Document DGOmaxDv4164mzZzDQg76E32Q
1935
TRANSACTIONS
National Safety Council
Incorporated
TWENTY-FOURTH ANNUAL SAFETY CONGRESS
Louisville, Kentucky October 14 to October 18, 1935 The Brown, Kentucky and^Seelbach Hotels
Copyright, 1936, National Safety Council, Inc.
Ticcnly-faitrlh Annual Safety Congress--National Safety Council
. Carney, Chicago Safety Council,
i nr I. Cati.in, Aetna Casualty .V Surety Company.
t'i'iie, Evanston Safety Council.
I!. ('oi.f.man, Cement Section.
Ili.iuintT Cot:sox, Safety Dept., Nashville Chamher o! Commerce.
NK Kmekv (.ox, Berkeley Traffic Safety CnnmKsiou.
Cm. nt'.v, Relhleheni Steel Company.
XV. Dami, Metals Section.
iiiam Ci. Dkanlu. Rochester Safety Council.
us A. DkBlois, Consulting Engineer.
E. Drc ckr, Mason City Safety Council.
XXL Di.Mir.sv, Rood Section.
M. Dirt/, Rubber Section.
trs I!. Douglas, The Philadelphia Gas Works Co.
. I.oris I. Duni.tx. Metropolitan Life Insurance Co.
D. Fennell, Consulting Engineer.
y un A. Finkbf.inib, Toledo Safety Council.
. 11 amt F. Fishf.r. Chicago Rapid Transit Co.
XX'. F kk, Jr., Marine Section.
.
ms. Fr mntAi.t), Western Pennsylvania Safely Council.
ward I,.- Fonua, Burroughs, Wellcome & Co. (U. S. A.), Inc.
I*. Foih.jix, Lehigh Valley Safety Council.
Fosrru, Jr., Quarry Section,
nx B. Gmsox, Western Electric Company. v M. Godwin, Public Utilities Section.
F. Grant, Paper & Pulp Section.
''
uuiv Gun.nF.RT, The Pullman Company',
u.ui Hale, The Atchison, Topeko & Santa Fc Ry. Co.
ajok Bolling II. II.\xnv, Richnioud Safety Council.
T. Haiuii.ycto.v, U. S. Bureau of Mines.
C. IIavkn, Vehicle Fleet Section.
W. Ilnss, Textile Section.
. T. lli.i.i.Mum, Chicago, North Shore S; Milwaukee R. R. Co.
harms E. Hut., Nov Yotk Central Lines.
.
ov. IIahui.h <I. I (hitman, Governor nf New Jersey,
i. w/iii: J. Holding, Albany Safety Conned.
isvtN A. Kayskk, St. Louis Safety Council.
itOMss P. Kearns, Industrial Comuiisduii of Ohio.
. T. Killer, Detroit ImliHtri.il Safety Coiiueil.
a V, Kepnek, Pennsylvania Salt Mig. Co.
iii.ivm C. Kxoi.t.k, Street & Highway Trnllic Section.
L. LaFountainf, Great Northern Railway Co. . F. Larson', Missouri Pacific Railroad Company.
mon Lazarus, Safety Council of Columbus (O.) Chamber of Commerce.
E. Loxc, The Delaware & Hudson Railroad Carp.
R. Loyo, Safety Die. Birmingham Chamber of Commerce,
nos. II. MacDonald, U. S. Department of Agriculture.
. T. McArthur, Peoria Safety Council.
. J. McCann, Meat Packing, Tanning & Leather Industries Section.
Officers and Directors
Miller McCuntock, Harvard University.
'
T. H. McKenney, Carncgic-Illinois Steel Corp.
A. D. McWhorter, Safety Div., Memphis Chamher of Commerce.
If. T. Martin, Fisk Rubber Company
F. W, Matson, Minnesota Safety Council.
J a sirs R. Mays, Elizabeth Safety Council.
E. J. Mkiihen, Portland Cement Association.
I. W. Mu.i.ard, Industrial Gloves Corporation.
Ja.mf.s K. Miller, Grand Rapids Safely Council.
Leslie. W. Miller, Superior Safety Council.
Harold L. Miner, E. 1. du Pout de Nemours & Co.
Lawrence M. Moore, Eastbay Safety Council.
.
R. B. MoRLEY. Industri.d Accident Prevention Asstis.
CEOiir.E C. A. 6im, The Detroit Edison Company.
George OpfEN^j,EiMER, Kansas City Safety Council.
Lew R. Palmer, Equitable Life Assurance Society.
David A. Patton, Newark Safety Council.
Charles XV. Peacock, Safety Div., Milwaukee Assn, of Commerce.
C. E. Pettiuone, American Mutual Liability Insurance Co.
Gen. Gf.orce B. Pili.sdurv, United Slates Engineer Office.
Arthur Potterton, Hudson County Safety Council.
W. D. Price, Employees' Publication Section.
J. A. Purdy, Wood Products Section.
Albert S. Recula, Industrial Relations Counselors, Inc.
Lt. Col. Henry A. Reninger, Lehigh Portland Cement Co.
Marinus Riter, Paterson Safety Council.
R. B. Roaper, Petroleum Section.
A. V, Romvf.DER, Duluth, Missabe & Northern Ry. Co.
George E. Sanford, General Electric Company.
Henry G. Schaifner, Erie Safety Council.
`
Roimiir L. SciiMtrr, Louisville Safety Council.
Karl G. Sc11of.ffj.er, Rahway Safety Council.
Harry A. Schultz, United States Steel Corp.
Kami, S. Shaiitzeu, Utica Safely Council.
Ray If. Sheets, Madison County Safety Council.
Gen. John II. Siikkiiurni:, Massachusetts Safety Council.
IJr. L. A. SiiouiiY, Bethlehem Steel Company.
Ernest L. Simonus, New Haven Safety Cotiueil.
Judge Lf.e E. Skkkl, Cleveland Safety Council.
C. XXL Smith, Standard Oil Company (lud.).
Edwin C. Smith, Dlnckstone Valley Safety Council.
XValter Dent Smith, Delaware Safety Council.
W. A. Snow, Construction Section
R. T. Solknste.v, Elliott Service Company.
E. C. Spring, I.ansdale, Penna.
George R. Stephens, Safety Bureau, Buffalo Chamber ol Commerce.
James M. Strike, St. Joseph Safety Council.
Arthur M. Tode, Consulting Marine Engineer.
Harold M. Toombs, Refrigeration Section.
he
TNatit
the first, Industria the scssi Section ;
All: The sm< It cover request.
Ma Transa< visory For th< quoted
over, S
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of the divisio ter an other speed comp
addre Safet cases are o
cuss com expi - pap'
S Twenty-fourth Animal Safety Congress--National Safety Council
W. W. Trench, Schenectady Safety Council. W. D. Turueville, San Antonio Safet)' Council.
E. J. Wallman, Power Press Section.
Dr. C. H. Watson, American Telephone & Telegraph Co. Harrv M. Webber, Illinois Bell Telephone Co.
Albert C. White, Jr., Springfield Safety Council. S. E. Whiting, Liberty Mutual Insurance Company.
A. W. Whitney, National Bureau of'Casualty & Surety Underwriters.
T. A. Willson, Accident Prevention Equipment Manufacturers' Section. W, II. Winans, Union Carbide & Carbon Corp.
C. T. Winegar. Automotive & Machine Shop Section. Harry Wise, Sr., Chattanooga Safety Council.
J. M. Woltz, The Youngstown Sheet & Tube Co. W. E. Worth, International Harvester Company.
E. J. Zauet, Safety Bureau, Duluth Chamber of Commerce.
-
Earl W. Zimmerman, Safety Div., Syracuse Chamber of Commerce.
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.mittee-
Occupational Diseases
Occupational Diseases
.
i . FRIDAY MORNING SESSION -
October 18, 1935
The session *vas called to order by Mr. \V. Dean Keefer, director. Industrial Division. Xational Safety Council. Dr. C. H. Watson, ncwiy-eicctcd President of The Xational Safety Council and Medical Director, American Telephone and Tele graph Company, Xcw York City, presided.
Present and Prospective Occupational Disease Legislation
By F. ROBERTSON JONES
j General Manager, Association of Casualty and Surety Executives
,,..
New York, N. Y.
'
Sh'tcc iGc prevention of diseases is, to -some decree, a community problem,
the state ought to do its part toward the prevention of occupational diseases, along
with all others. The. public health authorities should study the causes of such dis
eases, their prevalence, virulence and the means ior 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 rules. Statutory regulations tor prevention,
emanating from other sources, such as are common in "labor" or "factory" laws, have
too serious drawbacks to he etheient. They are apt to he indexible and quickly become
. "out of date"; and they arc too apt to he perverted for die establishment of fictitious
. ' bases for wasteful and demoralizing damage-suit litigation. Scientific bureaus ni
occupational hygiene, under direction of public health authorities, are the best public
instrumentality. Efficient bureaus of that character are now to be found in several
i, states; hut. generally, such public health organizations are inadequately manned and equipped. Therefore the primary need in occupational disease legislation is for
measures to improve our public health services.
. Emphasis should he placed on prevention, not merely because "an ounce of pre-
, vention is worth a pound of cure." but because public measures for the assurance of
relief to victims arc perilously susceptible of being so perverted that those affected
will tend to rely upon and abuse the protection afforded as a substitute ior, instead
, of as a .supplement to , means for self-protection.
<
Expert opinion now calls strongly for the entire elimination of employers' liahility
for "damages" for occupational injuries--by disease as well as by accident--based
upon negligence. That remedy is too uncertain in operation, litigious, demoralizing
and wasteful: it furnishes relief to too few of the victims unless it he so liberalized
as to he grosslv unjust and financially perilous to employers--and thereby harmful to
industry and ail dependent upon industry.
..
Losses from ill-health among workmen are primarily subjects for self-providence
or for "social insurance"--tor "sickness insurance" to help out during brief illnesses,
and for "invalidity." "old age" and "widows' and orphans' " insurance where illnesses
or infirmities result in long or permanent disability or untimely dcalth. The cost of
these insurances against the common misfortunes of life cannot rightly or expediently
be imposed wholly upon industry, but needs to be distributed somewhat in proportion
118 Twenty-fourth Annual Safety Congress--National Safety Council
In resi vnsibilili. And benefits, at a high scale of maximum earnings, as in workmen's rnini'c! ration. simply cannot be provided for all such workmen's misfortunes. In im.did y. old-acc and life insurance, at least, the benefits must be graded, more or less in iroportion to the individual workmen's contributions to the requisite reserves; and the right to benefit must lie conditioned upon some minimum number of contribu tions. It is only for some relatively small proportion of the injuries and physical ills to which workmen are subject that it is reasonable and practicable to impose the full responsibility on industry.
I rom its higiimings. the workmen's compensation law has covered all injuries to
lic.dih resulting from occupational accidents. Further it has now, in this country and
abroad, been extended to cover many specified diseases, not resulting from accidents,
classified as ''occupational.'' And in a few states in this country and Latin America
it has been extended indefinitely further to cover "all inclusively" all injuries to health
"arising out of and in the course of the employment" or all "occupational diseases,"
undefined, "arising out of the employment."
In this country there is strong political pressure in favor of this "all inclusive" (oirrage of injuries bv disease based upon the contention that there is no difference in principle between "injuries by accident" and "injuries by disease"; therefore, indus try 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 arc that industry shall be held responsible and liable to compensate for the losses from those iniurics only which are caused by "trade risks", resulting from employment and which the employer can control; and that the liability for such risks shall be sufficiintly well defined as to be insurable at practicable and equitable rates, fixed in alliance. The standard compensation laws have been framed to carry out those prin ciples in application to injuries by accident. P.ut 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 i a Sudden event, happening at a definite time and place. Generally the can-al il lation betw een the rniploi mrnt and the accident and between the accidrnt amt the resulting injury can be traced with reasonable certainty. Generally the impbner is anlomatieallv identified. And there is a char-rut event from the date of which limc-ii.uits 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 haimful results. In silicosis there may be an interval of as much as Iwiulv or thirty scars between the first exposure and disability or death.. In the mranlimr. many causes for disablement nr death, other than the occupational disease mas hair operated. Often it is a mailer of extreme difficulty to determine whether disability or death really has resulted from an occupational disease or from other ram i s. Medical diagnosis of the mere existence of a particular disease is often uncertain; vet 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 cause-, and eonseipieuees.
