Document 0gOpJo88mdZdMaGb7w2RyoXaR

lately iff :.-d by * r \vith n ivalvflt !! have iai cmical sound ity i^n. r.trol o c INDUSTRIAL HYQIENE ASSOCIATION Volume )7 SEPTEMBER, 1956 Number 3 Symposium on Threshold Limits Present Trends in MAC'*..........................................................................U\/rr .1. I'mtk The Need for Threshold Limits....................................................Mirim" Snrh*. MJK Prepared Discussion............................................................................ /// F. Swrfili. Jr. Methods of Kstablishims Threshold Limits.........................II. S>r,,,rr, MJ). ixti Prepared Discussion......... ..................................................Jlcrhrrt K. Shikinorr, I'h.Jl. Entcineerinif and Chemical Application of Standards ... .AlU-u }). Urn,nit. .S>J). Prepared Discussion....................................................................................\rtUnr t\ Slrtu Prepared Discussion *........................................................ Tht<*irr C. HVfiv*. I.L.li. 27% L171 tlTD U3I ;yji* Automatic Instrumentation hhi Am Pollution Momt-hun*;--A I'i:iw:':k.sx Report on automatic Directional Aik Sampling............... Will,", .1. .!/><* A Versatile Portable Aik Sampler.........................II. s. J<.</ <>,,( it. .V. .U</w..// -i`S ::un Determination up Internally Deposited R.AmoACTtv>: Isotopes prom Excretion Analyses..............^....................-....................Wriyht II. I.n,,,/>nnn :'u Criteria for an Evaluation op Noise ITiuhlems......... (7<#/ !:. iViUbuu*. 1`U.D. Flow Caurkatio.v of Hiuh-Volumk Samplers ................................................................ limmrti /). Trbheun, Sr.})., n mi /)*// .}/. ,\f~S. .'UP :'.'2"7 Recent I.vdustiual Hygiene Developments--A Symposium In the Field of Air Pollution..................................................................... lt> < .V. /)/ In the Field of Chemistry.............................................................Un/fth >1. >'..'<A. I'U.li. In the Field of Kntrineerinif.......................................................L*.*! SU, < . .. Sr.It. In the Field of Noise................................................................... ................. I'hh.jA., //. Hill In the Field of Radiation...................................... ....................................... S--` J. //*>>* fn the Field of Toxieuluify.............................................K. St"ki>j>r. 1`U.it. '.UO ".vj Hycienic guiue series........................................... .................................................................... President's pace ............................................................................................................................. Selected Titles and abstrats............................................................................................... Book Review....... .............................................................................................................................. ::.*4 AIHA 1 N WSTMIAL ASSOCIATES. OKHC^S. l)lKKlTn*<>-. A NO C'lMMMTKK* .............................. _A*at*c** Ssoustsiai. HYottxt AiaoCiArio* uumn.r. u the Ammon lnjutnai Hr*>*ne As* ^toeiaiiefl is Maretu June, September, *nrt December. N, S. nni >:<(ur: Hr.nnurr J tv*ara, A<ivisry Cilitur: Lietl* K- i*umc. Aauria<* Kdim". Wiij.um S. JmiViM.y. K.lnor !l ujj.i, l',r. Tutaue* EdiMie A. 0. CUmjs. Publisher; Dues Ft.ncswiT. EUttwrtat Aamietant. I'tihliratHMi mi EUitenal Q{- ftem. iGS North Mienieae Avenue. Chicara II. lUiewra. Swt*ent>uvn SA.im) |wr war >n the Lniu-O State); 34.40 per rear ie Caaaaia; tt.itf per year in outer eeunxrie*. .-ikivW tin- Jn. !Vv. iuu* vma ia 1T.U0. Cv>niiM, lS$<i, the Auttt'M l.NuurTKiAL HtuitSK Akm* iatimx Kntovwt eia** mat. trr Kay 3. ISO. at the Mat utflrv at SHeiawrenn. WiMu**n. nn>(*f tiw> Act San-n I'Ty. Thv A*uocan (itOCa'nUAt. KliiltSt Aau'tATU>N dVAKTULT reaerxea U>* rich! tu <->< all aUtvrtir.