Document VKjbzy2bj3gOo4e7QG1KnJKop

^oivmon^oUmrci'i N E W B R U N S W I C K , N. J . 0 8 9 0 3 Septem ber 6, 1974 R o b ert M. Schaffner, Ph. D. A ssociate D irector for Technology Bureau of Foods Food and Drug A dm inistration D epartm ent of Health, Education, and W elfare 200 "C" S tre e t, S. W. W ashington, D. C. 20204 Dear Dr. Schaffner: Johnson & Johnson has been cooperating with the Cosm etic, T o iletry and F ra g ra n c e A ssociation Subcommittee on A sbestos in Talc. In an effo rt to answ er the question about the req u ired degree of se n sitiv ity of the m ethod of a s s a y fo r a sb e sto s in talc, our sta tistic a l group has made an estim ation of a theoretical safe level of asbestos fiber in a baby powder utilizing the official TLV for asb esto s and the data on dusting of baby powder. The calculation shows that a substantial safety facto r can be expected with talc containing 1% w /w a sb e sto s f ib e r s . T h e re fo re , m ethods capable of determ ining le s s than 1% a sb e sto s in talc a re not n e c e s s a ry to a ssu re the safety of cosm etic talc. The re p o rt is attached herew ith. Since I have been assigned a new function at our R esearch C enter, I will be turning over my responsibility in the talc/asb esto s a rea to the R e s e a rc h D ivision of our Baby P ro d u c ts Company. I would a p p re c ia te your giving me the opportunity to p erso n ally p re s e n t them to you and your staff to a s s u r e a continuation of the cooperative efforts of Johnson & Johnson in this difficult problem. The following individuals fro m our Baby P roducts Company w ill be Dr. R. Schaffner -2- Septem ber 6, 1974 available fo r a m eeting to be set a t your convenience: D. R. P e tte rs o n , Ph. D. , V ic e -P re s id e n t, R e s e a rc h B. Sem ple, M. D. , D ire c to r of M edical and R egulatory A ffairs G. L ee, M anager of Applied R e se a rc h W, C. W aggoner, Ph. D. , A d m in istra to r of M edical and Regulatory A ffairs. I hope to h e a r fro m you soon. Very truly yours, JOHNSON & JOHNSON \j\3 - by: W. N ashed, Ph. D. A ssociate D irector of R esearch Domestic Operating Company Attach. SUBJECT: An E stim ate of a Safe L evel of A sbestos in Baby Powder T alc August 15, 1974 Sum m ary C om parative calculations have illu stra te d that lib eral dusting of an infant with a hypothetical co sm etic talc containing one p ercen t a sb e sto s fib er by weight would re s u lt in an infant cum ulative exposure of asbestos only 1/48, 000th as m uch as the T hreshold L im it Value - T im e W eighted A verage, which is considered safe for the rep eated exposure of in d u strial w orkers. On the b asis of these data any analytical procedure capable of detecting one p e r cent by w eight of a sb esto s fib e rs in talc would be adequate to in su re that the a s b esto s content of talc is acceptably low. D iscussion To date, a safe upper lim it fo r the percentage of asb esto s fib e rs in baby powder talc has not been estab lish ed . On th e 'b a sis of existing inform ation, however, it is p o ssib le to determ ine the m axim um concentration of asb esto s fib ers which could be p re se n t in talc without subjecting an infant to asb esto s exposure in excess of th e T LV . We can a ls o d e te rm in e if and what additional safety fa c to rs e x ist when talc is lib erally applied to infants. Since the TLV is the only available standard for a "sa fe " concentration of asb esto s fib ers in a i r ,'i t s use in providing a point of refe ren c e is justified in this instance. A c co rd in g to the F e d e ra l R e g is te r Vol. 37 No. 110, W ednesday, June 7, 1972, the p e rm issib le exposure (TLV) to airb o rn e concentrations of asbestos fib ers is as follows: "The 8 -hour tim e-w eighted average airb o rn e concentrations of asbestos to which any em ployee m ay be exposed shall not exceed five fib ers, longer than 5 m ic r o m e te r s , p e r cc of a i r ------ . " T h is lim it of 5 f ib e rs w ill be re d u c e d to 2 fib e r s p e r cc on July 1, 1976. E x c u rsio n s up to 10 fib e rs p e r cubic c e n tim e te r (ceiling concentration) w ill be p erm itted provided that the T im e W eighted A verage (TWA) does not exceed 2 fib e rs p er cc. The 2 fib er stan d ard and the ceiling lim it w ill be em ployed as the b a sis fo r calculations in th is m em orandum . F o r any p erso n exposed to asb esto s fib ers the allow able weekly exposure under the TLV is 2 fib e rs p e r cc of a ir fo r a to ta l of 2400 m in u tes p e r week (40 h rs . x 60 m in u tes p e r h r . ). If th is p e rso n w ere exposed to the ceilin g concentration of 10 f ib e r s p e r cc, the m ax im u m p e rm itte d e x p o su re tim e a c c o rd in g to the TWA w ould be 480 m in u te s p e r w eek (2 x 2400/10). In an e a r lie r r e p o r t ^ the to tal weekly exposure tim e for an infant to talcum pow der when the la tte r w as applied lib erally onto the diaper a re a was estim ated at 4 3 .8 m in u tes. D uring the actual talc application (13.6 p e rc en t of the total ex p o s u r e tim e ) the ta lc c o n c e n tra tio n was 8. 