A (miller difficulty is that, while the disease is of slow contraction. it may lie cohti aeti d In- a workman iimli r several different employers nr insurance carriers. In sin b cases it is essmtial for the protection of the workman that some one existent lanployi v or iiiMWaiicc carrier shall be direellv liable for the entire rompriixuliou. That ,'.s a lupin l.r vicarious and bar b liability In impose upon an employer or insurer - who her or not m eoiiipani'd by a l ipid to claim contribution from callin' employers and ie.a'iri-rs and. in all fairness, should he subjicl to strict limitations.
M-aoilier tin re is a dillu ulti iniiilinl.d to the provision of new insurance for romp' u-alinii for such ilisi asi s of slow eoiitrai lion as silicosis, l huler stu b conditions,
the li il 'lily imposed upon the i mploni im ludi s a liability for disability or death in the filin' e; in oilier words, a liability, not merely for future risks but also for the cost of a volume of physical impaii mints already inclined (hough the liability therefor is not yet Mialurcd. In insurance parlance, these arc termed "accrued liabilities." Such aceimd liabilities, under a law new ly imposing a liability to compensate for silicosis, would, it is estimated, in a stale such as New York, aggregate many millions of dollars. This cost is additional, to losses front current risks; and how In meet it and how to fix' reasonable charges fur insuring it is a complex financial problem.
Occupational Diseases
110
The situation, then, in my opinion, is this; The principle of compensation, re
gardless of fault, may well be extended to cover those disabling diseases that are
characteristic of and peculiar to and have their origin in the occupation or process in `
which a person is engaged. This would exclude the diseases of ordinary life, and
would he applicable only to the specific hazards which arise out of ami because of
industrial processes and occupations. The provisions for such coverage should be
separate and distinct from the provisions of law applicable to compensation for nrri-
dcntal injuries, and these distinctions should he constantly emphasized. The problem*
.- of formulating such provisions is relatively simple with reference to those recognized
diseases set forth in the older occupational disease laws, since such diseases are
reliably diagiinsahlc, of quirk contraction and non-progressive. Huf it is difficult in
respect to such progressive diseases of slow contraction as silicosis and a.'bi sp.sis--
now generally regarded as being truly "occupational." Fortunately, however, llu-rc
are promising models for our guidance in some of the foreign compensation laws,
whereas experience under indefinite, "all inclusive" coverage in Connecticut, Massa
chusetts, Wisconsin and California is helpful with lessons of faults to avoid.
In my' Opinion, a law fur the compensation of occupational diseases should contain , provisions |o the following effect:
1. DW'ases to be made "compensable" should lie distinctly specified--by lislinc
. in a "schedule" or otherwise. They should include all those diseases, but only those,
to bf found in the stale, which, according to prevailing medical opinion, can be traced,
in individual! cases, to origins in "trade-risks"--i. r.. risks, not of ordinary life, but
created by special practices or processes in industrial occupations.
2. There should lie 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; the time within which, in
order to lie compensable, disability or death must follow exposure should be limited;
and eases resulting from exposures prior to the effective date of the compensation
coverage, or in industries wholly outside the particular state, should be excluded.
4. Prompt notice either of the first manifestation of the disease or of disablement --the time of such event to lie determined as a mediral quesliou--should be strictly required: and every presumption should be against the validity of a claim not made
as promptly as practicable.
5. Til ease an occupational disease merely aggravates, prolongs or accelerates
disability or death due primarily or proximalely to a non-nrcupatiounl disease or
infirmity or. above all. to old age. the compensation should be reduced to be propor
tionate to tbt- degree to which the occupational disease contributes to the disability or accelerates death.
fi. `The employer, as of the lime of the workman's last substantial exposure to
hazards of the disease, and the insurance carrier then on the risk should be liable for
the entire compensation--with or without right to contribution from earlier employers
and insurers. Put all such liabilities, whether direellv. for compensation or for con
tribution to the compensation payable by others, should be stibjeel to brief time
limitations.
7. In incurable diseases, especially silicosis, the obligatory medical benefits should
be specially limited in time and kind.
*
R. In silicosis and other diseases of slow contraction. there should he special
provisions for limited compensation to workmen laid off before actual disablement,
with the alternative, under .some conditions, of waiicr of rompen-ation by surh work
men for aggravations resulting from being allmml to eoutioue 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
dale of its enactment and that when it shall take clTcct; the compensation fur such
diseases should be specially reduced and limited below vvlial would otherwise he
appropriate until the "accrued liabilities" are worked off.
10. Cnm|iriisati.in fori occupational diseases should be insurable separately from
compensation for accidents: and. in the initial stage, at least, of a regime of com
pensation for snrli diseases as. silicosis, the rating practices now imposed upon insur
ance carriers need to lie radically modified..
.'0 Tuvnly-fourth Annual-Safety Coinjiess--National Safely Council
The ;il>o>e }irrigrani is somul and would Ik highly conducive to occupational ace prevention. Hut f am not so confident that it would lie safe. The pressure is ng for "liberality" in compensation laws. Merely a few among a large munlicr i roltahlc slight diversions from what I suggest would convert compensation for ipatioiial diseases into indefinite health, old-age and life insurance for workmen in .) industries. The cost might ruin the industries, and, at least, would he so deniable as to make the risks "uninsurahle," except on the unlimited assessment oi. with all its financial perils and uncertainties.
In regard to prevention, there are still some practices to be decided upon in 'cling a regime of compensation for occupational diseases about which there ins much doubt. Tor example: Such a regime will practically compel employers, iiing employment, to discriminate against all the ailing or aging--against all pi the most healthy and robust. That seems to lie desirable in occupations when occupational disease hazards are great. Hut is it desirable otherwise? Again, an ideal common to those of us who emphasize prevention is to rerpiirc prompt leiinnal from exposure of workmen manifesting the first symptoms of ail ipaliou.d disease. Hut for the elderly or skilled workman the loss of his trade-job
he woise. in every respect, than the danger of continuing his cN|>surc. How . should such cacs be defined and treated and how should the law he framed to . t or induce si eh treatment? Political impatience is the chief obstacle to a just and equitable settlement of the ip.itiou.il disease problem. If those thoroughly informed as to this complex snh-
wlm have sincerely at heart the welfare of workers could be delegated the auity to devise a Solution, some progress might he made. But when political gamin is injected into the situation there is little chance for an adjustment `.ictory to all concerned. The greatest need today is the divorcement of occupad disease legislation from politics or political considerations.
Some Practical Considerations in Dust Control
By J. J. BLOOMFIELD
a-jitary Engineer, United States Public Health Service, Washington, D. C.
The |u vention of occupational diseases due to the inhalation, of industrial dust i iuiarily an engineering problem. Until recently, however, little attention had.
devoieif to the control of dust, accounting for the paucity of fundamental data `ubjvt. The consequences of the neglect to furnish adequate protection from hazards >rc now being fell, and the cost is becoming a serious drain on industry, m.w wi I established that exposure to certain kinds of dust, such as those con ag considerable amounts of quartz, has increased the morbidity and mortality from respiratory diseases; while metallic dusts, such as lead and its compounds, been associate i| with general systemic poisoning of workers. It is obvious, hire, that any serious attempt to cnnlrnl the dust hazard should, in time, result nly in the improvement of the health of workers, hut also he of definite economic l to industry. 1 he hem-fils of a preventive program in the field of accidents are well known, irv is fast realizing the need of a similar picvcntivc program with respect to ition.il diseases.
Evaluation of the Dust Hazard
I he first step in the evaluation of the dust hazard is the determination of tile ational exposure to the dust in question. A typical example of such a study serve to clarify the methodology involved. 1 able 1 shows the various occupations in a granite quarry and the number of rs cmplmed in each occupation. Drillers are the only persons using pneu-
tools, known to. produce considerable quantities of dust. In other words, 38 ^ ut of thy quarry personnel arc shown to lie exposed to a potentially dangerous
izard. Jin. xcupatioiial analysis at once indicates that the dust investigation
Occupational Diseases
121
Table 1--Occupational Classification of Granite Quarriers
Occupation
.
Number in Each . Occupation
Drillers:
l-cyncr ................................................................................... Plug and jack hammer......................................................
,
Other quarry employees:
Superintendent ................................................................... Foremen ............................................................................... Compressor engineer ........................................................ Hoisting engineers ............................................................ Locomotive engineer ........................................................ Locomotive fireman .......................................................... Steam-shovel man ............................................................ Cr-r.ttpc' opera.tor. .................:................................................ Derrick men ....................................................................... Muckers ............................................................................... Blacksmiths ......................................................................... Tool hoys ............................................................................. Water boys ......................................................................... Machinists ........................................................................... Air-line repairers ..............................................................
ripe fitters ...........................................................................
1 7 1 12 * 1 1 I* 24 24 6 2 1 2 1 2
Total.................................................................................
Table 2--Occupational Dust Exposure of Granite Quarriers
Number
in each'
Occupation
occu pation
I cynrr drillers.......................................................................... Plug and jack-bainnicr drillers (quarry-hole)...............
17 37
Plug drillers (yard)................................................................ All other workers.....................................................................
83
Dust counts in millions of particles per cubic foot of air. Weighted Average
144 4 112.1 36 9
5.8
should especially concern itself with these workers. 'The next step involves the di termination of the occupational dust exposure. Table 2 shows the results of such
a study. It is apparent in this table that the drillers arc exposed to high dust concentra
tions, especially the I.eyner and jackhammer drillers working in the quarry hole. From a further analysis of the occupational dust exposure of drillers it is possible to determine which activities' are responsible for the dust. For example, experience has taught us that the various activities comprising the processes id most dusty occupations arc usually associated with dissimilar dust exposures. Fur this reason it is essential to estimate the amount oi time spent in each activity in any one occu pation and to determine the dust exposure for each. Table 3 shows the results of
such a study in the case of a I.eyner driller. It will be seen that a Leyncr driller has five different dust exposures. A differ
ential analysis, as presented in Taldc 3. yields several valuable findings. First, it enables oiic to obtain a true average dust exposure for workers engaged in the occu pation of I.eyner drilling. (In this case the weighted average is 144.4 as contracted with 213.4 million particles per cubic foot found during drilling operations only.) Second, it enables one to determine which activity, or activities, contribute most to the
12 Trrenty-fninlit Annual Safety Congress--National Safety Council .
Table 3r--Summary of Dust Exposure of Leyner Drillers in a Granite Quarry
I \rtiviiy
Average '
dust exposure
Particle-hours
in millions of
Number of
in millions
particles per cul>ic hours spent in
per cubic
foot <f air fa) each activity (b) foot (a X h)
illint; ...............................
.n**if................. itcliim: `Iritis................. .'u'liin'r ........................... ............... wim; nff 1mW`............ ...............
GO 1.085 0
4 853/. 1 9.8 2 I GO
A 4 5 'A 271.3
T..iaf............................................
8 1,155.2
155.2 panicle limns in mil I <ns per cubic font
8 Ilnurs
" 1 -1-1.4 million particles |irr cnliic font
! -| hazard. It^is evident th.it the practice of blowing off holes by meins of inserting
[ compressed :o. line into each hole is attended with a great amount of dust; and
neli this .activity lasts hut 15 minutes of the 8-hotir working day, it is responsible
r 25 per cent of the total dust exposure. It is evident that 25 per cent of the I.eyner
iHer s dint exposure may be at once eliminated by prohibiting this practice. And
-ily. such an analysis indicates the necessity for devoting all one's efforts to the
nun.il of dust during the drilling process, since this activity accounts for 74 per cent
the tnt.il dust exposure, nhliGugli a f.eyncr driller spends but one-half of the rl ill" day at hi' drill.