-xaoit* a(iJ tu ri.Yw.*e Wvtrtn. irt* ropy when it Lmo nwt meet tne htch pro^eaaional ta.Sr.U aUnuteti tiy me Awutivii. Symposium on Threshold Limits Present Trends in MAC's introduction by VVARREN A. COOK. Associate Professor Industrial Health and Hygiene. Schooi of Public Health University of Michigan. Ann Arbor he thinking today on the concept of Tthreshold limits of injurious materials, limits and the improper use of them. No where is the present concept of threshold designated by whatever term, has passedlimits more ably and competently expressed through an evolution to a gratifying m- than in the papers :imi discussions of this lurity. Symposium. Initially the need to know how little of a That the discussants might not have the toxic substance might remain in an indus very last word, it may be permissible for trial atmosphere without injury to those ex this prologue to assume in part thy preroga posed was insistently apparent- Such in tive of an epilogue? The fellmviug com formation began to be supplied through cor mentaries appear pertinent. relation of concentrations of injurious sub The hist publication of the American stances with observed effect on the health Standards Association Z-d7 Committee on of the worker for such materials as granite .Maximum Acceptable Concentrations of dust' and lend compounds.2 Results of short Toxic (lusts and Gns*s's is nrfmrtyd cor time animal experiments had been available rectly as 1!)4!) by Sachs who dcplnrvfl the even before the present century from such lack of revision of the 1041 Standard for investigators as K. B. Lehmann3 and later benzene at the obsolete level of 100 parts from Yant and others at the U. S. Bureau per million. It is to be noted that this ASA of Mines,4 with the classic combined long- Committee is now active in the revision and exposure animal experimentation and oc publication of MAC Standards for many cupational study on benzene by Greenburg3 of the materials on which information is in the middle twenties. available. As these threshold limit values became The term "maximum acceptable concen more numerous and were more widely ap trations" was adopted by the ASA fommit- plied. it is perhaps not surprising that mis tee for a number of reasons. The word "ac conceptions and aberrant usages occurred. ceptable" does not connote the legal control Some persons erred in considering the levels inherent in the words "allowable" and "lim more precise than the facts justified: others it.** but rather a simple acceptability with rejected them because the values could not out further implication. Also, the expres precisely fit all conditions of exposure and sion. MAC. has been widely used over the physiological response. And the detractors years and is now a pan of the language. In were for a while more vociferous and seemed fact the Germans adopted a wording which possibly to be more sound than the pro gives the abbreviation, MAK. so that this tagonists. . . term may i>e used in international conversa With rime, there has been a separation of tion. Their words as used in the title of a the valuable advantages of the threshold paper by Oettel7 are "Muximale Arbeits- platx-Konzentration." It is undvrstwaj that ?mmM *t tli Jniftt Svmho* u* amcbica* Is- Krc.trx* Aiwuww--Anemic** rAv*f**ne nr (Vwm*i ***taw InwcutWAt, Hvric.vi.vt^ u th* I9SA In- He*IU CsfOtiTnc*. UuifaM. Aonl 24. 1944. this same expression is !>eing used in the "MAK** tables of the Gorman Association for Worker Protection. =\i*= cas. *?i, si S: i S*. .