a study in die case of a Leyner driller. I t will be seen that a Leyner driller has five different dust exposures. A differ ential analysis, as presented in Table 3, yields several valuable findings. First, it m Hm me to obtain a true average dust exposure for workers engaged in the occu pation of Leyner drilling. (In this case the weighted average is 144.4 as contrasted with 213.4 millsoo particles per cubic foot found during drilling operations only.) SCBoml, it enables one to determine which activity, or activities, contribute most to the Activity Average d art OfM UK in ndOkiM of Number of p n tic b par cubic hoar apart in foot of air (a ) each activity fb ) D riH m g.......................................... 213.4 4 Chmgrng d r ills ............................. 9M 1 W rtchb* k ills...................... ....... 8.0 2 B n u d i n f .......................... . ........ 6.0 X Blowing off holes................. ....... 1,085.0 X Particle-hours in mfllkms par cubic foot (a X b) 853.6 9A 16.0 43 2713 T otal............................... 8 1,1553 1,1553 particle-hours in millions per cubic foot 8 hours 144.4 million particles per cubic foot dost hazard. It is evident that the practice of blowing off holes by means of inserting a compressed air line into each hole is attended with a great amount of dust; and though this activity lasts but 15 minutes o f the 8-hour working day, it is responsible for 23 per cent of the total dust exposure. It is evident that 23 per cent of the Leyner driller's dust exposure may be at once eliminated by prohibiting this practice. And lastly, such an analysis indicates the necessity for devoting all one's efforts to the removal of dust during the drilling process, since this activity accounts for 74 per cent of the total dust exposure, although a I-eyner driller spends but one-half of the working day at his drill. So far we have dealt with an industry in which the workers, as a rule, do not change their occupation. Often workers have had several occupations, either in the same industry or in several different kinds of establishments. If the worker has been employed in various occupations in the industry, it is a simple m atter to determine his total dust exposure in that industry. This is important from the viewpoint of correlating a worker's dust exposure and his clinical condition. A typical example is shown in Table 4. T able 4--T otal O ccupational D ust Exposure of an A nthracite Coal W orker Occupation Slate picker ........... Patcher ................... * Mule driver ........... Miner's la b o re r---M in e r...................... Section foreman . .. Number of years in each occupation ........... 2 ........... 2 ........... 3 3 ........... 15 ........... 5 Dust concentra tion in millions of particles per cubic foot 380 71 71 480 480 7 Millions of particleyears pet cubic foot 700 142 213 1,440 7300 35 T o tal............... ........... 30 9,790 9,790 millions of particle-vears per cubic foot -- 326 millions of particles per cubic foot 30 years In Table 4 d ie w orker's occupations are arranged in the order of employment, the last one being his present occupation. It is obvious that had one considered this occupation only, the dust exposure would not have yielded a true state of affairs. k> U oot 790 foot W ft1 ,f 7f i 123 g :with tha n clinirol umber of i . ,,... r t t n a e k f M r l at a fafcr ntim ffiiof a worker's te* i --ty ii fa justified by f l t t e t tel* with the dinko-roentgenological cm! that there i more to engineering dust tu n m * than the taking i and their analysis. Owing to the fact that the making oi test (todies fa n> id(y bring adopted in industry, it ha teemed necessary to emphasize the importaaft factors ia Rich investigations. Altooujto me makbig of test counts, rr r, fa n et difficult procedure, the collection of am t samples in industry and their proper Interpretation should be done by a thoroughly trained investigator. The examples Just gteen stum the value of this technic in the subsequent steps to be taken in toe im iw oi k wmmam one o iu ra. Q a i n l D ost C a a m l iig*ii*dh The selection of any method of dust suppression will depend primarily upon its effectiveness in reducing a given hazard and its adaptability. A large percentage of reduction in test does not necessarily indicate that toe method used is efficient, unless the redaction has actually been sufficient to bring the exposure below toe safe limit, and does not interfere with the industrial operations involved. In general, there arc four methods of dost control: (1) substitution of nondust-producing or harmless sub stances; (2) isolation of toe testy operation; (3) wetting the dust at its source; (4 ) local exhaust ventilation. These methods may be supplemented by personal respiratory protection. The first method has a limited application. One example is the use of a non silica parting compound for a silica compound in connection with the making of foundry molds. Table 5 stem s that although the use of parting compound, in this particular study, only necessitated an exposure of 54 minutes of the 540 minutes of a (Holder's work day (10 per cent), actually this activity accounted for approximately 58 per cent of the molder's total exposure. It is obvious that the employment of a parting compound, which is not as harmful as one composed of free silica, will lessen the dost hazard in this instance to a considerable extent T able 5--D ust Exposure of M olders Activity Average Dust Exposure in Millions Time of Expo of Particles sure in minutes per Cubic Foot 00 (b) Use of Parting Compound... 54 Remaining tasks in molding.. 412 Pouring- ................................. 58 Dumping molds ("shake-out" ) . . . . 16 63.8 4.4 . 3.1 32.5 ParticleMinutes in Millions (a X b) 3,445 1,813 180 520 T otal................................ 540 5,958 5958 million particle-minutes 540 minutes 11.0 million particles (per cu. ft.) In the case of abrasive cleaning with steel instead of sand, we have the example of the substitution of a substance involving a lesser dust exposure as well as the um of a m aterial not as toxic as sand.*,, Table 6 shows the improvement effected by A! type of substitution. N ot only is the dust concentration reduced from an average o f 969 to 155 million particles per cubic foot, but the potential exposure to quarts dust is fimimsbed from 42-99 to 3 per cent i* ? 'I * *;* * * * :. 1S5 o fQ o v tt 4M to m e w e ; 'o rto * ! At'i la Me -- n , dur- wfch lo ir Ii M Wwm'iVLMgH-i WM NHRIL XmH*emcmmvl MmOBmHqAnnLmdmaItWombmyttm14wuRdwrR i w- B O M d m toe emptied m maltcrfde iron fauudrieit mpeeim grfudtos m 4 kmMNnn^fm| 'AiiaaJfeala nR mrO^lt Cn^O----C 09* P erfuse dm beet cxunplc of umlation of I dusty process ie the abrasive d em ine room. Thie oowpictcly enefoeee t hemrdone peooese end exposes only the faluter who ie generally equipped with i protective helmet. The room in slso exhausted, which farther reduces the dost concent ration. Proeemee which are isolated require gtwd vcouuidob. u m c r tn u n p ic f oc ivcmsoob s it cue svKJfnsttc iw h o o k to t lo re itw cleaning, tumbling barrels, and batch-mixing room* found hi some pottery establish- The third method, perhaps the oldest known, is the practice of wetting the dust at Hs source. Io Table 7 an example is depicted in connection with the drilling and loading of rode in anthracite coal mine operations* It is apparent that a tremendous redaction in dost has been effected by this method. However, as already pointed out, unless a particular method is attendant with a reduction of the dust to a safe lim it it cannot he 'considered successful. In the present instance, the workers engaged in drilling are still exposed to unsafe concentrations of a highly dangerous dust and the more positive method of controlling the dust in drilling operations by dust trap would be indicated. For drilling and loading operations involving an exposure to dusts less toxic than those containing high amounts of free silica, as in the case of coal or certain talcs, the reduction shown by the use of wet