So iar i line dealt with an industry in which the workers, as a rule, do not
i nigc their occupation. Often workers have had several occupations, either in the
me industry or in several different kinds of establishments. If the worker has been
upb.vtd in various occupations in the industry, it is a simple matter to determine
' total dipt exposure in that industry. This is important from the viewpoint of
i relating a worker's dust exposure and his clinical condition. A typical example is
mi in Table 4.
'
Table *.--Total Occupational Dust Exposure of an Anthracite Coal Worker
Oi npntinn
ate pieki r ................................ ............. ItliiT ................... ill- `Ii is ( r ....................... ;,..
I.iImiht .......................... ............. iiicr ............................................ itiou (nminn ....................... .............
Total.......... ......................... .............
Number of years in
orcnp.ilinn
2 9
3
5
_
30
Dust conccntration in millions
of particles per cubic fnnt
380 71 71
' 480 ISO
.7
. ,. .
Millions of particle\c*nrs pet cubic foot
700 112 213 1.4 in 7 200 35
--
9.79(1
"0 millions oi particlc-ecars per cubic foot 30 years
millions of particles per cubic foot
I i I able 4 the worker's occupations are arranged in the order of employment, e lasr one living his present occupation. Il is obvious that had one Considered this upaiion only, the dust exposure would not have yielded a true stale of afTairs,
Occupational Diseases
123
nor would il have been possible to correlate this dust exposure with the man's clinical . picture. In the above technic, correct weight is given to the number of years spent in each occupation and the dust exposure associated with each. Only by such an analysis is it possible to arrive at a fair estimate of a worker's dust exposure and bis proper designation. Such an analysis is justified by the fact that results obtained with this technic yield excellent correlations with the climco-rucntgcnuhigical studies in inducted on anthracite coal miners/
It is thus apparent that there is more to engineering dust surveys than the taking of dust saniples-and their analysis. Owing to the tact that the making of dust studies is rapidly being adopted in industry, it lias seemed necessary to emphasise the impor tant factors in such investigations. Although the making of dust counts, per sr, is not a difficult,, procedure, the collection of dust samples in industry and their proper interpretation should be done by a thoroughly trained investigator. '1 be examples .just given show the value of this technic in the subsequent steps to be taken in the control of the industrial dust hazard.
'y.`
General Dust Control Methods
The selection of any method of dust suppression will depend primarily upon its effectiveness 'tie reducing a given hazard and its adaptability. A large percentage of reduction in dust docs not necessarily indicate that the method u-cd is rlliricnl. unless the reduction has actually been sufficient to bring the exposure below the safe limit, and does not interfere with the industrial operations involved, fit general, there are four methods of dust control: (1) substitution of nondust-pruducing or harmless sub stances; (2) isolation of the dusty operation; (3) wetting the dust at its source; (4) local exhaust ventilation. These methods may be supplemented by personal respiratory protection.
The first method lias a limited application. One example is the use of a noilsilica parting compound for a silica compound in connection with the making of foundry inulds. Table 5 shows that although the use of parting compound, in thi particular study, only necessitated an exposure of 54 minutes of the 540 miimtrs ol a iiiuhlcr's work day (10 per ccnlj, actually this activity accounted for approximately 5S 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 dust hazard in this instance to a considerable extent.
Table 5--Dust Exposure of Molders
Activity
Average Dust
rExposure in Millions
'l ime of Expo-
of Particles
sure in minutes per Cubic Foot
00 (b)
ll>e of Parting Compound............ ..
luiiiaiiiing tasks in molding........ ..
1'miring ........................................... ..
IbmtpiiiK tiiubls
.. ..
51 412
58 1G
(13.8 4.4 31
32.5
,
ParticleM inutc* in Millimi'
(a X b)
3,445 1.813
ISO
530
Total.......................................... ..
540
..
5.05S
5058 million particle-minutes
------------------------------------------- ---- 11.0 million particles (per cu. ft.) 540 minutes
Ii\. 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
use of a material not as toxic ns sand.* Table G shows the improvement effected by
this t>pc of substitution. Not only is the dust concentration reduced from an average
of 9G9 to1 155 million particles per cubic foot, but the potential exposure to quartz diM
is diminished from 42-90 to 3 per cent.
'
' \
I Twenty-fourth Annual Safety Congress--National Safety Council
Me 6--Showing Reduction in Concentration and Quartz Content of Dust in Sandblast Rooms With the Substitution of Steel for Sand Abrasive
c nf axis c
Average dust concentration
. in millions of particles Percentage
per cubic foot
of Quartz
960 -12-08 155 3
The secniiil method of dust control, isolating the dusty process, possesses many ibilities, but unfortnnalelv is not widely used. The theory underlying isolation concentrate the dust sources to one locality or to a single closed space. In this . a minimum number of cmphoccs arc exposed. At present, many foundries, durshal.e-oul expose workers who normally are engaged in occupations with low ! ronn-ntralions. Thus, mohlcrs in a foundry may he exposed to a dii't concili um of 3 million particles per cubic foot under normal occupational conditions, hut u shal e-out operations arc carried on close by. their exposure may he increased norc than 50 million. The same condition exists when annealing flasks containing aid slag arc emptied in malleable iron foundries, exposing grinders and tumbling el nlUmlauts at work close by.
lYihups the I-.-si example of isolation of a dusty process is the abrasive cleaning n. This completely encloses a hazardous process and exposes only the blaster who i ncrally cipiipped w ith a protective helmet. The room is also exhausted, which her reduces the diot ronrentration. Processes which are isolated require good datum. Oilu-r examples of isolation are the automatic turnlahle for abrasive ling, lijinhling barrels, and hatch-mixing rooms found in some pottery cstablish-
Ttic third method, perhaps the oldest known, is the practice of welting the dust x source. In Table 7 an example is depicted in connection with the drilling and mg of rock in anthracite coal mine operations." It is apparent that a tremendous ctiou in dust has been effected by this method. However, ns already pointed out, -x a particular method is attendant with a reduction of the dust to a safe limit, imot In- cnuxrdt-rcd successful. In the present instance, the workers engaged in ng are still exposed to unsafe concentrations of a highly dangerous dusUand norc po-itivc method .of controlling the dust in drilling operations by dust traps d he indicated. For drilling and loading operations involving an exposure to dusts toxic an those containing high amounts of free silica, as in the ease of coal or in tali . the reduction shown by the use of wet methods may be considered live.
!c 7--Ci ntrasting "Wet" and "Dry" Methods of Rock Drilling and Loading
No. nf Samples
Average dust count in millions
of particles per cuhir foot
"Dry"
"Wet"
mg
23 568
33
mg
10 636
32
rite fourth method--cxlinml ventilation--is perhaps the most effective, and one the widest application. We cannot discuss here the details of the theory and ii of local exhaust systems, except to point out there is a real need for more
.mental studies nf the tvi>e cmdmlrd by DallaValle with reference to the ilexigu 'aI exhaust hoods, which he has presented in Public Health Pulletm 217. Th~
of Hatch and his colleagues' op the control of the silicosis hazard in the hard industries is another example of a scientific approach to the dust elimination
i
Occupational Diseases
125'
Table 8--Summary of Results Contrasting the Dust Exposure of Mine Workers Under Controlled and Uncontrolled Working Conditions
. Operation
Dust Concentration in millions of particles per cubic foot of air Controlled Uncontrolled
Remarks
.
1-iiing charge .............. -10
Loading coal or rock.. 32 Loading coal .`..-x-j........ 4-26 i hilling........ .................. 33
Hauling coal in Quines. 1.2 Preparation of coal... 24
834
636 291-1138*
568
17 380
Unless at least 15 minutes elapsed after firing a charge, miners found to be exposed to high dust concentrations.
lly welling the loaded material the dust count is reduced as shown.
Mechanical loading decreases the dust cxpoxnre as iniliented.
Wet drilling is effective in reducing the dust concentration. Further reduction would necessitate exhaust ventilation.
Welting coal and empty cars reduces dust in liatilngcways.
Wet breakers reduce dust counts as shown.
'I he low er icmjW is iib'itcialci witil lliC ll.THtl I ailiuc of wet coal while the higher avcta^c
It is apparent that there are no set rules for the mechanical protection of workers from the industrial dust hazard. Specific conditions in an industry, or a plant, will determine the type of protecting to be employed. The present discussion has empha
sized the importance of approaching the problem from the standpoint of the occupa tional exposure. Studies in representative plants of an industry often reveal the various methods which may lie 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 meiliuds arc not known and practiced for the iliminalion of the dust hazard in this industry.
Another example is indicated in the results of a study now in progress in connec tion with mcrciirialisni among wurkers in the hatters' fur cutting industry. Table 9 shows the exposure to mercury dust and vapor of some of the workers in this industry
Table 9--Exposure of Hatters' Fur Workers to Mercury Dust and Vapor Under Controlled and Uncontrolled Conditions
Occupation
Total Mercury Exposure in Milligrams per 10 cubic meters
Uncoiitrolle d Controlled .. ^
.................. Shippers ......................... ................. Cutlers ........................... ............
4.6 7.2 4.0
f.8
................. ..........
................... ..................
38 1.7 31 12 2.5 06 1.5 , 07
Method of Control
None practiced
Local exhaust venti<lation <
Segregation H
)
126 Tncnty-fourth Annual Safety Congress--National Safety Council
under controlled and uncontrolled working conditions. It is apparent that where
sonic measure o( control is practiced by such methods ns segregation or local exhaust ventilation, a material reduction in the exposure to mercury has been effected. It Is
our belie! that in the ease of the blowers' exposure, a reduction may be effected by
mechanical enclosure and local exhaust ventilation, and that the shippers' exposure to mercury vapor may be lessened by a general system o! ventilation sufficient to change the air in the store room frequently enough to bring the mercury conccntra-
tratioii to ajower let cl. Unfortunately, in the present investigation, it has been im
possible to find a plant in which an attempt has been made to reduce the exposure for llic-c two occupations.
In some dusty occupations the methods of controlling dust have not been devel oped. In fact, operations such as removing the cores from very large foundry castings,
sand-l^isiing, handling of used storage battery plates, paint chipping, and cadmium
oxide lanuf icturc appear to offer no practical means of adequately controlling the
du-t generated. Its such cases, it is therefore necessary to furnish the worker with persona' respiratory protection devices to prevent his exposure to the harmful effects
of the i lists present. These devices consist of various types of respirators, masks,
and hell rets.
'
It is important to hold in mind the limited use of personal protection devices.
Because a worker cannot with comfort wear a mask or helmet continuously, such devices must be employed intermittently. Their use is generally extended to (hose
operations where all other methods have failed or supplementary to them, as in
storage battery repair where the exposure to small amounts of lead breathed is known to be detrimental to health.
It should be pointed out that the U. S. Bureau of Mines is equipped to conduct
approval tests oi respirators used for protection against various dusts and fumes
(Schedule 21). These tests are conducted against the dust for which the device is to he used and arc 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 /luring the sandblast investigation conducted several .wars a::o by the Public Health Service in cooperation with the National Safety
Cv'UKil, showed that the only practical safeguard to the worker inside the 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 vyas found that a relationship existed
between the amount of air supplied to the helmet and the concentration of dust
in-ide 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 vvhilc varying the air vulumc. at the same time maintaining the dust con.-itti:( ,11 ill the sandblast room (outside the helmet) constant. The positive supply
"f 6 cm. ft. if dust-free air per minute will protect a worker under the operating
conditions^ now in practice in sand-blast rooms. T he ultimate criterion of protection,
liuuever, 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 the 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
enu "gnod housekeeping" has been interpreted as signifying only the periodic removal d dust collected on floors, rafters, etc. Although such practice contributes to the
general state of cleanliness of a workroom and should always be in force, the time
ias sin civ come'when serious attention should lie given to tiic installation and rigid naiiilcnnnce of all types of dust control devices. In rvery plant there should be
mne iciponsiblc individual charged with the periodic inspection of all workrooms ci to sanitation, ventilation, and maintrnanre of all dust removal and other protective
Icviccs. Perhaps the best criterion of the effectiveness of these devices is the
rriodie determination of the dust content of the air at the workers' breathing zone. ,inly by constant vigilance and an approach to the problem as outlined in this paper lay owe hope to make progress in the control of the dust hazard in industry.