5S p a r tic le s p e r cc of a ir , and d u rin g the tim e the talc d u st se ttle d (86. 4 p e rc e n t of the total e x p o su re tim e) the av erag e c o n c e n tra tio n w as 4 .3 8 p a r tic le s p e r cc of a ir (See Note 1). Even if the 8.58 p articles per cc w ere asb esto s fib ers, the exposure of an infant would be le s s than the ceiling lim it of 10 a s b e s to s fib e rs p e r cc. T he to ta l weeklyexposure tim e of 43. 8 m inutes would be considerably le ss than the 480 m inutes p e rm itte d under the TWA for any exposed p e rso n , and in v e rse ly the safety factor for the infant would be considerably g re a te r. The safety factor under this type of exposure and for a hypothetical cosm etic talc containing only one percent asb esto s can be estim ated as follows: 1. C om pute the num ber of asb esto s fib e rs w hich any p erso n exposed to the TLV could inhale in a week, based on an inhalation ra te of 12.72 lite rs per m inute (See Note 2). 2 fib e rs /c c x 12.72x1000 cc o f.a ir/m in x 2400 m ins. =61,100, 000 fibers/w eek* 2. Com pute the num ber of fib ers an infant m ight inhale if we assu m e all talc p a r tic le s w ere asbestos fibers during the application of powder and during the dust settlin g period based on an inhalation ra te for an infant of 0. 584 lite rs per m inute^. (8. 58x. 136 + 4. 38x. 864) fib e r s p e r cc x 584 cc p e r m in. x 43. 8 m in s. = 126, 600 fib ers per week* 3. Com pute safety factor if all p a rtic le s w ere asbestos fib ers. 61,100,000/126, 600 = 483 4. Com pute safety factor for a hypothetical cosm etic talc containing only one p e r cent asb esto s fib ers by weight. 483 x 100 = 48,300 With a safety factor of this m agnitude it a p p ea rs that an upper lim it of one p ercent of a sb esto s fib ers in talcum used on infants would in su re that the exposure of in fants to asb esto s fib ers would be far le s s than the TLV for adults. Thus, an ana ly tical m ethod capable of detecting one p ercen t asbestos in talc would be m ore than adequate to confirm an acceptably low level of asb esto s in a talcum powder used on infants. *N orm al lung clearance m echanism w as not considered in eith er case; therefore, the num ber of fib ers shown do not re p re se n t fib ers retained in the lung. V ___N. S iv e rtso n M anager, S tatistical and Com puter O perations jdm Page 3 N o tes 1. In r e fe r e n c e (1) it w as shown th at the tim e sp e n t in applying ta lc lib e r a lly to the diaper site was 0.17 m inutes per application and that th ere was an additional tim e period of 1.08 m inutes per application during which the dust se ttle d . T hus, the total weekly exposure is 43. 8 m inutes = (0.17 + 1.08) m inutes per applica tion x 5 applications per day x 7 days per w eek. The exposure conditions outlined in re fe re n c e (1) w ere based on co n serv a tiv e assum ptions and rep re se n t exposure levels which w ere g reater than average. F o r exam ple, the data w ere based on applying the talc directly tothe diaper a re a from the container, which is the mode of application that c re ate s the g re a te s t concentration of talc dust, w hile in p ra c tic e m any m o th ers use hand ap p lica tio n . In addition, D r. Pooley() in his sim u latio n stu d ies p ro d u ced a g reater dust concentration by applying ta lc to a hard, dry su rface than would be p ro d u ce d u sin g a soft, m o is t s u rfa c e su c h a s an in fa n t's skin. In re fe re n c e (1) the a irb o rn e co n cen tratio n w as re p o rte d as 0. 243 m illion p a r tic les per cubic foot (mppcf) while "applying talc" and as 0.124 m ppcf during the d u st se ttlin g p erio d . T h ese values w ere converted to p a rtic le s p e r cc of a ir by m ultiplying by the facto r 35. 3 re s u ltin g in the 8.58 and 4. 38 p a rtic le s p er cc of a ir, resp ectiv ely , as stated in the body of this m em orandum . 2. A ccording to the data in re fe re n c e (2) an adult m ale at r e s t has a m inute vol ume (inhalation rate) of 7.43 lite rs per m inute and 28.6 lite rs per m inute when perfo rm in g light w ork. If we assu m e conservatively that an adult exposed to asbestos dust p erfo rm s light work one-fourth of the tim e and is at r e s t th reefourths of the tim e, his expected inhalation ra te is: . 25(28. 6) + . 75(7. 43) = 1 2 .72 lit e r s p e r m inute R eferen ces (1) C o m p ariso n of T alc D ust E x p o su re for Infants and T alc M in ers, ]. N. Sivertson, Johnson & Johnson S tatistical and Com puter O perations, Feb. 19, 1974. (Subm itted to Food and Drug A dm inistration on M ar. 17, 1974) (2) Biology DataBook, F e d e ra tio n of A m e ric an S ocieties for E x p erim en tal Biology, 1964, p. 220. (3) See R eferen ce (1), Section II.