methods may be considered effective. Table 7--Contrasting "Wet" and "Dry" Methods of Rods Drilling and Loading Processes Average dust count in millions * No. of of particles per cubic foot Samples "D ry" -W et* D rilling Loading The fourth method--exhaust ventilation--is perhaps the most effective, and one with tile widest application. W e cannot discuss here the details of the theory and design of local exhanst systems, except to point out there is a real need for more fundamental studies of the tyne conducted by DaltaValle with reference to the design of local exhaust hoods, which he has presented in Public Health Bulletin 217. Th* work of H atch and his colleagues* on the control of the silicosis hazard in the hard rode industries is another example of a scientific approach to the dust elimination ifraM f con hi mnet. lus */ Preparation of coal... 24 380 w m v cow isa empty csve fw im m in hauligeway*. Wet breakers reduce chat counts ai shown. * T h t lo w ra n k I* U N tiitad with the baad loading oi wet coal while the higher average U b u t t am the head loading of dry coal. I t is apparent tin t there are no set rides for the mechanical protection of workers from the industrial dost basard. Specific conditions in an industry, o r a plant, will determine the type of protection to be employed. The present discussion has empha sised the importance of approaching the problem from the standpoint of the occupa- tiOBB] COCpOMMVw Studies in representative plants of an industry often reveal the various methods which may be employed in controlling the dust hazard. The follow ing two examples indicate the value of such investigations. Table 8 indicates the various control measures which were found in use in the anthracite coal mines investigated in the study referred to earlier. Although no single mine practiced all of the control measures shown in this table, by an occupational study in several representative mines it was possible to show that methods are not known mid practiced for the elimination oi the dust hazard in this industry. Another am ide is indicated in the results of a study now in progress in connec tion with mercurialism among workers in the hatters' fur cutting industry. Table 9 shows die exposure to mercury dust and vapor of some of die workers in this industry Tahla --Expoeare of H atters' For Workers to Mercury Dust and Vapor Under Controlled and UnoontroUod Conditions Occupation Total M ercury Exposure in M illigrams per 10 cubic meters Uncontrolled Controlled Blowers ........................ .................. 4j6 .................. 72 , # C utters ........................ ............... 4.0 1.8 Sorters ......................... ............... 3.8 U 12 C % r ............... ZS 0.6 ............... L5 OJ Method of Control None practiced Local exhaust venti4l#ation Segregation f t I1 Si 5 * !5 fT S t# S * S i1 '** r a m i w 9 .IMPE* HSWU 'g te tfle in find a plant in i ` Emm v m i uR i . gm w m g^K M il U fact; OMiMiM a n d -tte tfi! M u te of *Md oxide m tm u cto rc appear to id ler no means of dnst SM cM ed. In Mcb cm h it UiUsr tewhnmewrwemfmomr'UeSMneVcWe>eWseSrSv^ tUoHWbinunrftaUUfna^Phfilttime^Wt . ., _ p tra w i rcpwMory y v o n c m ocvictf w nrvivm ms o p o M t to mo xnsiMni tMCO of the lu sts present These devices consist of serious types of suipinlBf% msshe, mmS Imhy t i , 19 linpOnMIi tO xKHu B HMM MO M B M tSSO <Jt pcrvOINU PWIBCiWI aOTvOCS Botsusc s worker cewiot with comfor t w esr e nsisk o r h t e c t continuously, such devices m o t be employed interm ittently. Their use is p sc rslly extended to those operstions where au other methods have failed o r st^pplcOBCBtiuriir So jhjjOg ss So storase battery repair where the exposure to small amounts of lead breathed is inKwrn fa he detrimental to health. f t should be pointed out that the U . S. Bureau of Mines is equipped to cooduct approval tests of respirators used for protection against various dusts and fumes (Schedule 21). These tests are conducted against the dost for which the device is to he used and are rated, not on an efficiency basis, but on the quantity of dust which actually passes the respirator. The results of a study of masks or helmets of the positive pressure type, made during the sandblast investigation conducted several years ago by the Public Health Service in cooperation with the National Safety Council,' showed that the only practical safeguard to the worker inside die sand blast room was to provide him with a mask or helmet of the positive pressure type. In studying the efficiency of such devices it was found that a relationship existed between the amount of air supplied to the helmet and the concentration of dust inside the helmet during blasting. To determine the optimum air volume to be sup plied to such protective devices, it was necessary to obtain dust samples from inside the helmet while varying the air volume, at the same time maintaining the dust con centration in the sandblast room (outside the helmet) constant. The positive supply of 6 c a ft. of dust-free air per minute will protect a worker under the operating conditions now in practice in sand-blast rooms. The ultimate criterion of protection, however, is the result of dust determinations of the air within the helmet, that is, the, air actually breathed by the worker and not the volume of air supplied. Too much emphasis cannot be stressed on the necessity of maintaining in good order the personal respiratory devices for the protection of die worker against various toxic dusts. Maintenance of exhaust ventilation systems, and other types of protec tive equipment, should be a rule in industry rather than an exception. Too often the term "good housekeeping" has been interpreted as signifying only the periodic removal of dust collected cm floors, rafters, etc. Although such practice contributes to the general state of cleanliness of a workroom and should always be in force, the time has surely come when serious attention should be given to the installation and rigid maintenance of all types of dust control devices. In every plant there should be some responsible individual charged with the periodic inspection of all workrooms as to sanitation, ventilation, and maintenance of all dust removal and other protective devices. Perhaps the best criterion of the effectiveness of these devices is the periodic determination of the dust content of the air at the workers' breathing sane. Only by constant vigilance and an approach to the problem as outlined in this paper may one hope to make progress in the control of the dust hazard in industry. Often the benefits of even a most extensive program of dust control are not ismnediatety realized. This is especially true in dealing with fibrosis-producing dusts in plants where some of the workmen have already inhaled sufficient quantKies to L malt (pnlN . Public Health jaMh Bulletin No. a , ISOS. Iw w rd i S u l and atclalUe abnuiv H sttlag i t aa iyg., vol 15. no. 4, July, 1983. Philip, and Choate, Sarah P .: Control ot the silicoaii hazard fat laboratory ttady of the design of dust control system* for use `a. Jour. lad. Hire., voL 12, so. 3, March, 1930. S., aud F thnd, J. W .: Control of the silicosis hazard la luaatlgation of the K*Bey duat trap for use with pneumatic rack dMb i f the "Jech-hanuner" type: Jour. Ind. Hyg., vol 14, no. 2, February, 1982 Hatch, Theodore, W arns, H airy, and Kehey, George S.: Control of the silicosis hazard in the hard-rock iiidnetriea. lu . Design and opsrstton ol a dust-cootroi system far use with " in open excavation. Jour. lad. Hyg., voL 14, no. 7, September, 1932 Silicon and Silico-Tuberculosis ffcdfcal Problem s of an Im portant Industrial D isease B y ED G A R M A Y ER, M .D. New Y ork C ity A hidden dem ent of the cost of production is industrial disease. Industry has readied a stage beyond the concern only of wages and hours. Far more important is conservation jd t man power by preventive medicine and improved engineering. Disease preventive measures are not a cost, but, in- the long run, a great economic saving. Incidence. In