Document aBMVLpQK76LoVDyGEz6Nj7X5B

FILE NAME: Asbestos in Hair Dryers (HD) DATE: DOC#: HD0 OCUMENT DESCRIPTION: :D/ZZZZZ& Z,ZZW/Z J' I E~~~-~~N~~~;-" ........ _.... .....w""" _~ _ .... -... ._.~_ HEALTH, SAFETY & JOHNS-MANVILLE CORPORATION HAIRDRYER ASBESTOS EMISSIONS APR 10, 1979 '-'" ,... ,.... , ,-, ... ,.. ~, ,Emissions of Asbestos Fiber From Hair Dryers Containing Asbestos Paper Insulation As a result of a petition filed by the Environmental Defense Fund with the Consumer Product Safety Commission, on March 29, 1979 the Johns-Manvillf! Industrial Hygiene Laborat.Q..:...r..Y commenced a series of tests to measure the levels of fiber emission from hand-held hair dryers containing asbestos paper insulation. The new hair dryers used in this . series of tests were purchased on the open market, while the "old" models were borrowed from employees. One model which did not contain asbestos paper was used to investigate the background level of asbestos fiber for the sampling and analytic procedures used in the laboratory. Ideally, such laboratory tests are conducted under "clean room" conditions so that the background fiber counts would be negligible. The volume of air emitted from the dryers and other considerations, however, made this impossible. Under any conditions it is good science to investigate background levels. The tests were run undel three different conditions. In one case, the air was sampled by passing through prefiltered water in a large plastic container. After the designated running time, equal aliquots of this water were filtered throuqh both Millipore ~nd Nuc]epore filters. These filters were then submitted to the micros~opic laboratory for examination by both transmission a!ld scanning electron mjcroscopy. '1'110 second method of the samp1in9 was direct sampling of the a ir from the dryel' using a hi crh vol um(~ sarnpJ ('.t. 'I'hc~ .' . .. - 1. - .. dryer was attached to a tube and all the air emitted from the dryer passed through the tube. In this case a known fraction of the air emitted from the dryer was drawn through a Millipore filter for a specified period of time. The air volumes were measured with a thermal anamometer and corrected ... for temperature. The sampling was also done under near isokinetic conditions so that fibers in all size ranges would be captured. In this case it was not possible to sample on Nuclepore filters, therefore, the only analysis which was carried out was by transmission electron micros- copy. The third method was to sample the air, with a high volume sampler, in the immediate vicinity of a simulated normal use test. For analysis by scanning electron microscopy, a I centimeter diameter section of a Nuclepore filter was cut out and mounted on an aluminum sample stub. This sample was then coated with carbon in a vacuum evaporator and then examined directly 1n the scanning electron microscope at 1500X magnification. Some of the pic tu res included in the report were taken at either higher or lower magnifications. Lower magnifications were used in order to show a larger and more representative area of the filter surface, whereas hi gher mag-nifi cations were used to show more details of the asbestos fibers encountered. All of the fibers encountered were chrysotile asbestos. This .J -- was confirmed by energy dispersive x-ray analysis. In several of the pictures there are very low contrast arti- facts that appear on the surface of the filter. These are the desicated remains of bacteria which grew in the water between the time the sample was taken and the time that the aliquot was filtered. These images ar~;not to be confused with asbestos fibers. For transmission electron microst;opy, the Millipore filters were first treated as recommended by the Millipore Corporation to collapse their structure, and then coated with carbon In a vacuum evaporator to "glue down" particles remaining on the surface. A three millimeter diameter portion of the filter was then placed on a carbon coated electron microscope grid and the filter material cleared using the cold finger acetone extraction method. Proper pretreatment of the filter media prior to the extraction allows complete clearing to take place within 30 minutes