Often the Ixnefils of even a most extensive program of dust control arc not
nmediatcly realized. This is especially true in dealing with fibrosis-producing dusts
i plants where some of the workmen have already inhaled sufficient quantities to
Occupational Diseases
127 J
cause disability. However, in dealing with such dusts as lead, cadmium, and mercury compounds, control measures may produce salubrious results in a relatively brief
period. It is difficult, because of lack of sufficient reliable data, to indicate here the economic benefits resulting from a preventive program of dust control. It has been estimated by Dean K. Brumlngc. statistician of this office, that the minimum expectancy in savings to employer and employee from an indicated reduction of the accident rate and of the time lost on account of illness (or an equivalent reduction in mortality), demonstrated as attainable, is 520.000 per year per 1.000 employees. And this estimate is for plants whose accident rate is considerably below the average, in which there arc no occupational health hazards. In plants where hazards arc known to exist the savings should be far in excess of this conservative estimate. When one realizes that in this country there are approximately 15 millions of workers engaged in manu facturing, mechanical, and mineral industries, then it is evident that the magnitude of the problem has not been overemphasized.
, References
>*.'
..
.
1. Jlloonificbf,' J. J. ami J)rccsscn \\\ C.: Silics-'U iimoiti; jimmle quariie*. Public Health
Reports, Vol.
No. 23, June 8. 1**31. #
...
2. AntbmcwfKiHcosis among h.ird coal miners. Public Menhir ttulltlm No. 221, VMS.
3. liluomHeld, J. J., ami Crccnburc, Lcou.iaK S.iml ;m<l metallic abrasive blasting ns an
mduttrin) health hazard. Jour. liul.
\nl. I5, tm. 4, July, 193.1.
.^
4. Match. tl*hxotlme, Hi inker, 1`htlip, and Choate. Saiah 1'.: Control ol the silicosis hazard in
the hard-rock iiplustiies. I. A. laboratory study ! the dc<-inu of duM control systems for u*c
with pneumatic granite cutting tools. Jour. Jnd. ]!>., v*l. 12. no. 3, March, l*Ul).
Match, Theodore, Kelley, Oeoi^e S., and Kcl.ncl, J.\V.: Control of the Mltco-is hazatd in
the hard-rock industries. II. An investigation ! the Keller dust trap lor uc milt pneumatic
rock (bills of the "Jack-hammer" type: Jour. Ind. My*p. vol. 14. no. 2, l ehruary, J932.
Match, Theodore, Warren, Henry,, ami Kelley, (ie-u^e S.: O-uiiol of the silicons hazard in
the hard-rock industries. Ml. Dcmk*i and upciatmn <d a dust-control system for u^e with
pneumatic rock drills in open excavation. Jour. Ind. lKp., vol. 14, no. 7, September, 1932. ^
r'-
Silicosis and Silico-Tuberculosis Medical Problems of an Important Industrial Disease
By EDGAR MAYER, M.D.
New York City
A hidden element of the cost of production is industrial disease.' Industry has
reached a stage beyond the concern only of wages and hours, bar more important
is conservation of mail power hv preventive medicine and improved engineering.
Disease preventive measures are nut a cost, Ini'., in the long run, a great economic
saving.
'
Incidence. In the United Stales it has been computed that llure are from 500.000 to a 1.000.000 people employed in occupations where a silicosis hazard exists.
In New York City there arc about fi5,UO0 such employees. In a representative group
oi granite workers in Massachusetts silicosis alone was present In about la per cent
ami silicosis complicated with tuberculosis in almost S per lent. I ubcrculosis was
the cause of death in over ime-lhird id the granite workers which is iour times the
incidence for tunics of 20 years and over in this country. In toumlry mm studied
in Massachusetts, silicosis was less frcquml lahn.il ') per Cent I and less advanced
in degree than in granite workers. The dotation oi exposure in foundry workers
with pncumoiioconiosis has averaged many more years than that required to produce
silicosis in ail industry such as gold mining. '1 lie tuberculosis hazard in foundries
is nearly as great as that reported for some of the other dusty trades, hilt the
figures are much lower than those of miners oi gold, silver, copper and lead, among
whom the mortality from tuberculosis is S to IS times the general expectancy. Death
rates for alt noil-tuberculous infectious have been repotted higher among workers
in siliceous dusts than in the general population. It is suggested that the worker
in silica succumbs more often to acute pulmonary infections rather Ilian surviving
the chronic fibrosis.
.
'x Twenty-fourth Annual Safety Congress--National Safety Council
*
Silicosis is defined as a pathologic condition of the lungs due to the inhalation
-diva, whether free or combined in such a state ns to he capable of setting tip its
: ictcristic pathogenic clTccts. The principal factors that determine the incidence
dicosis arc (1) the percentage of free silica in the inhaled dust; (2) the con-
'alion of silica parlidrs less than 10 tnicra in diameter in the atmosphere; (3)
duration of exposure to the dost, and f-t) the susceptibility of the individual
need as modified by age. complicating infections, etc. The occupational disease
illing from such inhalation has been defined as "morbid results of occupational
^ ity iraceahlc to specific causes or labor conditions and followed bv more or
extruded incapacity for work."
"
Metabolism of Silica. Significant amounts of silica are present in all body us and fluids. It enters the body through the digestive tract and the lungs, t of that entering the stomach is eliminated in the stools, but a fairly large nut is absorbed intb the blood as shown by the constant excretion of silica in urine. All vegetable foods contain silicon especially the hulls of grains, hay and w. I he low silica content of the liver, spleen and kidneys indicates the little ulioii of the absorbed silica in the body. Silica content of the urine of animals
he influenced at will by diet. The body possesses a very efficient mechanism die disposal of silica because of the low kidney thrcshhold. Silica entering lungs in particulate form is expectorated in part with its enveloping cells, but t of it is carried into the pulmonary lymph channels. Many such particles reach l>nipli nodes and even the spleen by way of the blood. The finest particles ver, may be dissolved in alkaline body fluids and carried away in solution, to xcrclcd in the urine. There may he a constant drainage of silica from the throng t the inhalation of extremely fine particles of silica in dusty atmospheres, mall tint they are not seen under the microscope.
Attempts to influence the absorption of silica from the lungs by administration dkali have been inconclusive. Flimination of silica by way of the sputum front cuts having deposits of silica Jn their lungs appears to be higher than those ng no history of exposure to dust. Only small amounts of silica arc in the I and this level is little different in normals than in silicotics.
I'atliolorjy. 1 his disease is essentially a fibrosis of the lungs developing espey in such ir.u islrics as hard-rock metal mining, granite cutting, metal grinding sand-blasting. 1 he pathological changes arc believed to result front two causes, ocking of the lung lymphatics hv mononuclear cells laden with dust in addition he action of colloidal silica, the exact nature of which is in doubt. The small iclcs under 10 micra arc the only ones capable of penetrating the lung tissue.
Although silica plays the dominant role in the production of silicosis, the ad ore of other dusts tends to modify the pathological changes in the lungs so these resemble then those of other forms of dust inhalation, and the modification s some relation to the percentage of free silica in the mixture. Silicates, as in -tos, produce a definite change in the lung, as well as other dusts such as Ic. coal, etc. Such changes are represented hv a fibrosis brought about because ivcly insoluble minute particles of minerals in sufficient concentration have
brought by the activity of phagocytic cells into intimate contact with the onary connective tissue. This fibrosis is a diffuse cellular one that occurs in vails of the smaller bronchi and of all their finer divisions and extends to tc the supporting connective tissue of the adjacent blood vessels and to some t alse the walls of adjacent air spaces. However, when the great majority of nhaled .(articles arc composed of or contain silica, there develops, in addition, a lie and-localised type of fibrosis calk'd the silicotic nodule--an orderly whorlcd gciuvnt of cells and fibres, and with sharp definition from the adjacent purena. Ma. y dusts create a generalized fibrosis hut only one, namely one combined
silicon lioxidc produces the special fibrosis of silicosis. Scricitc, known as .'tinea, which is a hydrated silicate of aluminum and potassium, has not produced nmal experiments the silicotic nodule, but instead generalized fibrosis resulted,
bisls must he differentiated into those which arc cheniicnlly active and those i are inert when inhaled into the respiratory tract. Silica is a chemically active uhich must necessarily he soluble to a degree in the body fluids and its activity -da -.it its solubility. This activity which is manifested in the areas where dust
les are carried along the lymph stream by phagocytes, causes lesions of two
Occupational Diseases
1/fy
types, ``toxic" and "sclerotic" both of which have been reproduced experimentally. Toxic lesions depend upon local necrosis and slow death and appear to favor the growth of tubercle bacilli; the sclerotic lesions produce the nodular fibrosis. I he inert dusts are insoluble in body fluids and cannot exert chemical action in the lung tissue, but if they accumulate to a marked extent their eflect is mechanical which mat lead to a certain amount of diffuse fibrosis around the dust deposits. Certain dusts, such as carbon, may have physical ellccts, they may adsorb toxic substances and it has been suggested that on this basis there is a relatively lower incidence of aelite clinical tuberculosis in silico-anthracotics than in silicotic lungs.
Other dusts may even protect, as in the case of certain clays, gypsum and aluminum oxide. Pure pncuinonoconiosis may be only a laboratory disease, as the pulmonary fibrosis of workers in dusty trades probably results front the continued
action of dust and infection, whether it be tuberculous or not. In silicosis it is not the mineral particles that arc breathed in during life that
record the cause of disease, but the particles that hate been dissolved. lxisU to work, efficiency and health may be greatly accentuated through the inhalation of finely divided particles even of a chemically inactitc dust when there has occurred a lymph stasis which is known to follow exposure to silica. ThiS' lymphatic blockage leads to retention and accumulation of the inert dust. In soil coal miners who get what is called ``miner's asthma" we have this accumulation of carbon. Such patients arc very liable to have a high incidence of bronchitis with mechanical and physical changes due to retention of anlhracotic dust. Furthermore, unequivocal cases of silicosis, with or without tuberculosis, can no longer be doubted.
Tuberculosis. Most apical tuberculosis is acquired before the age of 25 and so silicosis at the age of 30 makes a previous tuberculosis more serious. Most workers with tuberculosis going into the mines before the age of 30 die of tuberculosis by the age of -15. The silicotic develops a sputum that contains tubercle bacilli late in life and the children who arc contacts with tubercular silicotics develop very little 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 diagnosis of silicosis is made primarily on two findings, the proper history of occupational exposure to siliceous dust and the presence of abnormal shadows on the pulmonary' X-ray. The physical examination and the patient's symptoms are of less \aluc. There arc other diagnostic aids such as the finding ui large quantities of silica particles in the sputum, quantitative determinations of silica in urine, and at post mortem, chemical analyses of the lung ash supplemented by petrographic examination, roentgen-ray spectrum analysis and special incinerating studies of lung
tissue. We must at times rely on the pathologist to determine the amount and distribution of fibrosis due to silica and from microscopic studies give an opinion
on the importance of this fibrosis as the ultimate cause of disease and death.
I .ting fibrosis may be present w ithout 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 Imt cannot he specifically identified with the siliceous material that it may contain. Accordingly the microincincratinn method of Irwin with hydrochloric acid is now included in the microscopic examination of any lung as a means toward a surer diagnosis.
Hiaeuuslic difficulties in clinical medicine may he more obvious if we examine first tiic occupational history. Quaitz grinders working under conditions oi massive exposure may develop silicosis in acute form even in a period of months, whereas in other occupations it may take 25 years. Workers in the same industry, indeed in the same room, experience different degrees of exposure dependent upon perhaps the dii'l-fi|tcring 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 pat tides of silica, as well as the dosage and total amount of *ilira. will influence the rale of development of the disease. Apparently particles that MV larger than 10 micra are not phagoeytosed in the lung. So a definite
)
.10 T'.veuty-f-'urth Annual Safely Congress--National Safety Council
lory iif expo-ore mint lie established :md in general hospitals where patients are gratory, c-unlitir>us uniler which they worked arc very vaguely described and
re are not available data on dust counts and silica concentration, so that the history often misleading.