the United States it has been computed that there are from SOQyOQQto a 1,000,000 people employed in occupations where a silicosis hazard exists. In New York City there are about 65,000 such employees. In a representative group of ptaaile workers in Massachusetts silicosis alone was present in about 15 per cent ana silicosis complicated with tuberculosis in almost 8 per cent Tuberculosis was the cause of death in over one-third of the granite workers which is four times the fruijd tn et for m ain of 20 years and over in this country. In foundry men studied in Massachusetts, silicosis was less frequent (about 9 per cent) and less advanced in than n granite workers. The duration of exposure in foundry workers w ith gm igimnoronionii has averaged many more years than that required to produce sHigggjg in an mdoatry such as gold mining. The tuberculosis hazard in foundries is nearly as great as that report! for some of the other dusty trades, but the figures are much lower than those of miners of gold, silver, copper and lead, among wnom the m ortality from tuberculosis is 8 to 18 times the general expectancy. Death rates for all naa-tubercukxis infections have been reported higher among workers than in die general population. It is suggested that the worker more often to acute pulmonary infections rather than surviving .1 IH* ... aa ' `'Ink or' at w m h i at the toeatiestf at 5 to toe s a i tob* < Mtocs to n .... -- to to* liflwtari toss*; .(*), ,, la 4faNMtor to toe atoetoflMMi; (3 ) f o V t o S j l iffity 7 f t T i 5 t o i t o l f 'to M to i** I w cqp l ti-- I bgr m se or I to t o iM at Sitka. Stoaifiraat aianxaSi of silica are ptaaort j a boriy ttoeice eoi torito, it te n toe body t o n # toe digestore tract awl toe toegi. Meet of toat taring toe stamads is ritototaird m toe atela bet a fritto tame enenet atomisd tato toe Mood as toown fey toe oooatato encretfaw of toca la toe orine. A l vegetable foods contata silicon especially toe hols of gratos, bay and straw. The low affici content of toe liver, to n apd lodton tottcatas toe little retention of toe ahatohed a ffia to toe body. Sflica content of toe arine of animal any be for the disposal of affi became of toe Ibw'lridney toreshhoid. Sities toe tongs to particulate fona is expectorated to part with its enveioptog cels, bat it of it is carried tote toe Many such particles the lyasph node* and even the spleen by way of the blood. The finest particles however, any be dissolved to alkaline bod;y fluids and carried away to solution, to be excreted to the urine. There may be a .constant drainage of silica from the long through the inhalation of extreawly fine particles of silica in dosty atmospheres, so small that they are not seen mader the microscope. A ttempts to influence toe absorption of silica from the lungs by administration of alkali have been inconclusive. Elimination of silica by way of toe sputum from patients having deposits of silica in their lungs appears to be higher than those having no history of exposure to d o st Only small amounts of silica are in the blood and this level is little different in normals than in silicotic*. Pathology. This disease is essentially a fibrosis of the lun^s developing espe cially in suds industries as hard-rock metal mining, granite cutting, metal grinding and sand-blasting. The pathological changes are believed to result from two causes, a blocking of the lung lymphatics by mononuclear cells laden with dust in addition to the action of colloidal silica, the exact nature of which is in doubt. The small particles under 10 micra are the only ones capable of penetrating the lung tissue. Although silica plays the dominant role in the production of silicosis, the ad mixture of other dusts tends to modify the pathological changes in the lungs so that these resemble then those of other forms of dust inhalation, and toe modification bears some relation to the percentage of free silica in toe mixture. Silicates, as in asbestos, produce a definite change in the lung, as well as other dusts such as marble, coal, etc. Such changes are represented by a fibrosis brought about because relatively insoluble minute particles of minerals in sufficient concentration have been brought by the activity of phagocytic cells into intimate contact with the pulmonary connective tissue. This fibrosis is a diffuse cellular one that occurs in the walls of the sailer bronchi and of all their finer divisions and extends to involve the supporting eonrgetive tissue of the adjacent blood vessels and to some extent also the walls of adjacent air spaces. However, when the great m ajority of the inhaled particles are composed of or contain silica, there develops, in addition, a specific and localized type of fibrosis called the silicotic nodule--an orderly whorled arrangement of cells and fibres, and with sharp definition from the adjacent paren chyma. Many dusts create a generalized fibrosis but only one, namely one combined with silicon dioxide produces die special fibrosis of silicosis. Sericite, known as white mica, which is a hydrated silicate of aluminum and potassium, has not produced in animal experiments the silicotic nodule, but instead generalized fibrosis resulted. Hosts must be differentiated into those which are chemically active and those which are inert when inhaled into the respiratory tract. Silica is a chemically active dust w hich m ust n ecessarily be soluble to a degree in the body fluids and its activity depends on its solability. This activity which is manifested in the areas where dust particles are carried along the lymph stream by phagocytes, causes lesions of two i; ]-:'.:| '5:r- II r ; Mbrio!_ft' aio_ anjvM jm mmktMo e s a ta n i from ta r t a o those ica are in the laot ia addition t The anali Ikosis, the ad ii th h n g s ao rap n n n n n n |n || Silicata, aa in duats ach aa t aboot became cetarathn have -- with the d iet occur in and extends to is and to some `eat m ajority of a, in addition, a orderly whorled adjacent parenly oese combined icite, known aa a s not produced costs resulted. Ktive and those hemically active i and to activity ireas where dust s tenons of two * _ th__ jBnita dllMtf' flMtaV taflfffij(Mr} IUCC n t^ k w ta A m is a w jalM y lower incidetice of '^ g M |b |'d ia i hi silicotic fames. 1 T | * certain A ^ . (fypnn a p i p t a r n m ' 'P ip e pnemnonoomdons may be onhr a . --,, Aetata, aa the atanmarr ftcoais of worfaara in dnitr trades Mobahly .re from the combined gpSJQB Bm Bgm -*--- nB E nQ ---:. n. -rf. . BL wRtaHHRf ' WB g n. _ ^ A. -- ---A H r a n B r a H H 1. ' n K In afioaaia 'it is not the mfctartd particles ***** a te bretUhed fat during life that r ecord dm ennae of disease, but the particles that have been dissolved Risk to work, efficiency and health may fas n ea tly accentuated through the inhalation of liochr divided particles even of a chcmscaUy inactive dust when m ere has occurred a lymph stash which h known to follow expoeure to silica. This lymphatic blockage h n is to retention and accumulation of the inert dust. In soft coal miners who gat what h called "m iner's asthma" we have this accumulation of carbon. Such patien ts are very liable to have a high inddeace of bronchitis with mechanical mid physical changes due to retention id anthracotk d u st Furtherm ore, unequivocal cases of silicosis, with o r without tuberculosis, can no longer be doubted Tuberculosis. Most apical tuberculosis is acquired before the age of 25 and so silicosis a t dm age of 30 makes a previous tuberculosis more serious. Most workers with tnbercoiosh going into dm mines before the age of 30 die of tuberculosis by the age of 45. Tim silicotic develops a sputum that contains tubercle bacilli late in life and dm children who are contacts with tubercular silicotics develop very litde clinical tuberculosis. It is impossible to say definitely that tuberculosis engrafts itself upon the silicotic or vice Versa, for we see apical tuberculosis in silicosis that spreads downward, while other silicotics show only the tuberculosis in the lower lobes. It has been found