so that the possible loss of particulates is held to a minimum. After clearing, the electron microscope grid is ready for examination. For this analysis 15 complete grid squares were examined at a magnification of 48000x. The presence of chrysotile fibers was verified by both electron diffraction and by energy dispersive x-ray analysis. In order to quantify the amount .r of chrysotile fiber present, the dimension of each fiber bundle, fibril or clump was recorded so ~hat the mass could be calculated. The mass was calculated assuffilng a cylindrical .... , , . I 1 i l I i I ! I cross section for fiber bundles and a specific gravity of 2.60 grams per cubic centimeter. The mass of the clum~ ._' w~s ~""'-i'" nc,l--u-d-,e._d,-,i"n.. - t-h.-,e- calc--u--l,a- t--i_o.-,n,-- '.b,.e-c-"a-u""s-e-,-""in. -_m.,--o-s-t~- ca"se~. s, t h e y w e r e m i x t u r e s o f c h r y s o t i l e _._ _ _--'"'---.- ... " ......--. "'" ..~ ,...... __ .~, fibers v and other unidenti- ------- fied materig.1&-; .-- - I t ' - _.. w a -' s - - not ----- - - pos - --.-- s i b l e in most . _., c a s ~'-"-~' e-._s-,...- to count ". ~.--. .. an- d-- m-e-a.s- u- re-.t-h-e--d-i- m-e~n.s-i- o. n~ s-o-.f-.~- all,,fiQ,e.rs.J.n......a...cJ-ump. The - - - vast majoEJtjC_q,f_.t}1e.se------c-l-u--,m..~p..s - co~. n.t.ained onlY."shor,t chrysotile f i brils ~----- --w h i c h , w o u l d contribute very little",:to. the total ma?s , , - - - - - of fiber ~~t 1::ted,.~_ It is imperative to understand the varlOUS ways numbers are to describe airborne asbestos. Current OSHA standards for occupational exposures to asbestos are: used "Standard Effective July 1, 1976. -,, The 8-hour time-weighted ?,),) )/// average airborne concentrations of asbestos fibers to which f . <,p,l-; / any employee may be exposed shall not exceed 2 fibers, longer than 5 micrometers, per cubic centimeter of air, as determined by the method prescribed in paragraph (e) of this section. Ceiling concentration. No employee shall be exposed at any time to airborne concentrations of asbestos fibers in excess of 10 fibers, longer than 5 micrometers, per cubic centimeter of air, as determined by the method prescribed in paragraph ((') 0 f th i s section." The extremely heavy occupational E'xposures of the past "d1ich are responsible for the morbidi t J' and rnortali ty expericncu of occu- pational cohorts have been orders of magnitude (i,e. lOX, lOOX, lOOOX) higher thell1 permitted by present OSlIA standard~;. .. However, to put fiber levels measured in the hair dryer tests into perspective with occupational exposures, even the airborne levels predicted in laboratory experiments by J-M would not be statistically detectable u~,in.9.._t.he. sampling and ana, l y t J C,? I techniques for ..9_9C.1,lpa!::.ional - - --.. ...... > -- - ~--'- ,- - .' ..........- to the OSHA asbestos standard. exposures pursuant tj":~I.~. (,j For example, in the membrane filter method for analyzing occupational exposures to asbestos, it is acceptable to count a few fibers on unused, new blank filters taken directly from the box. A count of up to 5 fibers on a blank is con- sidered acceptable according to the NIOSH document P&CM1 239, which describes the analytical method (Asbestos Fibers In Air). If a personal sample is taken for two hours in the workplace (assuming a 2 liter/minute sampling rate) and a counting area of . 005 nun? (a size in the recommended range) is used on the microscope, each fiber counted "represents" 0.007 f/cc if 100 fields of view are counted. E...v.e.-n'--i--f---t-h-e -- m::a-x--im--u--m----2----h-o,-u--r_.b--u. -n-d---l-e.---- c- o-u~-n---t,- .-e...s,,-t-_i.m - at--e---- i~-.n~-. the EDF petition is ~S.1J.I'-.1.:'_C;Lt9_ b~ .Qnth-ely airbor~~, ~n.,l~ _~13 of space, that would gi V.C.!.- 2..:~~,~ = 0.53 X 10- 2 18 X 10 0.005 f/cc which is.. lc,f:;stha.l1.whut a.single ...fiber "represcnts" in ,the' above eXi1mple and in \vhich is predictably found on blank. nc\"c!used filters. The extremely small nUPlbers used here arc fur purposes of illustration only, as it is widely known that th,,~, occupational samplil1g/analyti cal procedure is not Ci:tl)Clblc of /. reliabl y mOi1surins; at these> c~xt.remely low levcll~~. .. The purpose of the discussion of occupational exposures is not to suggest that non-occupational exposures should be permitted to approach OSHA's permissible occupational exposure levels, but r~~~r_~1::.o__~dc1re!?