-ko :tft m lilSOI: :^-n September, 1044 However, (here cun be no really valid ob jection to the term `'Threshold Limits" used by the committee of the American Confer ence of (Governmental Industrial Hygienists or to "Hygienic Guides," the term adopted by the American Industrial Hygiene Asso ciation committee. This Symposium would not hu complete without reference to the availability of the excellent A1HA Hygienic Guides to which reference is made else where in this .Journal. One of the most perplexing problems in arriving at threshold limits is posed by the cuncerigens. Stokinger's statement in this Symposium is the first publication on this phase of the subject. However, the use of the procedure suggested by Stnkingcr ;is ap plied to nickel carbonyl has already drawn some tire. (Quoting in pait from a private communication from Octtei whe publica tions7' on ".UAKV* include a well-consid ered presentation of the general subject: sourest that consideration he vea to indicating the susj>evted cancerigens with an asterisk with reference to a footnote that the hazard exists and consequently especial ly effective control measures be instituted. So man can sav today which concentration of .the several industrial substances is actu ally required to lie canceri genic . . ." This statement follows his abjection to the pres ent listing by the ACGIH of nickel car bonyl as U.Oul ppm on the basis of its al iened enneerigenieity, which incidentally Oettel's extensive experience with the sub stance causes him to doubt, while failing to include any acknowledgement of the known enneerigenieity of arsenic, chromates and asbestos. Says Oettel "In this I see a great dancer. The lists should in any event remain logical." Waters' discussion of Brandt's paper oc cupies the final pages of this publication of the Symposium, but it is believed that Waters would not wish his comments to be considered the last word on the subject of threshold limits--rather that his observa tions are limited essentially to the use of these values in legal codes, rigidly fixed by statute. As the last word in this Symposium, this introductory refers the reader to the concluding paragraphs of the paper by Crandt for his discussion of the philosophy of threshold limits. 1 I \ 1 References I. A. luu-nrs. R. H.. Thukmiw. L. It. i. J,. Thm HimJth n( Worker* ia Durey Trmaha II. F.miiwiw SHimm* Otiat lOrnit InrfuairTt. I'ahlim II.Hitt, limit. No. Ik?. I9SP. 1 Ks'snku. A. K.. Jcviac. a. H.. novisriKLa. i. J-. IUsttxj*. a. H- Tim^rwi*. U R.; Potw*ii* i Slma I'attrry I't.flt. t'um.m Hrmltk Hull. .Vo. yti. 1033. 3. I.mimzxs. K. M.: poot* pub. Iihcl in ,irr*<r far Hmq.mmm from tho JJOUV*. 1. Yamt. W. (*.. and roiloaauo*: Acuta Rnoonao Uuinra l*ia i ViMa Sm* N*w Commercial Or- canto Comt>ouivia. A <*t* <>( sanom jiublihe in Public Health Rrttort* tnnnt the IflWa. i. (lacr.Nat'ac. L.: Rental Poiaontnc an Indus trial Hazard. Pabbc Hr*llM 41. 1347, 1410. and l-l!*: 19M. 4. Amoriraa Standard A*oetatto: Standard* an At- rooiaMo- Cncontratu*n nt Toai Ouata and Caaoo. ASA. 78 E. :3th Stroot. Now York 17. Now Y<rtt. 7. Oi.itu. H.: 0>o maximal* A rtwitxviatz-Koasen tre turn <= MAK-Wortoi ^hadlichor 0ao. Damofr uiwt SUubo. Iilr Hrrrnl.u-m.immrnmfMfi. No. 2. SrOruarr. 1954. a. Okttu. H.: Oworhlicho Vr*iftunc* dureh G**c. Oiimofo uaS StauUarton. AtrAtr far Tonkplapn, 11:11. 1934. ' * , . The Need for Threshold Limits a 3 h u J h h U u d c c t: n d 4 t: tl c s b. F tt A f h n a t i MIRIAM SACHS. M.D. New Jersey Stete Oecarrment ot Health. 8ureau of Adult and Occupational Health Trenton. New Jersey Prohaiily one of the most basic needs in human endeavor is for man to have nn purpose as a ; oint of aim for individual interpretation, if this seems cryptic, an ex orderliness set to his manner of thinking. ample concerning a common substance may Everyone has a need for discipline, for be cited. boundaries to be drawn, and for limits to be Aimo.st everyone is familiar with the defined, it docs not matter that the only use threshold limit values for silica--for dust for some of the limits s defined may lie to with a free silicon dioxide content above ignoru them; they have still served their uO'c. the limit is given as five million parti- i > > f