that most silicotics die of tuberculosis. The diagiMwi of silicosis is made prim arily on two findings, the proper history of occnpatinnal exposure to siliceous dost and the presence of abnormal shadows on the pulmonary X-ray. The physical examination and the patient's symptoms are of less value. There are other diagnostic aids such as the finding of large quantities of silica p n rtk k s in the sputum, quantitative determinations of silka in urine, and a t pent mortem, chemical analyses of the lung ash supplemented by petrographic examination, roentgen-ray spectrum analysis and special incinerating studies of lung tisane. W e must a t times rely on the pathologist to determine the amount and distribution of fiSrosis due to silica and from microscopic studies give an opinion on dm importance of this fibrosis as the ultimate cause of disease and death. Long fibrosis may be present without any silica. Silica may be present in lung tissue or the pulmonary lymph channels without associated fibrosis. Finely divided siliceous particles from lung tissue may contain innocuous silicate which cannot be distinguished from harmful silica particles. Hydrated silica which is not doubly refractive cannot be demonstrated with prisms. Therefore in the pathological section the presence of siliceous fibrosis can be suspected but cannot he specifically identified with the silkeous material that it may contain. Accordingly the microincineration method of Irwin with hydrochloric acid is now included in the microscopic examination of any lung as a means toward a surer diagnosis. Diagnostic difficulties in clinical medicine may be more obvious if we examine first the occupational history. Quartz grinders working under conditions of massive exposure may develop silicosis in acute form even in a period of months, whereas in other occupations it may take 25 years. W orkers in the same industry, indeed in the same room, experience different degrees of exposure dependent upon perhaps the dust-filtering capacity of the nose and functional condition of the lung as deter mined by constitutional characteristics and antecedent disease. The size and col loidal structure of the particles of silka, as well as the dosage and total amount of silica, will influence the rate of development of the disease. Apparently particles tin t are larger than 10 m kra are not phagocytosed in the lung. So a definite Ax to the X-vww. there are | essential types of ih sjw n f a tr iM , linear strands, smnfl discrete shadow. and homogeneous shadow of varying sises; these corre- spond to f a A rana nodules, and the conglomerate aauses d A re ria. The aoda lar shadows are iiiually characteristically around the M h n , o r coaglouMrate iwdidar shadows of bat-wine appearance extend into both ^ Iwag ie tds, o r nodator shadows n a y be dislrw atod w the o n e r two-thirds h s t fields, perhaps more pronounced on the right side, with the lower third kept dff by enipl iysensa. W ith isfr<iwB pt a n t , (he shadows are less sharp or the Nneer strands mte m wnret o r fuse. Large conglomerate shadows appearing oat from die hQ an leering die periphery oi die long d eer throughout because of emphysema The distribatKm of some of these lesion! may be determined by die postsaw assumed by the workers, and infection may likewise determine an ultimate atypical distribution. Many variations from these patterns are seen in die X-ray, especialiy under excessive exposure or when other dusts are inhaled, or in die pr esence of infection. It is probable that die main source of the diagnostic diffi culties is earned by the emphysema which muffics the physical signs and is respon- with emphysema, such as restriction of costal and diaphragmatic movement, dhninu- sible in great part for die absence of symptoms. It may blot out, even on X-ray, die silicotic lesions of fine size. Examples of such difficulties in diagnosis as encoun tered by us are the following: Case / --Mr. T. A forty-live year old man entered the New York hospital complaining of mild cough and expectoration of four months' duration. He appeared acutely ill, his fever was 103 degrees and respiration 2& Rales were elicited over the upper half of both sides oi the chest. Examination of his eye grounds revealed bilateral retinal tubercles: his sputum contained numerous acid-fast organisms. The X-ray revealed fine mottled shadows distributed throughout both lung fields and a small cavity at the left apex. A diagnosis of miliary tuberculosis was made. However, after one weeks' stay in the hospital, his temperature and pulse returned to normal and during die following month he gained 18 pounds. The signs in his chest now became confined to the left apex. In view of his_ unusual progress the diagnosis of miliary tuberculosis was doubted. H is occupational history revealed that up until three years before entrance to the hospital he had worked for 20 yean polishing leather on a sandpaper wheel. There were numerous machines in the work room and no precautions were observed to clear the very dusty air. His sputum was examined dirough 'the kindness of Dr. Burke of Raybrook, N. Y. who found H laden with numerous doubly refractile silica particles. H e expressed the opinion that this was consistent with silicosis for he had found such numerous particles only in cases of silicosis. The patient subsequently died of a tuberculous Retinal tubercles were demonstrated on microscopic section. The pathologist's report was miliary tuberculosis. Ashing of the lung showed increased s3ica content, consistent with undue exposure to dust (more than 2 mgm. silica per gram dried tissue). Case If--Mr. R., aged 54, entered the New York hospital complaining of hemoptyses. dyspnea and chest pain. On physical examination there were rales and dullness over the upper third of the right chest anteriorly. H e ran a low grade fever but was robust and felt quite well. The chest X-ray disclosed enlarged hBum shadows, particularly on die right, and diffuse mottled discrete shadows  * *:'iS * IS: ..'"Mil X -ray, 1M K 8 d over eveetod rg g li jtiNi* * ` i ,l!'itif,i a^ll lllfflt! W0 131 m hm cutter u 4 llgra>. alone or aa associated igaentiy removed and tiife does not ew dain the whole ifo alii alive and certainly, frost the X-ray standpoint, we cannot spy r, aged 4 6 entered Bdlevne hoqtftal bccapae w A dvspoea. There was some dullness and Chest X -ray rnevealed a homogeneous shadow no tabercte bacilli and IWodot study - - - - -- ---------- ---------- -- - -- aminatinn disclosed a bleeding mass in n p t nmin bronchia. Symptoms t a i disease progressed (bring (he fotknving four yoara. Discrete mottled Shadows first aoncamd fit the imncr rixht lone find and the Shadow a t the right base cleared somewhat Three years later extensive ab normal shadows were prescat thronphowt both long fields, particularly on the rig h t of chr onic p tatanotria of unknown etiology was made. A t no tune was of silicosis entertained, because as for as could be determined he had of exposure. Furthermore if there wore silicosis it behaved very having the tenon confined practically to the right base at the beginning to tire left lung. Autopsy however, revealed a typical silicosis with a small degree erf tuberculosis. A picture of the lung showed how much more extensive the silicotic process was in die right lung. There was stenosis of die right middle lobe broochus with bronchiectasis in this lobe. Chronic infection in die long field probably accounted for the unusual localization. This case illustrates how necessary it is to have the history of dust exposure for without it here we are unable to even suggest a diagnosia C u r IV --Mr. C., aged 45, complained of cough and dyspnea with slight expec toration and gave a history of having worked for many years repairing tires, using talc powder. I t was difficult to obtain accurate details as to the possibility of silica exposure except that the rooms were filled with clouds of dust. Rales were present at both aptces and a few tubercle bacilli were found in the sputum. Discrete and stringy shadows