~_.?~d_. ~r~~uJ:..e .the. _EDE...data which that fiber levels emitted from hair dryers may approach i~ply ...- " ..- ... ...__ . __ . -=----'~-.--- ~ ~--_ ~._ 'I.n",, _ _ h " ,. h' '. .. :.... OSHA' s pi')LIllis!:dJ2.1~~~I?~tLQ!lJ~1.L1.eveJs.."....S~_c~~-.:.a~ _inr~Ie~.~~_._~~ 1 sc_ienti ~ i~l.L..s.Re.cJQ.\!$.~.. More sensitive sampling/analytical techniques utilizing electron microscopy must be used for the very low levels encountered from hair dryers, in contrast to the method for measurlng occupational exposures to asbestos. Even these more sensitive techniques have limitations and studies to improve the accuracy and precision of electron microscope techniques are on-golng. For example, two quotes from EPA Technology Series, EPA-600/278-038 (June 1978) are appropriate for this discussion: "The presence of a few large bundles of fibers strongly I influence mass concentration estimates." { and "The conventional transmission electron m1croscope lS superior to the scanning electron microscope for detecting and identifying chrysotile fibrils." To paraphrasc the> above, [CIV fiber bundles generally stron9Jy bias the mass conccntration (i. e. too high) and 'l'El1 is !c:upori or for t1w evaluation of the smaller fi brils .. . \ & ~ --'- ,Since EMV A!s9~}a 1:..es __ rep'~r-._t-e_d. su .. __ch extr~~~.!y"_ ..-.... .. ~!!l~. l l . . . J I l a s s - q u a n t i t i e s , an'-d---p--a..r..t-i.c..u..,l-a-_rl_y__si_nJc_~_e_.._th__ey..__.d__i..s~ .,t~_u.....r.~_b..~.e_ ,~d_._.. the ~ asbestos ~- liners before ~ .~ ' .... __ _. _ A _--. .- conducting a ~---- test for th.e._-r-e-l-e-a-_se._-o-f-_a.sb.e.s-t-o--s---f-i-b--e-_r.s_,---s- er-io-us d~ubts must. be raised... as.... to. the.... validity of. their.....~~:ta ..and.. tb~ c o nc ,--- l..u- -s - i...o..--n.....s ...r"" e a c h e d _ t h e r e f r o m . . Specifically, the .'E..".D.F petition describes the EMV tests as follows: "All size dryers had asbestos liners. This was confirmed by examining a small section of the liner by the SEM/EDXA method described before. When this confirmation took Place( before the test for asbestos release, the cut edges of the liner were sealed with glue." / ......"'~- ---- ---.......... -,. The cal...9J::l:l~t.i.ons....in_,the".EDE.._.P.e..tition ...are~'l?-.~zzling). The assumed a v e r a g e b u n d l e s i z e o f 2X2X30 m i c r o n s i s q u i t e l a r g e . ________~~_________ -.--'~ - ' _________~~. ".,. __............_ _......._ .........,_"--_ ..' ..--.............. ~ .-....,4'...,.._ _~_... ~....... Assuming a _ - - - - - , __ 2xnQ.Q.....micron __J.f.. .. 2X2X30 ...box. shape i s assumed, that gives a siz~.,. --....~-.~-......__ ..._ ..........~ <'~ ~a ,-. 4P _ _ _ .~_ ~ ~~._~ ... , , - . _ ~,~ ~.~-'- -- v.olume9L.1.20XlO-12 cm 3 . -...-.. ....--"~- - ... ----~~.;;:;.~~~..:;;,...- A specific gravity of 2.6 gives a mass of 12 3l2XlO- gm or (~-?-.-, . ---"-. JLg_,,:which QQ~.!?--,~S~:t..- a~r.~~_ wi th tl)~P,,,~,,?3_~ , -'f ,"l g i v e n i n t h e f o o t n o t e t o T a b l e 1 . _ _ -=' .--....~_ ~.,,_ _ _ _...-_ _~,.- ~ __"'_..... _ ..... __<---.-._~,___ ~.. 'r"'_ _ ~. ..-,.,J"""~---------~' A ~L~.__f~a 1 i !?,t..i.c._.s.=?.!?-}!!pJ:.i.QD.__Q.f_?_(C2Yf-_:h!.1.9 El.L..S!l ape )wou 1d Yi e 1d a ... ,,- ~~~.------ volume of 94.25 cm3 and a maf::_~__c;.~~<;.u)..~ti?ng_C'(.?4?_1?_9'\ instead , ~'->VI.. "'-~ __ o f .52 ng. -----,--~-.--. ------ Since the EMV study: 1. Found few bundles, which bias the ma.ss on the high side, 2. Used questionable scientific procedures, and 3. Presented mass calculations which are incorre~L, ~he EMV results are of questionable validity and emphasize the ~ need for additional testing. The water sampling (duplicating the EMV test) done by J-M involved four dryers (three with asbestos paper) and four tests .... ::. (one of the dryers with asbestos paper was run twice.) T:went: grids were counted.. for _each _tes.t, -witJl only.. a single bundle ---------------~- - <. -.....-;...;._---- ...-........ . (qu_it_e._l_ar_g_e _a_ nd_ non-respirable ~---......