As to symptoms, patients can perform strenuous labor despite extensive disease ml the sjinploins of dyspnea and cough are common to many diseases. Fever is nsent unless infection occurs, but most important is the great disproportion between
pntiuit's complaints and what is seen on the X-ray. the latter showing extensive normal shadows in comparison with the symptoms.
On physical examination, extensive disease may he present and few abnormal ujsical signs. The physical signs arc merely those of a general pulmonary fibrosis itit emphysema, such as restriction of costal and disphragmatic movement, diminum of or intensified breath sounds and a hyperresonant note. Rales arc usually sent nt 'ess infection is present.
As I" the X-ray, there are 3 essential types of shadows described, linear strands, nail disc etc shadows, and homogeneous shadows of varying sizes; these iorrei.inl to the fibrous strands, silicotic nodules, and the conglomerate masses
lihrnsis The nodular shadows arc usually characteristically around the him, or ( jnglomeratc nodular shadows of hat-w ing appearance extend into both per lung fields, or nodular shadows may he distributed in the upper two-lhirdt
the lung fields, perhaps more pronounced on the right side, with the lower third pt char lie emphysema. W ith infection present, the shadows are less sharp or c linear strands interconnect or fuse. Large conglomerate shaduivs appearing it from the liilum leaving the periphery of the lung clear throughout because of nphysenia. The distribution of some of these lesions may be determined by the Mure assumed by the workers, and infection may likewise determine an ultimate ; ideal distribution. Many variations from these patterns arc seen in the X-ray, pccially under excessive exposure or when other dusts are inhaled, or in the i-cure of infection. It is probable that the main source of the diagnostic difliitics is caused by the emphysema which nmfllcs the physical signs and is responuh emphysema, such as restriction of costal and. diaphragmatic movement, diininule in great part for the absence of symptoms. It may blot out, even on X-ray, silicotic lesions of fine size. Examples of such difficulties in diagnosis as cncounid by us arc the following;
( ase /--Mr. T. A forty-five year edd man entered the New York hospital inpluiiiing of mild cough and expectoration of four months' duration. He appeared itcly ill, his fever was 103 degrees and respiration 28. Rales were elicited over
upper half of both sides ol the chest. Examination of his eye grounds rescaled itcral retinal tubciclcs: his sputum contained numerous acid-fast organisms. ie X-ray rovtabd fine mottled shadows distributed throughout both lung fields d a small cavity at the left apex. A diagnosis of miliary tuberculosis was made, never, alter one weeks' stay in the hospital, bis lempcinliirr and pulse returned normal and during the following itionlh be gained IS pounds. I he signs in bis st now l-icame confined to the left apex. In view of liis_iiuusu.il progress the ignusjs of miliary tuberculosis was doubted. Jlis occupational history revealed it up until three years before entrance to the hospital lie had worked for 211 ars pulidiiug leather on a sandpaper wheel. There were numerous machines ill work room and no precautions were observed to clear the very dusty air. % sputum was c'nmincd through the kindness of l)r. llurke of Kav brook, N. Y. 10 found it laden with numerous doubly refraelile silica particles, lie expressed opinion that this was cousi-tciit with silicosis for he bail found such numerous 11 tides only ill cases of silicosis. The patient subsequently died of a tuberculous uingitis. Retinal tubercles were demonstrated on microscopic section. The hologist's report was miliary tulierciilnsis. Ashing of the lung showed increased n;i content, coi.-istcnt with undue exposure to dust (more than 2 iiigm. silica per m dried tissue).
Cate II--Mr. /?., aged 5-4. entered the New York hospital complaining of iiopf.xcs. dyspnea and chest pain. On phi deal examination there were rales I dullness over the upper third of the right chest anteriorly. He ran a low dc fever but was robust and felt quite well. The chest X-ray disclosed enlarged mi shadows, particularly on the right, and diffuse mottled discrete shadows
Occupalioual Diseases
131 '
throughout both lung fields with a circumscribed density near the right apex. He 1 gave a history of having worked for twenty-four years as a cutter and sizer of I
asbestos-containing paper box boards. The rooms were in a continuous cloud
of dust. Examination of the dust revealed 5 per cent silica content. The hemoptysis, we felt, was to be explained on the basis of infection or neoplasm, but we did not
know whether we were dealing with one of those processes alone or an associated
silicosis or asbestosis. A small nodule in the neck was subsequently removed and
showed carcinoma. We arc inclined lo believe that this does not explain the whole
process, as the man is still alive and certainly, from the X-ray standpoint, we cannot
say that there is no silicosis.
'
!
Cure III--,1/r. C. A dish-washer, aged 4f>, entered Ilcllcvtic hospital because
of cough and expectoration, associated with dyspnea. There was some dullness and rales at the right base posteriorly. Chest X-ray revealed a homogeneous shadow at the right base. His sputum contained no tubercle bacilli and lipiodol study
revealed no abnormalities, l'.rouchoscopic examination disclosed a bleeding mass in
right main bronchus. Symptoms ami .disease progressed during the following four years. Discrete mottled shadows first appeared in the upper right lung ficid and the shadow at the right base cleared somewhat. Three years later extensive ab normal shadows were present throughout both lung fields, 'particularly on the right. Diagnosis of chronic pemnnonia of unknown etiology was made. At n<> lime was
a diagnosis of silicosis entertained, because as far as could be determined he had no history of exposure. Furthermore if there were silicosis it behaved verv alypically having the lesion confined practically to the right base at the beginning and then spreading to the left lung. Autopsy however, revealed a typical silicons
associated with a small degree of tuberculosis. A picture of the lung showed
how much more extensive the silicotic process was in the right lung. There was
stenosis of the right middle lobe bronchus with bronchiectasis in this lobe. C hronic
infection in the lung field probably accounted for the unusual localization. This
case illustrates hove necessary it is to have the history of dust exposure for without it here vvc arc tillable to even suggest a diagnosis.
Case IF--Mr. C., aged 45, complained ol rough and dyspnea with slight expec toration and gave a history ol having worked for ninny years repairing tires, using
talc powder. It 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 apices and a few tubercle bacilli were found in the sputum.
Discrete and stringy shadows were disseminated throughout both lung fields. W'e
know from thp positive sputum that tuberculosis is present. The patient has. however, been well for a period of two years. The doubtful historv of exposure
together with the numerous discrete nodular shadows in his lung, which arc Coii-
sistuit with silicosis, makes this patient a problem. Is this tuberculosis alone or
is tills tuberculosis with silicosis? The patient is still living a vear later and
working.
''
(Vur/imim. Cases such ns these are exceptional. Iml their existence inn-1 always he home in mind. H occupational history is inadequate and X-rav. clinical and
lalmratory studies prove misleading, the diagnosis may present great dilliculty
However, a comprehensive study of all jmssihlc data nsiiallv clears up the problem
with reasonable certainty.
,
'
.WIOURS'MF.XT
Safety liiptifuicul
Safety Equipment
WEDNESDAY AFTERNOON SESSION
October 16, 1935
The session was called to order by Chairman, Irwin W. Millard, president. Industrial Gloves Corporation, Danville, 111. Chairman -Millard mentioned some ot the problems of providing adequate safety equipment for industry.
Respiratory Protective Devices
(An interpretation of the U. S. Bureau of Mines, Schedule 21)
By CARLTON E. BROWN, Chemist, and
WILLIAM P. YANT, Supervising Chemist
Gas Section, Pittsburgh Experiment Station, Pittsburgh, Pa.
The respiratory protective devices of industrial hygienic importance arc those designed to protect against the inhalation of harmful solid, gaseous, or liquid atmos
pheric contaminants, or the inhalation of air deficient in oxygen. The devices in common use arc the mechanical filter respirator (commonly re
ferral to as respirator) for protection against the inhalation of dusts. smukcS. fumes, and mists or what may he referred to collectively as atmospheric particulate matter; gas masks for protection against the inhalation of gases anil vapors; oxygen breath ing apparatus, hose masks, and air-line respirators for protection against (lie inhalation of any atmosphere provided it docs not contain harmful constituent which can he absorbed readily through the skin: and the abrasive blasting helmet or hood for pro tection against the inhalation of and the impact and abrasion from the atmospheric particulate matter generated in sand blasting or abrasive blasting with steel shot.
These devices arc designed to furnish protection either by making the wearer's inspired air safe to breathe or lie supplying the wearer with safe air from a supply
which he carries or from outside the contaminated zone. The wearer of the first or air-purifying type, on inspiration draws air from his
immediate surroundings through the device which cither removes the contaminant, usually In- chemical or mechanical filtration, or converts it into a harmless substance. This type, of course, offers no protection against atmospheres deficient in uxygent as it does not add oxygen to the air.
There arc two types of respiratory protective devices of the second type designed to supply the wearer with safe air. In one. the wearer receives his air supply from a
cylinder of compressed oxygen, liquid oxygen, liquid air. or from a chemical which yields oxygen upon decomposition. This air supply is part of the self-contained unit, all of which is carried hv the wearer. In the other type a hose, attached to a face piece. is connected to a compressor or blower whose intake is located in safe air. Air is forced through the hose to the wearer.
Xntc: Published by permission of Director, lb S. bureau of Mines. (Xot subject to copy
right.)
.
133
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Fwrwwiw jt. j
I rwntty-fourth Annual Safety Congress--National Safety Council
'Is from manufacturers and consumers that this bureau test and approve such t 5. >,
'-.hcdulc 21 follows the general plan of the other bureau approval schedules for *ial respirators; the pre-test and post-test requirements arc quite similar, and , .ucral principles of the test requirements arc the same. The primary purpose of ^ .iper is to explain the reasons for the various test requirements.
Pre-Test Requirements
I lie pre-test requirements of Schedule 21 require that the manufacturer submit nation, drawings, :md samples of the device to he tested. The device must he* . iclcly developed and ready for release to the public, and the device when IcMcil ic mamif.ictuicr or his agent must have passed tests of the nature described thcilulc 21. The reasons for the third requirement arc: (1) To assure the .hi that the manufacturer is prepared to control the filtering characteristics of c-pirat*`r; (2^ to eliminate any question of competition with private consulting , ii s in developing respirators; (3) to furnish cvifleiicc that the respirator really adv for release to public market; and (4) to save the manufacturer's and the .aids lime. After the manufacturer has complied with all the above pre-test .cincnls he must submit a fee for the examination ami test of his device, fee is turned into the miscellaneous funds of the U. S. treasury and none of . Money reverts to the Bureau of Mines.
Test Requirements
t
In developing the tests for mechanical filler respirators consideration was given : to the general requirements for a safe and suitable device. These requirements
similar for all types of industrial respirators. The respirator must (1) give
quale protection. _ (2) he reasonably comfortable and physically convenient to r. and (3) provide an acceptable service life.
Adequate protection implies that the mechanical filler respirator when properly oi.ooed and worn must prevent ihc veearcr from breathing enough particulate
or to cause a harmful physiological response under the conditions of occupational -lire for which it is designed to he used.
I'omfort and physical convenience factors are equal in importance to adequate |. clion. l-.veu though aware of the ultimate serious effect which will he produced
r proloncrd daily exposure, workmen are inclined to he diffident and unwilling dor much daily inconvenience and discomfort from the respirator.
I ncmnhrance and discomfort also increase fatigue, cause distraction, and in -al handicap the wearer's ability to lake care of himself, thus increasing the 'bilily of accident. Important specific items include the weight of the respirator,
arriage on the face or heed, effect on vision, heating of the area of the skin r the facepiece, inability to expectorate, difficulty in talking, and resistance to
idling. The importance of comfort and physical convenience cannot he over
.'u.ltcil.