were disseminated throughout both lung fields. We know from the positive sputum that tuberculosis is present. The patient has, however, been well for a period of two years. The doubtful history of exposure together with the numerous discrete nodular shadows in his lung, which are con sistent with silicosis, makes this patient a problem. Is this tuberculosis alone or is this tuberculosis with silicosis? The patient is still living a year later and working. Crmctusum. Cases such as these are exceptional, but their existence must always be borne in m ind If occupational history is inadequate and X-ray, clinical and laboratory studies prove misleading, the diagnosis may present great difficulty. However, a comprehensive study of all possible data usually clears up the problem with reasonable certainty. AD JO U RN M EN T l The Bka per m ag of re rates i a low enlarged shadows 412 Tmnty ftmrk d mmnd StfttyCongm N*o* S*f*tyCotmc* D ust Hazards in the Quarry Industry . By J. WM. FSHMKL O m tim , Iadostrfol Hygkn* Laboratory MatrapoHtan L ift Inauranco CtL, Mow York Q n rn in f is a special type of mfoinf, the method* of Vorkuta are the same m some m tm w While baw ds in quarrying and mining bam been recognised and Stamfords of operation adopted for their elimination, n e health hazards ham not received great notice. This is probably dne to their slow progress in producing disability or death. The oldest published data on the harmfulness of exposure to dust deals with the mining industry. Some of die records date back before Christ, and as early as 1556 Agrkota*, according to Mavrogordato*, in his De Re Metallica, described the perilous occupation of miners dne to inhalation of dust and pointed out that permanent injury to die lungs resulted from exposure to certain kinds of dust, but not to ail kinds. In 1780 Ackerman*, quoted by Koelsch, described miners phthisis as the most "frequent and specific" mine wotkers' disease and said that physicians did not agree regarding the true definition of i t The first investigation of health hazards in the mining industry in the United States was made in 1914-15 by the United States Bureau of Mines in cooperation with the U. S. Public Health Service in the Joplin, Mo. mining d istrict Of 93 men examined, 64 showed definite evidence of pulmonary disease, 3 were suffering from non-pulmonary disease, and 26 were seemingly well. A further examination of 720 miners made from May 15 to December 31, 1915 showed that 45.7 per cent had silicosis and tuberculosis and 5.3 per cent had tuberculosis. A report in 1917* on this study by Lanza and Childs contained the first detailed X-ray studies of silicosis made in the United States. The operations in this district are principally in shallow mines. A recent study by the United States Public Health Service* of the exposure to dust in coal mining showed that 2 per cent of anthracite miners and their helpers, with less than five years exposure, showed signs of pneumoniconiosis and that the rate increased to 16 per cent among those with more than fifteen years exposure. These are records for persons tinder 45 years of age. Kibbey* reported in 1931 that practically all miners working in the bituminous coal mines of his company in Alabama had anthracosis demonstrated by X-ray and there was a high m ortality rate from tuberculosis among them. Kibbey does not associate the tuberculosis to inhaled coal dust but rather to a retarded calcium metabolism due to deprivation of sunlight. The Industrial Health section of the Metropolitan Life Insurance Company, in cooperation with the Department of Industrial Hygiene of the College of Physicians and Surgeons of Columbia University and the New York Tuberculosis and Health Association, undertook during 1928 a study* of the rock dusts to which are exposed rock drillers and other hard rock workers engaged in excavation and subway con struction in the Borough of Manhattan. New York City. Forty-two per cent showed *Agrcola, Georgia*, De Re Metallica: Book I. Tran*, from first Latin ed. of I5S6 by Herbert Clark Hoover and Lou Henry Hoover. 1912, p . 6. * Mavrogordato. M.. The Etiology of Silicosis. Kept. 4th Meeting ol Permanent Internal Commission for the Study of Occupational Diseases, Lyon, April 3-6, 1929, pp. t-22. * Koelsch, Frans. Theophrastus von Hohenheim, called Paracelsus. Of the Miners' Consump tion and Other Miners' Diseases. Deut. Gesetl. Gewerbehyg., N, F. 12. 1925, 69 pp. * Lansa, A. L. and Higgins, Edwin, Pulmonary Disease Among Miners ol the Joplin District, Mo. and Its Relation to Rock Dust in the Mines. Technical Paper 106. Bureau of Mines, 1915. Lanza. A. J. and Childs, Samuel B. Miners* Consumption: A Study of the Disease Among 71nc Miners in Southwestern Missouri, V. S. Public Health Bulletin 185, 1917. *V. S. Public Health Service. Treasury Dept.. Public Health Bulletin fX t, The Health of Workers in the Dusty Trades. HI. Exposure to Dust in Coal Mining, 1933, pp. 7-19. TKibbey, C H.. Relative Pneumonia Fatality Among Surface Workers and Miners, American Journal of Public Health, Vol. 22, No. 4, 1932. pp. 360-366. 'S m ith, Adelaide Rm o and Fehnel, T Wm.. Silicosis Among Rock Drillers, Blasters, and Excavators in New York City, Journal of Industrial Hygiene, VoL XI, No. 2, Feb. 1929. 413 SI il 4 iiW *iiiiw ol 201 IMII VmivV Mb wKDvff 1of Aim others trig h t laatlO M, aix of Web ere ._ -- --------- k subwsy cow tn iettoB work. The build- i M c io c M w Ml m v rr opentioa* b r u general methods bo h id ir ** TM* *rai * " l0,'e PWI"IW^ * 4mt *** M t concentration n g r iR P * <*. hy iocbhmmmxcrr odrntiuiamg varmieda mfromm mS3 nmuiillhionp to 1177J3> bouaiufoeon . leoe thon M m ienas int greatest dmmeter. per cnMc foot of air, m i the Mica of the rock ran from#vgh pAMerI crac' Atom twtri MpAeAr cent* tn ifiny iananAaiiMwAArAii B n ! vtDQr vDBMDOkOma than drilling were r i noted to fcigfr dmt cou* M j w a M fanerai a ir ample taken rimer from 16 to t motion u t partide per eanie foot of air. la subway tunnel work general air cooditioos ranged from 2 to 37 million, murkmg from 4 to 270 minkm and water Leyners drifling at heading from 136 mfllion to 2 bilBon. The teats on wet drilling were made at two diffrait locations and ere taken addle 5 wet drille a rm operating. So far we hare only mentioned dost concentration and free silica, to it is intereating to note die comparison of particle sizes found with dry and wet drilling. In the one tunnel d im waa little seepage of water, so that the workings a rm dry and the particles of dost generated by wet drilling showed 96 per cent less than 10 microns in sise, 75 per cent less than 5 microns and 50 per cent less than 3 microns. In the other tunnel there was an excess seepage, necessitating the wearing of boots and the constant operation of pumps. H ere the d u t generated at die beading by the same number of wet drills snowed 99 per cent less than 10 microns, 98 per cent less than 5 microns and 50 per cent less and 1.7 microns. In comparison, the partide sites found in the dust generated by dry drilling with a jackhamer showed 95 per cent le u than 10 microns, 65 per cent le u than 5 microns and 50 per cent le u th t1* 4 nacrons. Later tests substantiated the conclusions that wet drilling did not allay the extremely fine dust hut did substantially lower the total count In a test conducted in October, 1931 in a tunnel in die Bronx, New York City, seven CPS type axial water feed drifters were mounted on two benches at the heading with five on the upper and two on die lower bench. A water pressure of 75 pounds was maintained and the drilling rate was 100 feet per drill in five hours. The d u t concentration averaged 473 million particles per cubic foot over a 30-minute period of sampling. In a study of underground iron ore mining comparisons were made of wet and dry methods of drilling and it was found that the rMUCtkm of dust was ten to one. W hile this appears to be a long step toward the solution of the d u t problem in drilling, nevertheless when we consider that concentration as high as 5 and 6 billion