---n.---~.'"".-'.. -.) observe.-d -,.i.n-..-' ,t_~o_.. ~ t a l ~ in. _a_l__lJ"t~he""~~ ...... tests. ~ T~9_z:1_trq~j~_j~JLt.he.>.. nuIDP_~J;_..9f.__ bundle s _g iyen_ in Table 1 qJ j:,h.Lj:P.E.~p~J~JJ:j.~oJt"". No-- n-e--- o-f~ --t,h- e- _.se__ numbe-:r:s._...s-ho~--u'"ld-,- be viewed as definitive. ~--------... -.- Rather, the lower SEM counts in the J-M / I data and questionable scientific procedure in the EMV tests point to the need for additional studies. J In addition to the water analyses conducted by J-M by SEM, TEM work on the water samples and TEM work on the air samples were done by J-M, which provides us with additional data not obtained If by EMV. The mass determinations by TEM are significantly lower I than SEH mass estimates in the EDF 'rable 1. (p "-....03 using 2 tailed Wilcoxon 2 sample ranks test). When onc considers the conclusions in EPA'S Technical Series, EPA-600/2-78-038 (June 1978) regarding the significance of a lo~ count of bundJes and the fGlct that moist.ure is normGll.ly present in a bathroom which suppresses dust, that exhaust fans or windo~s are alwClys present to remove fibers <lnc1 that routine vactlunung _. ewd cleClning \\'i11 u.lso remove fiber, Lhe lower order of ma9ni tULlc' - - "". -~ --~---'- -- - . - -- '. - - I)f the mass (as determined in J-M's TEM Glnillysps) which was " e found to be emitted from the dryers lead us to conclude that the f~~ahle.-l-o-the-F,DF--peti.tiQI}__ j~J:1_ich_ .'1,'.a b 1-e_.~~~. _4__. _____._...... contructed from the highest reported finding) are at 1~9!:)_.t....t.~,Q. r--- >/...,,~_ ................ - ...- ............ '.,. r~~ to the range of the EPA surveYA___of_Jl;rban_ .. and_~ ~ural.._aix.: ~ _ _...--........ =-~~ ".,~._,-,.J""-~'''- r., '" ""'" as set forth ..-.---._ i n T a b l e 4 i n t h e EDF p e t i t i o n . ~~,_"I(:.~""'""""'''''Il),.~''''~'<kI:~''''''',k'''',,,~_~o_'''''' "~:'''' ''I' ~--":",. '1> ....~ At the same time, . it should be noted that we question the accuracy of the numbers reported in Table 4 and their validity and application in assessing potential risk. () J ,i . .. The quantitative analysis of asbestos fibers by electron microscopy is not an exact science. The precision is extremely poor when compared to chemical analyses in general. In addition, because of the very poor precision very little is known regarding the accuracy of analyses by electron microscopy. Finally, there is very little agreeltrent among workers in this field regarding the methods that should be used to collect and prepare the samples for this kind of analysis. However, most worker~ do agree on one majqr point. The transmission electron miscroscope, and not the scanning electron microscope, is the instrument of choice for this type of analysis. Only by the former method can the extremely small asbestos fibers normally found in the environment be detected and characterized reliably. The results obtained by the two methods in this series of tests demonstrate this difference quite dramatically. c~ One of the princip):-e sources of error in quantitative electron microscope analysis can be traced to the extremely small fraction of the sample which is actually examined. In many cases the detection of a single fiber requires a multiplication by a factor as large as 1,000,000 to determine the final concentration. Even if there were no errors involved in the collection or prepal:atioll of the sample for exawinaticTl, there is irreducibJe stat.istical variation in-counting that can be a m~jor factor. In this type of analysis it must be ~-ecognizcc1 that other errors are unavoidabJ e, therefore 'ltIe - 11 - .. must be content with the fact that errors as large as a factor of 10 will be commonplace. In consequence, very little ./ credence should be placed on the absolute value of any numbers reported by these methods. They are only indicative of the approximate quantities of material present . . " . .