(
I lie serene life involves elements of practicability in the wealing and maintenance die device, and indirectly the safi ly. This type of rrspirntur is primaiity not an igvney device, lint a pat t of the workman's equipment for doing his regular job l.v. If the service life is short, the bother of ebim.giiig of tiller eli inents will
irllcctrd ill the woikmnn's altitude toward good niaiiilenanee ami usr.
All iiicrliiinirid filter respirators are sulijci led to certain inspei lions and tests they must fulfill certain requirements. The general design and eoiwli urlion, innlierly as to facial fit, fnedom from iri dating facial contacts, weight, effect
vision and (he wearing of goggles, and ease of changing filler elements, anil
mined. 'Ihc materials arc examined to determine if they are obviously suited
the purpose for which they arc designed. Rubber parts which come in contact q the skin must not contain any skin-irritating constituent. , ,
.Resistance to Air Flow Requirements
Ihc requirements for resistance to air flow are the same for all approved mc-n'cal filter respirators. At no time during or after (he filter efficacy testing period -t the resistance to air being drawn through the device at the rate of 85 liters
Safely Equipment
137
(3 cubic feet) per minute exceed 50 millimeters (1.97 inches) of water column"
height or the resistance to air being blown through the device at the same rate
of (low c.xrceH 25 millimeters of water column height. An air flow of 85 liter
per minute is approximately equivalent to the respiratory rale oj a man doing hrav,,
work. The amount of particulate matter pulled to the deuce during the fillc.
efliracy tests is roughly equivalent to the amount that would be pulled to llic biter
hv a worker wearing the mechanical filler respirator in a moderately concentrated
su-peiision of the particulate mailer during an R-hour period. Thus resistance to air llow of an approved mechanical filter respirator should not become excessive when worn
for an R-liour period in most suspensions of ntmo-q hcric particulate matter en
countered in industry. The mamifactuier is rem 'id to give instructions on cleaning
or changing the filter elements when the le-islan.
.nr ilovv noticeably menascs.
Direct Leakage and Man Test
All mechanical filter respirators arc subjected to a diml leakage and man test to determine facial fit, whether there is any direct leakage of miMicied air. and to obtain information on the comfort ol the device. 'I luce of the. mechanical filter respirators arc worn for 30 minutes by 3 men with dillireut facial icnlnrcs m an atmosphere containing a heavy suspension of hituminoiis-roal dost. At the i ud of the period the respirators arc removed and that part of the fare covered hv thd facepiece is examined for evidence of any leak under the edge of the facepiece. Sticks a millimeter thick were wedged under the edges of the facepieces worn by 'objects A and C to cause the leak's. The location and approximate magnitude of the leaks arc slmvvn by the black streaks on that pari of the face covered by the edges if (lie facepieces. The nasal passages and sputum of tbc subjects are also examined before
and after tbe tests.
Filtering-Efficacy Tests
In the development of the filtering-efficacy tests, particular allenu'nn was given
to the physical properties, especially particle size, of Ihc significant kinds of atmos
pheric particulate matter encountered in industry. Previous studies of filtering
mate rials had shown that, ill general, filtering vfbenry decreases with a decrease m
particle size.
>,
It was decided that most of the significant iudueti iully generated atmospheric
particulate matter could he classified into the following three groups in .accorikuirc
with method of generation, physical state, and particle size;
1. Mechanically venerated dusts resulting from the disintegration of a Solid,
such as the dint clouds produced in Ihc vaiimis processes of mining, quarrying and
tunneling and the grinding, crushing, and general processing of solid materials.
This type of atmospheric particulate matter is referred to as Type A atmospheric
particulate matter anil mechanical filter respirators designed to furnish protection
against these suspensions are referred to as Type A mechanical filter respirators.
" 2. Fumes of various metals (usually their chemical compounds, as oxides or
cm Inmates) surli as lead, mercury (except mercury vapor) manganese, magnesium,
aliiinimiin, antimony, arsenic, copper, chromium, iron, cadmium, and zinc ri suiting
fr.>ni sublimation or the eoiuliiisation ol their vapor, or from the rlu inic.il ructions
between their vapor and gases. This type ol almosphedc particulate inaller is re
bind to as Type I! atmospheric particulate matter and iuecb.iiiir.il filler ic'piralors
It signed to furnish protection against these suspensions arc referred to as "type IS
mechanical fillrr respirators.
3. Mists as produced Ivy spray-mating with paint ami vitreous enamels. chromic
add mist as produced in chromium plating, and other mists ol materials whose
liquid vehicle does not produce harmful gases ur vapors, 'ibis type of atmospheric
p.uticukitc matter is referred to as Type C .atmospheric particulate mallei and
qiechanical filter respirators designed In Inrnisb protection against these suspensions
arc referred to as Type C mechanical filler respirators.
The mechanically generated dusts and fumes consist of solid particles while the
mists consist of liquid or liquid-coated solid particles. The particle size of me
chanically generated dusts extends over a wide ranee, in some cases, from pui tides
visible to (lie naked eye probably dow n to molecular dimensions. 3 lie range in
.pm tide size of fumes is much smaller. The upper limit is in the lower microscopic
M8 Twenty-fourth Annual Safety Congress--National Safety Council
. npe (about O.S micron), while the lower limit probably approaches molecular
itcnsions. The particles of some fumes, particularly zinc ami magnesium, readily
n and form large flocklike clusters. The effect is least pronounced in the case
lead. Mist particles arc spherical and probably more uniform in particle size than
sc of dusts and fumes.
''
Suspensions of each of the types of industrially-generated atmospheric particle alter were selected for use in lire filtering-efficacy tests. These suspensions were iiosen on the basis of their industrial hygienic significance and their physical roperlies. such as particle-size distribution and tendency to aggregate, which have i appreciable effect on filtration. It was desired to test the mechanical filler
piralors against the most common or widespread harmful suspensions of each
ye: the lest suspensions to have physical properties, such as particle size and eregation tendency, which would render them as difficult to remove by filtration any other suspension of the same type. The test suspensions selected arc:
(a) lor testing Type A mechanical filler respirators or those designed to -nisli protection .igainst mechanically generated dusts a suspension generated from ry fine (99+ per cent through 325 standard mesh sieve) silica dust consisting of ' r ptr cent free silica (SiOi) is used. '1 lie suspension is generated in such a way vat all particles larger than about 3 microns arc removed before the suspension tirs the test chamber. The particle-size distribution of the test suspension must ! exceed a geometric mean of 0.6 micron and a standard geometric deviation of -'0. T he particle-size determination is made by collecting samples of the suspension
the Owens jet dust counter and determining the particle size distribution by a i.roprojictinn method developed by the Ifmcnu of Mines.*
(h) l or testing Type ff mechanical filter respirators nr those designed to irnisli protection against fumes, a lead oxide fume generated by the combustion of itural gas containing lead tetraethyl vapor is used. The particles of this fume arc slrcmcly small and have about the least tendency to aggregate of any fume, hence icy are very difficult to remove from the air by mechanical filtration. A suspension
magnesium'oxide is also used to determine the effect of a fume, whose particles lib. aggregate in large clusters, on the resistance to air flow of the filter of the vice.
(c) For testing Type C mechanical filter respirators or those designed to ruish protection against mists, three different suspensions arc used. Chromic id mist generated by electrolyzing an aipieotis solution of chromic acid, as is done industrial chromium plating; lead paint mist generated by spiay-coaling with lead ini; and a water mist carrying silica dust generated by spraying a 2 per cent nous suspension of silica dust are used. The water-mist carrying silica dust is d to simulate the mists generated in sprav-eoating with vitreous enamels. '
The < nmiftnlioii of tin* pnihTnlatc matter in (lie IrM suspensions was chosen rcprrstnl more nr less (lit* h'nduT concentrations found in bullish y. Shut (lie
u< < tilt nf ion of mechanically generated dust found in industry varies over such
*lc limits it was (United to test Type A mechanical (liter respirators against two 1 ic itli.ilit'iisj one ( represent tin* inure nr less average dusty industrial roudiiis, and 11 <* oilier to represent very dusty conditions.
'J lie emnpli te mechanical filler respirator is tested mi a meelianieal testing paralns. J lie test suspension is pulled through the device at flic rate of 32 liters ! 13 cubic feet) per minulr. mnlbmons flmv. TJir volume of air pnllrd through mechanical filter respirator is 10 cubic inclcis in all cases except in some is against particular Kinds of suspensions ns mechanically generated lend dusts d in the high-silica dusl-cnurciifratinu lest and the magnesium oxide test whose rimnry object is 1o determine the increase in icsistanrc to air flow of the filter illt the amount of particulate matter retained. Ten cubic meters is approximately juivnlent to (be volume of air breathed by a worker in 8 hours, 'flic samples of irticulnlc mailer for concentration determinations arc precipitated electrically m the air of the test suspension both before and after it has passed through mechanical filter respirator. The samples arc collected in containers which i he weighed readily on an analytical balance. For reasons of convenience, speed,
C\ . attj Ynuf, \V. I*. The - Mici(-prjcclor for Determining Particle Sire
11ihiit( ami Number Concentration *f Ahmiq-hcnc J)uhs. Ik S. Jiuie.iu of Mines Jtegurt
InvcstieMions 3287, 1935.
.
Safety Equipment
: 13.9
nmj accuracy the samples of silica dust arc ipiantilalcd by weight rather than Hy
count. Samples of the oilier particulate matter arc ipiaiititntrd chemically.
The requirements as to the ammint of particulate matter that the mechanical
fdter respirators must remove from the air pulled through them is based on the best
available information on the concentration of the particulate matter that is safe ur
breathe. These requirements arc subject to dinner with the at cumulation of h.inwl-
edpc mi the physiological clTects of industrially generated atmospheric particulate
mailer. In other words, the filterung-clbcacy riquircuunt is that the air inhaled by
the wearer of such a device must lie safe to breathe, and not that the device ha\c any
pai tit ular percentage filtering efficiency.
Mechanical filter respirators arc not appimcd fi*r an> substance more hart dul
than the particulate matter in the test suspension against which they are tc<ird.
Thus Type A respirator? arc not approved for any substance more harmful than
free silica (SiO:) dust. However, Schedule 21 provides for testing and approving
mechanical filter respirators against any hind of indnMrinlly generated alum-phene
partieulatc matter. For example. Type A mechanical filter respiraPrs are not approved for protection against poisoning hy breathing dusts whose main barmful
constituents arc metals or their compounds. 1 lowc\ci\ two mechanical filter respira
tors have been submitted and approved for protection agaim-t the inhalation of
mechanical generated lead dusts.
.
Table 1 summarizes the details of the filicrmg-cfhcary tests and lists the me
chanical filter respirators which have been approved to date. (Pages 140-141.)
Post-Test Requirements
The manufacturer of an approved mechanical fdter respirator is required to mark his device with the name of Ids company, the name letter, or number by which
the type is designated for trade purposes, and the approval number as-ie <l to the device hy the lhircau of Mines; and the filler unit must he marked with the approval
number and with the type or kind of atmospheric particulate matter for which it
is approved.
..
The me<hanical filter respirator and replaremml idler units must he prmidid
with substantial and durable containers, lupus of the approval labels issued to the
manufacturer hy the Purcau of Mines must he attached' to these containers. I be approval label gives the approval number, shows to whom the approval is i: mt <1.
stales what the device is and is not approved for, and cautions the wearer to I llnw the manufacturer's instructions for the use and care >f the device.
The following is a sample of the required instructions, furnished by the uium-
facturer. These instructions arc similar for all of the approved mechanical : her
respirators.
Instructions for Use of Mechanical Filter Respirator
1. Respirators will not protect unless placed on the face piopcrly eaili lime they are worn. Carelessness in face-lit naans danut toils leakage. In general, a better fit is obi.lined if the mask is vvoin imt too high on the no*-r.