particles were found, reduction to one-tenth of this concentration by wet drilling u not sufficient, especially when a considerable amount of free silica is present The M inistry of Health of the Welsh Board of Health published a report* on an Investigation Into the Alleged High M ortality Kate from Tuberculosis of the Respiratory System among Slate Quarrymen and Slate W orkers in the Gwyrfar Rural D istrict, in which a thorough investigation of working conditions in the quarries and cutting sheds was made and living conditions noted. Physical and X -ray examinations were made and the incidence of tuberculosis and mortality statistics compared for various types of occupations. Unfortunately, no determina tions of d u t concentrations of die atmospheres to which the workmen were exposed was made, nor were determinations of the chemical or petrographical composition of these dusts made. It was noted that the m ortality curve for tuberculosis reached its maximum a t a late age and it was concluded that : 1. The workers in the slate sheds are exposed to an injurious d u t. 2. The dust concentrations are not very great and the workers and quarry managers, together with the local medical men, do not consider the inhalation of the slate dust to be injurious. H. IL Stationery Office, London. 1927, M inistry of Health, Welsh Board of Health, I q n ttl on Public Health awl Medical SobjecU No. 38. ' ' --ndkla-- M t nat wialariM# fac the high 'dalfc --8 in a i dAa*1* S ? ? te ra S M L ^ S e ^ a T S i!^ to T n rA e tetriet of Ver- iM t aiade many co n --all a of mininf yim tioa, under work and also oaecvariM -- with pen art or ty p M r narryi* opM m hove fa--4 ft*> g--eral --atSatioa plays a very import--I part ia tte W b ----ee* iv e lo a n d ^ tt dust concentrations as hiah as 6 biOlon particles par eM Udontwere commonly encountered ia drifting underground and we encountsrad ia cciuporuon the following dost conditions ia p a rry work: T yped Kadc Quorry Operations Tfca tf r g D--t Concentrations ,...................... Cement rock...................... Asbestos........................... "W ........................... Jaddsam er................................ 29J million particles, leu tium 10 microns, per co. foot " (wagon type drill). 23.4 * " " (2U (3SA "14 M id M C594^J<S4 Mucking operations in general show low dust concentrations, approximating the general air dustiness of the locality. Conditions are, of course, modified by air cur* rents so that while the shoveling operations may not produce a heavy dust concen tration, drilling operations dose by may set up dust tin t grossly pollutes the breathing aone of workers engaged in mucking. Normally the dost concentrations in quarry operations are dependent upon the worker. In few instances is the worker required to remain exposed to a heavy dust concentration, and then only for a short period of time. It is usually possible for him to work in a position away from the direction of the air currents carrying the dust clouds. This is especially true where the drill is of the mounted type. In case of hand jackhamer drilling, the operator is required to bear down with his full weight in order to supply the required feed to the drill. Here toe rate of drilling more or less dependent on the physical characteristics of the man and often tiie contractor picks only the heavier men for this work. W ith mounted drills, tiie weight applied or the feed is constant and toe rate of drilling is not only more regularly progressive but also the operator is not required to be constantly exposed to tiie arising dust cloud. Tests on mucking show that the dust generated is dependent upon: 1. the fine ness of toe m aterial; 2. the dryness of toe m aterial; 3. the rate and method of handling. In recent studies in the iron mines in upper Michigan with mechanical scraping of relatively wet material, the dust in the breathing zone of toe tugger operator closely approximated the general air of the mine area. In quarry and building foundation work the same conditions held, but in most instances the dust concen trations of the general air were too high for safe breathing over a period of time. A test run recently*1 of hand shoveling in a dry mine indicated that greater dust concentrations were generated when the material was thrown from the shovel into toe car. Samples taken with two men shoveling showed an average dust con centration of 83 million particles, but on applying suction to the top end of the car to entrap and remove tiie arising dust, the dust concentration was reduced to 8 million particles. Crushing operations are usually associated with quarry operations. These oper ations, together with screening or sizing of materials, are usually done on the dry material. Usually tiie crushing and screening plants are mechanical, requiring only "X asers, Eidward SiKcoiii or Pnenmoconioeis in Vermont Granite Cutters and Slat* Worker. T it New Aim _S~__P___&_ itiotnutme aoiiMMueduincignea, nAdeMf. c4U, l1ia9r1x2,icVolotE. n2g07in, epepr. ,2T03o-2d0m. kal Publication No. HO, Cootrol o4 Dm * ia t : 1- a Ha a odtjr ie fine* hod of pentor adding concen>i time, greeter AMf. (he dry a g only Hoe Ne ^ rs;,t f ^^ n J(ji 4ij m 'f -V1' ' iuiM IP wi wWffiBMfii rM^V' wHOTHHNE^Mm '^T -^ ....... . . . , . n ................. r,,. .............................................. , aafc a m i vnwtice. with m coven over dbg i cwwi ' ^ J b a survey of e sffka grinding phot, he Mlqwin* d irt concentratioos were , __ ,, .. L o o tm dk M p l h i Wigging room ......... TotolC oonttoM fflioasoi 'fc riid ^ liM -ljw l|g jta w % pgf eg, ft. i t r i t t f M *25 9J2 ........................... .................... 69.33 Them tem w en taken in the aammer and there was good general ventilation with a l dean and window* open. The u n t o and grinding room operation* w en HlwiM^HHBRBwp WQVUnHK y * SHBRIOIl OK wBm OWE* ' UHw^wBwRBIlHVf DDK KBU I foOBi dm two men vt me two w n u n dmcddm ihb two men tn itiw t toe silica into a car for shipment. These four men were exposed to the highest concentration in (he whole plant. A sim ilar study of * feldspar mill operating with open vibrator screens showed the following concentrations: Total Count in Millions of Particles, less than 10microns. Location of Sampling per co. ft. a ir sampled A t roughing ro ll......................................................... . 2/556 At roll crusher.............................................................. 1,589 A t screens (feederen d )....................................................... 4,652 A t screens (take>offend).....................................................8,885 Sample* taken in a wet limestone screening plant showed 0.91 million particles as the general air dustiness. This limestone was burned to make caustic lime and samples taken a t the kilns showed: Charging floor................................... .......................... 2.5 million particles Bottom of kilns....................................................... . 1.7 " " (discharge of itiins) Summing up, our experience gained over a number of years by making surveys of varied industries, we have definitely concluded that: 1. Dust is principally produced by mechanical operations and in the mining and quarrying industries, drilling operations are the chief .dust producers. 2. Employees at other operations than drilling are often exposed to a high dust concentration due to pollution by dust generated by the drills. It is, therefore, logical to conclude that the prop- way to eliminate dust is to entrap and remove it a t its source. While wet drilling may, in certain instances, he effective, the use of water offers other difficulties, especially in freezing weather. The effectiveness of the Kelley Trap has been demonstrated experimentally and its adaption to drilling operations in its first commercial use on the foundation of the Metropolitan Life Insurance Company's Home Office Building at 24th Street and 4th Avenue, New York City" was successful. A series of later tests conducted in the Balmat mine of the St. Joseph Lead Company" showed the practicability and efficiency of the Kelley system under severe mining conditions. The dust health hazards of the quarry industry are such that they can readily be eliminated by efficient and economical measures. * Hatch, Theodor, Kelley, George S., Fehnd, J. Win., Control of the Silicosis H ta r i in the Haid Koch Iadastries, II. An Investitatioo o f the Kelley Dust Trap for Use with Pneu matic Bodt IhriBs at the Jackhamer" Type, Journal of Industrial Hycieoe, Feb. 1912. tell *\ ../kH `i?8 . ' '-;V fa te brief fa sort of V Lg. M W T i W - _.