~ '" The petition filed by the Environmental Defense Fund asking for a recall of all hair dryers containing asbestos in- sulation, -assumes_the data pro~ided by EMV Associates were accurate. Furthermore, the petition assesses the potential risk involved by making comparisons with data obtained by other laboratories by entirely different methods. Because of the intrinsic inaccuracies of the method- ologies, one cannot make meaningful comparisons of data obtained by different methods in different laboratories. The only way ln which any degree of consistency might be obtained would be in comparing results within a single laboratory by the same analyst. In any event, such data cannot, and should not, be used as has been done by EDF as a means of comparing the risk associated with exposure to these low levels of asbestos fiber. Those who do make such risk assess- ments are doing so with the apriori assumption that any exposure whatsoever to asbestos fiber can cause dise3se. Hmvev("r, there is no evidence to support such an assumption. All available evidence leads to the opposite conclusion. Thero is an incrc'<lsing body of evidence which indica tes that () exposure to very low levels of asbestos fiber, as found in non-occupational and non-paraoccupational situations, are not responsible for disease in man. Several arguments in this regard are presented in the attached addendum to the testimony of Dr. J. P. Leineweber before the House of Representatives Subcommittee on Elementary, Sec6~~ary and Vocational Education. This document, together with the documentation in the form of published papers by recognized aufhorities in the field, is now. part of the record of HR 3282 now before the House of Representatives. There are two additional concepts which are put forth in the BDF petition which must be corrected. First, they imply that all of the fiber which is released from a hair dryer will accumulate and remain in the room in which the hair dryer is use::1. What they did not consider is the fact that homemakers normally clean their homes on a regular basis. Each time a room is cleaned with a vacuum cleaner one would have to assume that at least 90% of the accumulated fiber would be removed from the environment. Wet mopping of a bathroom floor would probably remove an even greater perc'en'tage of any accumul ated fiber. In any event, periodic cleaning will remove a significant portion of any dust. S(~colldly, from reading the EDE' petition, one might (Jet the impression t.hat all of the fiber relea~;ed from the dr-yer \vill be inhaled by the user. 'rIlis is milnife'O>stly not-_ so. I Based on 3xistina knowledae, loosely bonded ashest.()s r;m8r as an insulator in the barrel of hand held hair dryers represents an inappropriate use of asbestos. We believe that non-locked-in uses of asbestos fiber, which result in the release of fiber to the ultimate user, should be:~eplaced with appropriate substitutes. However, it must also be recognized that there is no evidence to indicate that the u'se of hair dryers containing these asbestos papers poses a health hazard to anyone. The fiber concentrations emitted are, in fact, consistent with those found in urban environments for which there is absolutely no evidence of risk. In conclusion, the manufacturers of hair dryers should be requested to discontinue the use of asbestos paper. However, the general public should also be informed that there is no evidence to indicate that the continued use of hair dryers containing asbestos paper will pose a health hazard to anyone. Therefore, such hair dryers need not be recalled. We conclude from our review of the EHV data as well as from the results of our own studies that asbestos fibers released incidental to the usual use of hair dryers creates no health hazard. Thi~ is entirely compatible with epidemiological of asbestos (noll-occupational and non-paraoccuputjonal). The absolute numbers in the EDF petition and in this J-M study are meaningless from a health hazard point of view. What is meaningful is that small numbers of fibers are being observed and that most of those are either non-respirable or too short to be biologically active. The evidence suggests that the EMV results overstate the mass of asbestos emitted by hair dryers. Furthermore, even the highest airborne fiber levels that can be calculated using unrealistic assumptions (e.~. all fibers remain airborne) predict airborne fiber levels orders of magnitude below current permitted occupational levels. o