2. To fit the Mspirator to the face Imld the respiratorc\li.m-.t valve pointing downward, by the metal screw connection with either hand, and hold the luadsttnp with the other hand. IMacc the fare piece against the face and hold it in phuc while pulling the hcadstrap over the bead and below the ears. Tlun adjust the facepiece until a firm snug fit is obtained. The hcadstrap tnav be adjusted while the respirator is in place hy holding the metal slide between the thumb and forefinger of one hand and pulling on the proper strap with the other hand.
3. To instruct the wearer in the proper adjustment of thehead<lrap*and position of the respirator on the face a cardlmaid disc is enclosed. To use this disc unscrew the filler hag. place the disc against the felt washer in the metal connection on the felt hag. assemble the respirator, and put it on. T he wcaier should ` not he able to breathe through the respirator or feel any inward leak tgc of air under the edges of the facepiece.
The presence or absence of dust streaks on the face inside the line of fit of the facepiece after wearing the respirator in a dusty atmosphere can also he used to tell whether a proper fit was obtained.
4. The recommended procedure for cleaning the filter hag is to insert IoomIv the nozzle of a high-pressure air hose into the hag opening and to blow several
HO Twenty-fourth Annual Safety Congress--National Safety Council .
\
TABLE 1. DETAILS OF FILTERING EFFICACY TESTS AND LIST
----------- -----------
- -
-
-- .......... .... 'i
Kind of mechanical
niter-type icH'ir.Kor
Industrially generated atmospheric particu* l.ite matter against which the device is
designed to furnish protection
Test suspensions used
Jv|*eA
Mechanically generated dusts resulting
principally hour the distintegiation of a snlnl, such as the dust clouds produced in mining. (|uair\ing and tunneling, and the industrial operations of pi hiding, crushing, and processing of minerals
Air-suspended ground Hint, which consists ol 99+ percent free silica (Sil>). Over 99 percent ol the dust passes through J25* mesh standard sieve
.,
I'speU '
T- i-eC
l
Kumes of saiious metals (usually their ibemical compounds, as oxides or carbon* ales) such as lead, mercury (except met* curv vajor), manganese, copper, chromium, iron, cadmium, zinc, magnesium, altimi* num. antimony, and arsenic resulting Irom sublimation or condensation of their vanor,
.or fiom chemical reactions between their tapor and gase*
Mim is |.r"dm.t.| hv s-piay rnaiiiiB with pamt and viucm^ enamels, thiomic acid mint as produced in rhiomiunt plating, and *'ther hums of materials whose liquid ve* hide does not produce hannlnl gases or
vapors
(a) head oxide fume produced by the de*
composition and combustion of lead
tetraethyl
`
(U1 ovule tunic, freshly prodnred by burning magnesium ribbon
^ t'hinmie arid mist produced by electro* Iv/iug an ;npitous solution (200 500 grams of chiomic acid per liter) ol
chromic acid
itally
ied lead
Mechanically generated dnMs who.se mam haimfnl constituent is had. such a< had dusts generated in m.inufacliiiing storage batteries; iii.uncting; pnttt'v making; iol>-
ber compounding; sandpapciing and chip*
ping painted surfaces; paintmaking; pre* paring l/iho;transfers; and mining, milling and pn<c-sing lead ores
(b) I-cad^ paint mist produced by spraying
a paint having the following composi
tion: white lead (paste having appto\i*
mately '.'I peiccnt white lead and 9
pcicent liiiM-cd nil hv weight), 100
grams', linseed oil, SO cubic centime*
tors: and steam-distilled turpentine, 25
, cubic centimctcis
4
ft) Mist produced by spraying a 2 pricml
aqueous >uspciisi>>n of ginuml Hint, air*
flouted <9-b peircni .through 32> stand*
aid mesh sieve). The ground flint con*
sists of 99+ pcicent her silica (SiO.-l.
Mixtuie u'td in making negative plates ol
had storage battciics. Contains 72 pcicent
litharge, J'liO; 2a percent red lead. J`b.,0;
and 3 percent lampblack
* One milligram = 0.0154 grain, 'One culm* meter :z .35.315 cubic feel.
* kale ol sampling = 32 liters (I.U cubic feel) per minute. - One milligram of thi silica hi't contains appioximatrlv 3M0 million p.otiile* as deter* *ied by the impingcr method as desnibed by the U. S. Public Health Service, lienee, 1 'tikram per cubic meter of this diis( is approximately equivalent to 8.5 millions of paiticles -.lie foot,
* be*- previous listing of company for complete addiess.
Safety Equipment
1
OF APPROVED MECHANICAL FILTER-TYPE RESPIRATORS
Concentration of test
suspension, milligiams4
per cubic, meter* ol air (a) ?0 I0#
do 5 :J
IS 5 ol lead
Volume of
test suspension pulled
through the
device, cubic meters*
Maximum amount of particulate
matter permitted to pax*
X.rnir and manufacturer of mrih
through the device
ical bher-tjpe re-pnaims appro
to date, September 2\ I9J4
Milligrams
Milligrams
per cubic meter of air
2.M 4 mg. for ,inv 1 of 3 devices, or an
average of 3 mg. for each of the 5 devices *
1.0
M S A. Cnml.i Respirator. Appro No. 2101, i-Miol to Mine Safety pliant es Co.
Willson Pap Respirator No. 3 Approval No. 2102, issued to W i son PriKluets, Inc.
9.98 .
12 mg. for any 1
l.fr*
Willson 11.ig Kespir: tnr No. l
of 3 devices, or
Approx ed No. 2b,J. i* n<J to Wi
an average of 10
pr.nlucts, Inc.*
mg. for each of
9.98
1.5
0.15
Vulmosau M-15 1`omh Type lib Kc*pirntor. Approval 2 i. 2101, i
sued to J'uhno'-.iu Sabir Equipmci C'orp.
Itiever Ke*i'ii air. Approx.il N 2105. is'-ued t* Stand.ud Sa:e Hquipmcni Co. *
Willson l'ag 1'c'pimtnrfNo. 4 Aj
i-ioxal No. 2!0. is'-ued* to Wills#
I'lodiict.s, Inc,*
,
100 25 15 - 5 of t
chromic acid
HO-f-OOrd lead
2 9.9R
1
9.98
1.5
_ 0.1
1i
M.S.A. Comfo Respirator. Approi. No. 2101, t<iicl to Mine Sain Appliance* Co*
0.15 M.S.A L'miifn Respirator not .*, proved for lead com.lining mnli.
Id 5* of mIu a dust
15 5 nl lead
9 93 5 2.88 o. u
n s* M.S.A. Comb* UcvpitMm-. A|>pior.i No. 2101. isMicd to Mine Safety Ap pliances Co.*
0.15 MSA. Combi kcpiia|Mi` with spe ci.il fibers (of lead dil-t. \ppio\.. No. 2107. i-'-itcd to Mine S.dclv (< pli.mccs Co.*
Willson II..g kcspii.itof ,V.i. Iri| Approval No. ?inx. iMn-d to Will son Products, Inc.*
142 Twenty-fourth .innital Safety (. angrrss--Mutionn! Safety Council
sliort blasts of nir into the hair. This procedure removes from the bag dust and
jjnt which clogs the pores of the filter and makes breathing difficult. The proper
time for cleaning the hag is when the wearer experiences discomfort in breathing.
When compressed air is not available some dust may be removed by tapping the bag lightly and brushing the outside of the bag.
5. To prevent irritation of the skin and for .general sanitarv purposes the
respirator should be cleaned after each day's use. The rubber and metal parts
may be. cleaned with soap and water, and for general sterilization thev may be
dipped in a 3 per cent solution of carbolic acid, a 2 per cent solution of lysol. or
a 70 tier cent solution of denatured alcohol, then rinsc<| with water, assembled,
and hung up by the loop in the felt bag to dry. The tiller bag and hcadstrap always
must be removed before the respirator is washed or sterilized.
6. While not in use the respirator should he kept in a dust-free place, prefer ably in the original container.
The manufacturer is renuired to maintain the quality of his product and to see
that each mechanical fdter respirator in all its parts is constructed according to the
drawings or records that have been accepted bv the P.urcan for this device and that
are in the Bureau's files. Mechanical filter respirators that exhibit changes in de-
. sign or include any parts that have not been approved are not permissible respirators
and must not hear the Bureau's approval label. Schedule 21 provides ior the manu
facturer to apply for an extension of approval on any change in the mechanical
filter respirator which does not affect the filtering characteristics of the filter.
Changes in the filter require the application for a new approval. The Bureau obtains information on the maintenance of design and quality of
approved mechanical filter respirators by testing samples of the devices obtained
on tbc open market. Tlic Bureau reserves tlic right to rescind for cause any ap
proval issued.
'
A Safety Style Show
By E. J. SMITH
Safety and Health Director, Western Electric Company Hawthorne Works, Chicago
For the purpose of assisting our foremen in the selection of the proper safety
equipment we have standard specifications and every foreman has a copy. In it he
will find the protective equipment required for any class of work.
Moldcrs. cupola tenders, furnace tenders and helpers in foundry and forge
are equipped with heavy duty metal or composition cup goggles with hardened
lenses. The lenses in the furnace tender's goggles arc of a forge and furnace shade.
Electric furnace tenders, however, wear a welder's goggle, described later. When a
goggle is equipped with clear lenses, it is used for such operations as breaking detec
tive castings, cleaning castings with compressed air. grinding castings to remove
gates or fins, pounding on castings to remove sand cores, pouring molten metal into
mohls with hand or bull ladles, removing gates or fins inmi castings with air chisels,
or hand chisels and hammers, and working' in vicinity of chipping hammers.
Leggings arc of the non-lacing, non-buckling and snap buttoning type held in
place by hidden steel springs similar to the old bicycle pants guard. They will come
off instantly from a tug at any point. There arc no gadgets to contuse you or those
who arc trying to help you in an emergency. Just one simple thing to remember--
grab anywhere and pull.
Men wear safety hats when chipping slag out of cupolas. Our construction
crews of masons, carpenters, millwrights, and so on. wear them whenever they are
engaged in work where there is the slightest chance of objects falling from overhead.
Our employees wear "Congress" safety shoes for their protection in addition to
the leggings. '
'
We use a leather steel faced glove when charging a cupola or handling pig iron.
Full leather palm gloves with band top arc used in chipping casting fins, load
ing and unloading tumbling barrels, and removing castings from sand.
For the protection of health, workers in the brass foundry arc provided with
overalls and undershirts with full length sleeves. This is in accordance with Illinois
Safety Section, A A R--Steam Railroad Section, N 6' C
Safety Section, AAR--Steam Railroad Section, NSC
Officers 1934-1935
General Chairman--T. H. Carrow, Pennsylvania Railroad, Philadelphia. First ['ice Chairman--W. H. Failing, Central Railroad Company of New Jersey
Reading Company, Philadelphia.
Second Vice Chairman--C. P. Larson, Missouri Pacific Lines, St. Louis.
Members of the Committee of Direction: Eastern Territory--II. R. Cole, Erie Railroad, Cleveland, Ohio; Charles E. Hill, New York Central Lines, New York City.
IVestem Territory--L. F. SirF.on, Chicago, Rock Island and Pacific Railway, Chicago.
Southern Territory--D. H. Beatty, Southern Railway, Washington, D. C. Secretary--J. C. Cavisto.v, Association of American Railroads, New York City.
Officers Elected for 1935-1936
General Chairman--C. F. Larson, Missouri Pacific Lines, St. Louis, Mo. First Vice Chairman--E. A. Meyer, Chicago, Milwaukee, St. Paul and Pacific
Railroad, Chicago. Second Vice Chairman--E. G. Evans. Louisville and Nashville Railroad, Louisville, il[embers of Committee <>/ Direction:
Eastern Territory--A. O. Beck, Canadian National Railways, Montreal; H. A. Rowe, Lackawanna and Western Railroad, New York City.
IVestem Territory--F. W. CuRTts, Denver and Rio Grande Western Railroad, Denver.
Southern Territory--L. G. Bf.ntlf.y, Chesapeake and Ohio Railway, Richmond. Va.
Secretory--J. C. Caviston, Association of American Railroads, New York City.