*----- of its GROUP U -U tr Moat of die coiupommIs fajM s group w of M b mineral powder type of o partkgbr tbo ten thi n 200 nceh end oMiy of then 1cm Am 200 Mash or w w finer. Very few of them wwti le herd or ttn in e purtfafae w h es sfiicn, coruufisM^ etc. Lfaewfae only e very few or toidc, eo oo the whole this group b comparatively free from heehh hevsrds. However, they mo ill more or 1cm deity when handled core* body --d there fa always the ***--*y deed board present. Good storage bfas^ con veyors, hooded mffls, and efficient txhsust h n can readily diminste i0 doit hsserds raid in moot cues also prevent harm from the toxic or 'silica-bearing compowsfa, There are several compounds whom handling should receive special consideration, snch for instance u lead or silica bearing compounds. These are so designated in the following conspectus of materials in m is group. A hmmum Flake. A fine cream colored powder consisting primarily of aluminum silicate. Used u a filled in rubber. I t fa non-gritty and nan-toxic. Ammonium Carbonate. A white crystaline or lumpy powder having a strong, pungent odor of ammonia. Readily decomposes and gives off irritating odor during mixing. Used in sponge rubbers. Slightly toxic bat very little hazard in connection with its handling. Antimony Sulphidet. There are two types, the golden and the red antimony sul phides. They are used for coloring rubber articles. Some grades contain a con siderable percentage of free sulphur and calcium, sulphate. They are slightly toxic ami also are irritating to skin and mucous membrane. No hazard with careful-' handling. Asbestine. A fibrous variety of talc used in rubber as a filler, especially in packings and gaskets. Is a magnesium silicate. In appearance, it is a white powder, non-gritty and non-toxic. It should be borne in mind that many of these silicates, when not pure, may contain traces of silica. No hazard if dust is kept down. Asbestos. A fibrous magnesium silicate used in many types of rubber goods, especially of the packing and gasket type, and where the rubber must withstand considerable heat. It may be obtained in many different lengths of fiber, varying from an inch long down to almost a powder. Grayish white usually, in appearance. There is no hazard connected with handling this material in compounding. Barium Dust. A trade name for barium sulphate (which see). Barium Sulphate. A heavy white powder used for reinforcing rubber and also as a filler. Insoluble m most solvents. It is non-absorhable and non-toxic. No hazard in handling. Barvtes. Commercial name for natural deposit of barium sulphate. Beckton White. A trade name for lithopone. Blanc Fixe. A trade name for barium sulphate. Blue Lead. A grayish-blue powder used as a mffd accelerator and for com pounding. A mixture of active lead compounds and very toxic. (See lead com pounds.) CiarfmMH* Yellow. A fine light yellow powder of cadmium sulphide, used for coloring rubber. Slightly toxic. It era cause irritation of mucous membranes rad also gastritis. N o hazard with careful handling to keep hands clean and dust down. Calcined Magnesia. (See magnesium oxide.) ml *<. efaUyJn and also k . No far lead cm * osed for raaes and bat down. ______ ^.wnnc m o * m ' mr n*mJ *n * # 9 * * * * * * * * m * fac B**3r WpSSmmm WW WBRHHBI Qh " C ly v n i Y tlh m A Aha 3rtBow poMidhr hmhI for coloring rubber. TUs is o CbnQMMbB s i bMfcd^ dlbQUfljb QI0H TC dpO AMMHHSHI oi .doc Stti bCfllMtt* Bvk Ah lead It is the one asuaSy wed far nM er. Whfle die chromate is sdatirdly iasol- w t and inert, It is always wise to h H l t lead compounds with extreme care, due to wm pfwtfic ot ftry ic tift n h mhiihimi wntcii iuhem m present (swt mm ) C bm . There are an imwroerabie number of different kinds of clays ranging in mfs from white to Mack. The ones used for rubber compounding are nsoaily the white variety ranging fa color from exceedingly white to cream or buff. Most of toe day* a n very fine smooth powders varying greatly in both their chemical ` cal properties. They ore of natural origin and chemically a hydrous wBiawhe. The days are usually non-gritty and are non-toxic. They are fillers and fa r reinforcing. Criaum Antim m y. Another name for red antimony sulphide. ,* --J i s--fowarvon Earth. A very soft earthy rock composed of the silirious skeletons Of M B plants called diatoms. It grinds to an impalpable powder and is _ _ and fluffy. It is w ed for filler in rubber compounds. It is non- bnt care should be taken to keep down excessive d ust S au ry. A fine abrasive powder used with rubber for making erasers aad 'wheels. Basically it is an aluminum oxide. It is non-toxic bat very sharp and to inhale. Take same precautions as for silica. Also called corundum. f a t * floar. (See diatomaceous earth.) Prtnck Chalk. (See tale.) PalUr't Earth. A d ay relatively high in magnesia. Used as a filler in rubber goods. N on-gritty aad non-toxic. (A lso see days.) Gold* Amtimeny. (See antimony sulphides.) Graphite. A grayish-blade soft greasy powder. Used for lubricating rubber moulds and as a filling material for such compounds as gaskets, packings, etc. It is an impure form of native carbon. It is non-toxic. C row d Giass. A very fine powdered glass used for compounding rubber to make erasers and other rubber abrasive utensils. It is very sharp and same precautions should be observed as for silica. I t is harsh on the hands but non-toxic. (Tjrftnw A grayish-white powder used far compounding rubber. It consists of a pul ren acd natural hydrous calcium sulphate. I t is non-gritty and non-toxic. Hard Rabbtr Dart. A very fine ground hard rubber, grayish to black in color. I t is very light and fluffy and sticks to whatever it touches. Ordinarily it consists mostly of vulcanised hard rubber which is rubber and sulphur but may also contain odser mineral o r organic substances used in compounding rubber. Dust should be Iwpt down, bat otherwise the m aterial is not hamsdous or toxic. P^fip?Rj4!'W [*>t ; ,!' . ;# || :S i , 4 H T mn t y - f m H tt4 4 u m u tS t f ^ C iH tfi* u y i iiirf S & * 9 r i l i t i V'! rife (Sat i Jfinan Ottfife (See land eenmndK.) of fora. (See rad indde.) rar& .) (See dm .) (See to rd k ) The tight - - T r i l l ---------- - (See oxide.) le ultra spoken of ae Hghe A Mack eeehixi pigment sbmined by burning oOa and,offer * Its chanKtortotfcs a simibr to car- too Mack, (Web U a i Ci !) It to not BIB^Ba w w U j ___ j - t . to any gnat extent It is not texk. BK Os OfBMO BSBHBnBOnb BB NBB BBB^ 7 mS Some of these rsf^ssstfteiSS C d*ie m MVI need i hi nAher bod oxide or The nsnal b ad compounds need b ad are no b u f tr used to any extent These are active of lend which reacted readily wife sutphur at p vnksniratkiw They are xmra or bse active compounds and readily TiBHi BHO mo system tw w r iumwqii o itiiia iB o r uirougn iooa gob* by contact with dbty hands or clothing. VjlacAm^ o w n 2ias bsAis21ii ^qbAnAq^ ato-- ao oonsMSfiBW fiw B mch X^a AbB sA As As^iBi aa o o A A AnS BrAaa sl on r to n tof t A ri wetrodstf swd Bs^oSds4 footjfa^ I t vw a jyood ood ^t^sBixtcv fctoooi io ocirtteiB twv^Bg ^cs ws ov wf ^ w a e w i Ia wt insn mv ii anmcAtSiYvWe* bn^wrai^sroe^bra i s f nne^ws ie hw oe a^ kw li bw ew twwe eswteends . v k h ^w^w^w cbAmb b w * Ia wt ias anns^mo^wfwt.g waxy ^^AS^B^B w uw isiC i s--o-- mA ueBrBe it s-- nA Ao s a a i r ^^ABB^^AA Bo^kW o wU l^Ba mB BeB il wA b B o^ B aA mB ^^ar^Bi^h^Bih^^kB ok sHcaaAm^. m nanas ano ciqkbbwp* * can oc hobwcb wbbi porm x sasety n ejeammesa is floaemanL Lead oxide or litharge to probably the most extensively nsed lend compotmd A anAa^ a te OSba o^B oA e toA^. ae^ba asosJtbiAcA suBrAeoLAab kaisA a neavy Sb^MBBBBB dEsBAnBB aB eUoBeBaaSwb e^^a tb o^^^o^a roow vOKoeea yoaroer* WfoL eb o ast ats bv^eBrHyB noe ^^^BA am B B tfS al l AetMnAa aB cB aB v^ UarByf bk jbArBvMt zA rBaB BvbnSyb , Bs^smhl ^wB a^ iaa^c^aLiyI b ^inS o. * w* - handling this m aterial should wear a dnet mask n m ere to l b slightest k m e r of inhaling any dost o r getting it in the month o r saliva. It to dangerous to handle tobacco, com, fruit o r any food until after a thorough dean-up. Mixing nulls should be hooded end every precaution taken to beep down d u st Lead oxide is e very active m ateriel and consequently very toxic. There to no need to enlarge on Lead Poisoning as the subject has been very thoroughly covered end I am sure all rubber factory safely heads are fam iliar with the symptoms and treatment of lead poisoning cases. Litharge can be safely handled if reasonable care is exercised in its use. The worker dtould be instructed as to its serious toxic properties and pains taken to instru ct him how to safely handle i t Stdtlimed white lead is largely bad sulphate with about 15 per cent of active lead oxide present It is the free lead oxide which is the active accelerating ingredi ent and also die real toxic substance. W hile much less toxic than die litharge, it shook!, however, be handled with die same care as the latter substance. B u b white lead is a white powder consisting of a bask carbonate of lead. It is not now nsed to any great extent for rubber compounding. But it is a very active and toxic substance and should be handled with as much care as litharge where used. Anyone using die above lead compounds to any extent should post themselves on the symptoms of bad poisoning, its treatm ent and avoidance of trouble from poisoning. Lime. A fine dry white powder used quite extensively in rubber compounding as a secondary accelerato r and drying ingredient This, compound is the so-called hydrated calcium oxide o r slaked Ihne. It is slightly caustic and irritating to mucuous mem branes but non-toxic. No hazard is involved in its use. Litharge. Lead oxide. (See lead compounds.) Litkopone. A very fine white powder consisting of barium sulphate and sine of high coloring powder. I t b one of the most widely used pigments for yrmtwring white rubber goods. Being rather in e rt there is no hazard connected with its use other than foe general dust hazard. The zinc present in the material might be dbsolved if m sidrrahfo qnantilbs of dust were taken into die system, but zinc in aach grantitin wmdd not be considered as a ta s k material. ,*?t ' .... M b.) factory * ct taken to id. I t b *y active ere a d elves on boning. xfing asa in ju n m 44S : IjJ jJ Hi M It b tan tarni I * o n tita r in d ite * . u n i m fcd h-- v wirfBed w ^ e i b a id the .other tight I t bw m * a w and n taasto darhar la 'i f f i i l S ' '"Sw ml 1B S t b *rih2^TR ltatiM r IB i ' dStiTST ''and! 1b bmmI ric. No hasard Xbeg ' flam e * mmmesinm dda. k m f t a M ia a m sifciiteiititid i wbca grooad fine is a soft glittering T he fB ftk k a ara l a t h:dmpe aad tiida over each other giving the slippery 1b g ra tifie . H a color *bbb flnMh a cream fahe to gray, bat the M i 1er n i t e r i t fabjy food kite. I t b need for dm tfeg raw to h a p the d a te b a n etichiag tog ither and abo for daetiog finishing geode, _ _ t o rive a -- t gtirtrning and gloNinc firith , b ale Md hi padtiags and mechanical good* as a fitter where goods are to resist heat and add. The material b nan-toxic and there is no hasard other than the dnat h e a rd . Cheap grade* m b it contain traces of silica. Oxide o f M ognetk. (See magnesium oxide.) Oxide of from. (See red oxide.) P o n t While. (See whiting.) Plotter of P ont. (Seee gypsum.) Plumbago- (See graphite.) Pumice. A grayish powder consisting of ground leva. It is a complex silicate of alummom, potassium and sodium. I t it used as a soft abrasive for producing a smooth, polished surface on rubber goods such as mechanicals and rolls. Also it is nsed as a file r in ad d and heat-resisting rubber goods. I t is non-toxic but reasonable care should be exercised in keeping down d o st P n u tim Blue. There are a number of so-called Prussian blues with varying shades and solubilities, all belonging to the iron blues. They are fero-feri-cyanide compositions. The bines used for rubber are the insoluble type and prepared to withstand the temperatures of vulcanization. They are used in comparatively small quantities and there is no hazard connected with their handling. Red Oxide. A fine red pigment very dense and heavy, and consisting of the red oxide of iron. It is also called iron red. It is one of the most widely used red pigments for coloring rubber. It is non-toxic and no danger involved in its handling. Advisable to keep A n t down as it flies readily. Red Ochre. A Adi brownish red powder used for coloring rubber goods. It does not give the brilliancy of red oxide. It consists of a ground natural impure form of iron oxide. It b more gritty as a rule than the regular red oxide and often contains silica. It b non-toxic, but care should be exercised in keeping down dust Ate to possibility of silica being present Rotten Stone. {Sat tripoli.) Sooi. (See silicon dioxide.) SiReo. (See stiioon dioxide.) fifteen Dioxide. Also called silica and quartz, sand, etc. A very hard abrasive powder varying in particle size from a very fine powder to large, sharp particles which we know as sand. The color may vary from almost pure white to yellow or brown or grayish. This b the material which has been so widely discussed in cases of I t occurs as mi im parity in many dusts and powders and is usually pr esent in m m y road d o st In rubber compounding, its use is confined to such special rubber articles as erasers and abrasive wheels. A very fine grade is also used as a sp trb l file r for certain rubber goods. However, its use b not general throughout SdfMy Section, A A R--St*mm Rmlrood Section, N S C Railroad Section, NSC Officers 1934-1935 General Chairman T . H . Cauow , Pennsylvania Railroad, Philadelphia. F irst V ie* C lw n w i--W . H . F ailing, Central Railroad Company of New Jersey Bending Company, Philadelphia. Second Vice Chair men--C. F. Laksox, Missouri Pacific Lines, St. Louis. Members of the Committee of Direction: Eostern Territory..H . R- Cole, E rie Railroad, Cleveland, O hio; Chaxus E . H ill, New York Central Unes, New York City. Western Territory--L. F. Shedd, Chicago, Rock Island and Pacific Railway, Chicago. Southern Territory--D. H . Beatty, Southern Railway, Washington, D. C. Secretory--J. C. Cavtston, Association of American Railroads, New York City. Officers Elected for 1935-1936 General Chairman--C. F . Lab son, Missouri Pacific Lines, St. Louis, Mo. First Vice Chairman--E. A. Mere*, Chicago, Milwaukee, St. Paul and Pacific Railroad, Chicago. Second Vice Chairman--E. G. E vans, Louisville and Nashville Railroad, Louisville. Members of Committee of Direction: Eastern Territory--A. O. Beck, Canadian National Railways, Montreal; H. A. Rowe, Lackawanna and Western Railroad, New York City. Western Territory--F. W. C uirris, Denver and Rio Grande Western Railroad, Denver. Southern Territory--L. G. Bentley, Chesapeake and Ohio Railway, Richmond, Va. Secretory--J. C. Caviston, Association of American Railroads, New York City. A complete report of these sessions is published by the American Railway Associ ation in a booklet entitled, "Proceedings o f the Fifteenth Annual Meeting of the Safety Section, Louisville, K y., Oct. 15 to 17, 1935." Copies of the booklet are available from the Association o f American Railroads, N . Y. C. The follotving is a condensed record. TU ESD A Y M ORNING SESSIO N October 15, 1935 The opening session of the Safety Section, Association of American Railroads-- Steam Railroad Section. National Safety Council, was called to order by General Chairman T . H . Carrow, Supt. of Safety, Pennsylvania Railroad, who presided. 459