A complete report oj these sessions is published by the American Railway Associ ation in a booklet entitled, "I'rocccdinns of the Fifteenth Annual Medina of the Safely Section, Louisville, Ky.. Oct. 15 to 17. 1035." Copies of the booklet are available from the Association of American Railroads, N. V, C. The follotuintj is a condensed record.
TUESDAY MORNING SESSION
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
'
Council
at all times, .list there is
hides more ivty rules or ing the case, in trouble, lion recently, years ago. >. to properly lerstand your at will never >, because he pressions im'lish interests vinoved from lie early days
of education
itended doing ructions, but
iorethought.
widely dis un to glance
of habit that accidents, or influence ol
nforce those processes for
roup of men
ne Railroad
mess Associ-
Id down to tain of our
danger were ;gers killed.
to be upon XFORCED. . stray upon i.istanter and surplus and
: respect is Mates 50,025 ' 'nited States
two months. < 'da. In the
red on the nada."
Safety Section, A A !(--Steam Railroad Section, N S C
463
From the following it will he gleaned the situation on our railroads has im proved perceptibly with regard to the trespassing evil, particularly when considera tion is given to the fact that our population has increased and operation accelerated.
Years
' Killed
1901 to 1910........................................50,025
1925 to 1934....................................... 24,951
.
Injured 53.427 30,200
Totals 103,452 55,151
Decrease................................. 25.074 (50%)
23,227 (4395.)
48,301 (407)
Seeking an answer to these decreases, the following comes as the result of investigations:
(a)--Safety education in the schools, promoted to a great extent through activi ties of the railroad safety departments.
(b)--Protective measures adopted by railroad police departments. (c)--Introduction of other modes of transportation brought about by improved
highways and the practice of hitch-hiking.
Persons entering upon property occupied by another, in the absence of any contractural relationship between them, necessarily come under one of three distinct classifications or categories. (1) Invitees; (2) Licensees: (3) Trespassers; and the duty the occupier owes to any such person is graduated in strict accordance with the category to which such person belongs.
Toward trespassers the occupier owes no duty. The trespasser goes on the premises at his own risk and the occupier is liable only for acts done with the deliberate intention of doing harm to the trespasser or with reckless disregard of the presence of the trespasser.
The very nature of our business and the vast amount of territory covered by tracks, terminals, yards and stations renders the problem of trespassing unusually difficult. The impossibility of policing all these properties every hour of the day and night, is apparent. The best we can hope to do in that direction is to extend the services of our special officers, guards ami watchmen as far as they will go. and rely upon these men to inculcate the spirit of watchfulness into all officers and employees so that trespassing will be held to a minimum.
Trespassing by our better class of citizens who sometimes do it unwittingly is capable of being controlled by active interest on the part of our agents or representa
tives. Trespassing by school children can be partially cured by appealing to parents and
school authorities. This plan lias been tried out on many railroads'-with success.
As to what might be termed "general trespassing'' on railroad premises, it is conceded that an appeal through the press, and hy continually reminding the public that hazards exist wherever there arc moving engines and cars, is by far the
best method known for correcting this evil. The use of bulletins and posters should commend themselves to all railroads
interested in breaking up the practice oi trespassing.
TUESDAY AFTERNOON SESSION October 15, 1935
Value of Accident Prevention
By FRANK WENTER, JR.
.
General Claims Agent, Chicago & North Western Railroad
In the early days accident prevention activities on the American Railroads were confined to the safe delivery of the trains over the road, and these activities in time were consolidated in our present Cook of Rules. This apparently was the only safety
46S T:ccnly-J ouvth . hiuntil Safety Cninjress--National Safety Council
portaut rules tint .arc not being enforced, .and I want to quote Mr. W. J. Patterson, director. Eurc.au of Safety, Interstate Commerce Commission, in what he said last year--"An operating officer .assumes a grave responsibility if. in his desire to ex pedite the movement of traffic, he permits violations of rules to go uncorrcctcd."
WEDNESDAY MORNING SESSION October 16, 1935^
. Address
By JAMES J. DONOHUE
Claims Attorney, Louisville & Nashville Railroad, Louisville, Ky.
More than three decades ago. President Thco. Roosevelt, Gifford Pinchot. of
Pennsylvania, his brother Amos, and others began to preach the preservation of the
natural resources of our country, and since then we have heard much in regard
to the conservation of coal, timber, iron, oil, copper, and the precious metals. But
to me it has always seemed strange that it was not until 19P>* that any organized,
concerted effort was made to conserve the most precious things in -the world--the
lives and limbs of our men. women and children. In that year the National Safety
Council was bom. and there was then begun and intensively carried out a well-
organized campaign to instill into the minds and the hearts oi the people of America
the principles oi safety--safety not only on our railroads and in our manufacturing
plant-, hut in the homes, on the streets, in our schools, and at other places where
accidents involving personal injuries arc likely to happen. To my mind, the Na
tional Safety Council, after the American Red Cross, is the greatest humanitarian
agency in this country.
In no other industry has the doctrine of "Conservation of Men" been more
intensively and intelligently applied than in the railroad world. In the old days,
casualties were considered inevitable: it was thought that they were all in a day's
work and were bound to happen, no matter how well regulated or efficiently operated
the particular railroad might lie. IIow utterly fallacious this theory was, you are
able to demonstrate hv pointing out the constructive work your organization has
flnnc in the oast twenfv-tive years.
_
It is now well recognized that "railroading" is not extra-hazardous when con
ducted by prudent, careful men, but that when railroad operations arc in the hands
of the reckless, the dare-devil, and the chance-taker, it is hazardous in the extreme.
Railroad managements, now more than ever before, exercise care to furnish em
ployees with tools that arc safe and in good condition, and with a safe place in which
to work, safeguarding that place in every way practicable. In addition, railroad
supervisory officials, safety committees, and employees acting in co-operation with
such committees, are endeavoring, in season and out oi season, to bring safety lessons
home to the individual employee, through the written and the spoken word and
through the medium oi apt posters displayed in conspicuous places about shop and yard.
The very nature oi my calling makes me prefer to talk to you in dollars and
cents. In 1947. latal and nonfatal eases cost the Louisville & Nashville Railroad
Company $1.001.511.Sfi. while in 1934 the cost was only 5415.055.88. These figures
tell their own story, looked at through the glasses oi a humanitarian or through
those of an economist. They reflect a casualty decrease of from 21.38 per ntillion-
r.tan-ltours worked in 1927 to 5.45 per million-man-hours worked in 1934. To -Mr.
Earl G. Evans, to our operating officials, and to the rank and file of our employees
I take oft my hat and felicitate both him and them with all my heart. Our experience
Safety Section, el A R--Steam Railroad Section, N S C
477
Accident prevention is a problem that "ill lie solved primarily by individual action. We will never have adequate protection lor hitman life until the manufacturer insists on safeguarding every machine before it is offered tor sale; until the employer insists on sate equipment and safe methods of performing every job; until the worker makes safe practices a part of his sub-conscious habit; until the motor car driver becomes as courteous as he is in his home or office.
Permit me to cite just one illustration. N'ot long ago in a large gas plant, an executive of the company attempted to- enter the plant while smoking a cigar. The gateman, not aware that this individual was the vice-president, flatly refused him admission until be had deposited his cigar in a metal refuse container provided for that purpose. This gateman fully understood liis personal responsibility and lived up to the confidence reposed in him by his employer.
But. you might ask. can we bring about such a change in the habits and customs of 130.000.000 people? Can we get each person voluntarily to assume his share of the responsibility for the prevention of accidents? The answer to these questions, in my mind, is unqualifiedly "yes."
How? By continuing the same methods and procedures which have been em ployed so successfully during the past decade or more by our leading railroads and industrial 'organizations. In each location, in each industry, the work was started by one or two far-thinking individuals sometimes called safety men.
WEDNESDAY AFTERNOON SESSION
October 16, 1935
Transportation By Rail--Speed With Comfort and Safety
By ROY V. WRIGHT
Managing Editor, "Railway Age"
We arc in the midst of a speed age. Records of travel--in the air, and on the rail, highway and water--arc being hroken with such frequency that announcements of new records have lost much of their old force in challenging our attention.
With the introduction of the private automnhilc on a large scale and the increas ing use of the motor bus and the airplane with high speeds, the railroads have steadily lost passenger business for many years, although the trend started to turn hack tipward slightly in 193-1. In that year, however, it was less than 18 billion passenger-* miles, as compared to an average of 3 IK billions for the five years 1926-1930. A further increase will be registered in 1935. Railroad managements realize that they face serious difficulties in attempting to build up their passenger business, and that only by unusual and spectacular efforts, based on high standards of service, can they stage a comeback.
The public demands fast transportation, both passenger and freight. The demand for speed, as a matter of fact, has predominated over the demand lor safety. Air traffic has continued to grow, and the speed of highway traffic has increased trcmentluously. However, the cost in human lives ot this speed is startling.
An increasing proportion of the public, it would appear, is going to demand safety in travel, along with speed, comfort and convenience, and reasonable price. What are the railways doing to meet this demand?
The answer, in a broad way, is the provision of facilities over which modem and specially designed equipment can he operated successfully at high speeds with a maximum degree of safety. This may appear difficult, hut a study of developments indicates that the foundations have been wcil laid for a more intensive development of rail transportation at this time.
The rapid extension of the railroads, in the effort to open up and develop the interior and far parts of the country, slowed up in the early part of the present
Safety Section, A A R--Steam Railroad Section, NSC
481
fatalities is concerned. However, there were 5,794 automobiles registered for each crossing injury, and tiiis record is not so favorable.
Vour committee again recommends that individual railroads particularly stress
the necessity of their train crews and others giving adequate and liinely tsarninq to the public of the approach of trains to a hiqhivay crossinq; that -varninq from cnqinc should be continued until the crossinq is definitely reached: that the standards oi protection established by the Joint Committee oil Grade Crossing Protection he employed where necessary at crossings to facilitate uniformiy anil public under standing of the signals; that crossings be periodically inspected and maintained in sound, travnblc condition with all obstructions to the view removed wherever prac ticable; that advantage be taken of the opportunity to address school children and students of colleges and universities on the subject of railroad-hichwav crossing safety, no opportunity being lost to present the subject at luncheon clubs, automobile clubs, and any places where automobile drivers may gather.
THURSDAY MORNING SESSION October 17, 1935
Report of Committee on Non-Train Accidents
By E. B. PERRY r.; r Assistant to General Manager, New York, New Haven & Hartford Railroad
The reduction of over 46 per cent in non-train accidents to employees on duty,
accomplished in the past three years, is gratifying. However, the very fact that
material reductions have been so readily made supports the belief that a large
decrease from the 1928 figures is still easily possible.
We have felt that no good purpose would be served by a mere recital of statistics.
That which has happened cannot be corrected hut should he used as a basis for
thought and action to prevent recurrence. Your committee arc agreed that they
should outline plans fur the iuturc rather than recite history.
A review of the statistics indicates the major causes of non-train accidents fall
into the following classes:
Use of hand tools, apparatus, etc.; Collapse, fall, etc., of objects; Handling rails,
ties, bridge timber, etc.; Handling freight and supplies: Falls of employees not in
cludible in class (a) to (1).
_
(Report had been distributed in advance to all delegates.)
There has been a marked and steady decline in non-train accidents per million
man hours worked--the 1933 figures licing the lowest on record.
Use of Hand Tools and Apparatus
By II. R. CORE
Assistant to Vice President, Erie Railroad
All tools and machinery should be inspected at least monthly. Proper tools should be used for different classes of work. Reclaimed tools such as clawbnrs, cold ctnsc s. etc., should be thoroughly tested before placing in service. New men should he instructed in the use of tools and how to keep them in proper condition, loots should not lie left in dangerous places where employees may fall over them.
Metal spurs should be used on ladders. The use of a rubber collar on cold or hand chisels to prevent pieces of material trom flying is suggested. A SO ton air jack can be used at wheel pits eliminating use of jacks with lever which might sup.