Document RanRXR8ob9QX8a8y520Lo4mdV
GRACE
C*ntrvction
ivltion
PLAINTIFFS; 1 ,, 1XHIBIT
To: B. M. VIning From: B. B. Locke
cc: V. F* McCord E. S. WOod
Date:
Subject
August 16, 1977
CPSC Risk Assessment
CC1C60S7
As you requested, please see the attached CPSC Risk Assessment turned to papercllpped Table 1 which Z have marked up per- our discussion. We were talking about CPSC estimated cancer death rates between 10 and 1,000 per million. They are derived from the table;
I. A. 8 hr. TWA in use of joint compounds assumed: 20 f/ml B. 1 Tear Equivalent Exposure @ 4 das./200 day year: 0.4 f/ml C. Enter Table ( 0.5 f/ml (approx. 0.4 f/ml) and read 13 deaths (approx. 10) per million
II A. 5 Tears of heavy exposure @ 0.4 f/ml annual equivalent calcu lated as being same as 1 year at 2.0 f/ml
B. Enter Table @ 2.0 f/nl and read 990 deaths (approx. 1,000) . per million
III. A. If the 1 Tear Equivalent Exposure were 0.1 f/ml, B. (This is .same as 5 f/ml 8 hr. TWA for 4 days or 20 f/ml 8 hr. TWA for 1 day) C. Enter Table @ 0.1 f/ml and read 0.02 deaths per million and relative risk of 1.0000006.
IV. A. 'B.
C.
If the 1 Tear Equivalent Exposure were 0.01 f/ml, (This is same as 0.5 f/ml & hr. TWA for 4 days or 2.0 f/ml for 1 day) Cols. (4), (5), and (6) can't be calculated from standard integral Tables (one attached and papercllpped). Cols. (1), (2), and (3) are shown, however.
In closing, let's again note chat this CPSC model employs a multi plicative combination of several adverse assumptions.
RHL/cf
B. H. Locke
UNITED STATES GOVERNMENT
Memorandum
U.5. CUN5UMEH PRODUCT SAFETY COMMISSION
WASHINGTON. D.C. 20207
TO
THRU
Don Clay, Acting AED for Engineering & Sciences gate: June 3, 1977 Robert M. Hchir, Actg. Deputy AED for Health .Sciences K*7
Steven Bayard, Ph.D./SPSC
Risk of Respiratory Cancer Due to Low. Level Exposure to Asbestos from CT: Speckling & Joint Taping Compounds
Summary & Discussion
.
A model for lifetime risk assessment of death from respiratory cancer due to consumer use of asbestos containing vail taping compounds is presented. Based on heavy exposure four times a year for 1 year, increased risk of death from respiratory cancer is estimated at 10 per million. Por fiye years of exposure at these levels, however, the risk Increases geometrically and is estimated at 1,000 per million or
* 1 per thousand.
061660?$
Por consumers using .ready mixed spackling compounds to fill a few small holes and doing a little.sanding, the model predicts negligible risk.
Ho quantitative risk assessment was made for asbestos exposure from the
artificial ash adorning the emberized gas logs since there are no known
measurements of the airborne fiber content. It can be assumed, however,
that whatever air concentrations are present, they expose the home occupant
to a repository of free fibers continuously vs. only intermittent exposure
for the wall taping compounds. . The risk from these ashes, therefore, may be considered at least as high as that from the wall taping compounds.
A. Assumptions
In order to compute a risk assessment of the use of asbestos containing wall joint compounds, many assumptions had to be made. The model used is mainly that of Enterline and Henderson (1976), which in turn was derived from data on amosite asbestos factory workers and asbestos insulation workers (Selikoff, Hammond and Seidman, 1973). Measurements of asbestos fibers longer chan 5 microns from work with wall taping compounds were taken by Rohl et al (1975). Projections of consumer use of taping com pounds are my own and age central death rates frpra respiratory cancer were based on the 1970-71 vital statistics of the United States.
The assumptions used in the risk assessment model are presented below; references for each are given.
rl
1 i
COvlB.'imtNl MmTiwCOfllCl;nt
IO
?& 2
1. The dose-response relationship between asbestos and lung cancer is linear (Entcrlinc and Henderson, 1976; McDonald, ec al, 1974). This hypothesis assumes no threshold.
2t Time to tumor is dependent'on dose and can be described by a log normal distribution with median time to tumor t ;
t - 98.65(1) 1/3
where D m 8-hour time weighted average dose in fibers/ce and a standard deviation of 1.5 f/ce. (Enterline and Henderson, 1976, based on Jones and Grindon, 1975).
3. Competing risks of death for the first 40 years following exposure are considered to be normal.
.--
4. Risk of asbestos caused death after the first 40 years following exposure is considered to be aero.
5. Effect of dose is cumulative and is assumed to have the same effect as if that dose had been accumulated in the first year of exposure.
4. Intermittent exposure with occasional fcigh'-peaka has the seme
cumulative effect as continuous exposure at double the dose
(Enterline, et al, 1972; Hicholson, 1976).
061SGCS9
While assumptions 1-5 may seem' a hit unclear, the total effect is to present a cumulative dose-response curve of the form log dose-log response. . This is shown in Figure 1. Explanation of how these figures were derived is given below. It is emphasized, however,, that this model is to be used for low exposure estimates. It does not fit the data for high or long term exposure -data.
*
e. 3
B. Derivation of Total Cases Caused by Asbestos Exposure
Besides the assuciptlons 1-6 above, the major data used to estimate the total cancer deaths attributable to dose were the Selikoff data on 294 factory workers who had been exposed to asbestos for 3-11 months during the years 1941-1945. Estimates of the concentration of asbestos dust during this period averaged 30 f/cc. Since the average exposure was only 5/8 year, the equivalent concentration was figured at 18.75 f/cc /day on a 1 year basis. By assumption 2, the median time to death from respiratory cancer is 37.1 years. Also, by assumption 2, the log normal distribution shows chat for the 28 years of followup used in the Selikoff paper only 24.4Z of these deaths would have o'ecurred. Since the adjusted relative risk of these workers was 2.95 (Enterline, 1976), and the age central death race from respiratory cancer (ages 35+) was 350/million, the number of respiratory deaths which-could have been caused by the asbestos exposure was the solution to
28(.000S50) +.244 X
(.000850)
- 2.95
or X .190205 or 190,205 deaths/million. But, since only 40 years of exposure a^re considered (assumptions 3 and 4), assumption 2 allows only 57.3Z or lb9U)00 lifetime cancer respiratory deaths per million exposed.
By assumption 1, the number of potential cases by dose can then be cal-^^^^^*
culated and risk estimates can be derived from these. This is shown in Table 1, along with the calculated relative risks. Here it is seen that excess deaths and relative risks do not increase linearly with Increasing dose but in a geometric manner.
C. Estimates of Exposure Levels of Consumer Users of Wall Taping Compounds'
Rohl (1975) measured peak fiber concentrations of ten drywall taping com
pounds during sanding, dry mixing, and floor sweeping. The average peaks
were as high as 47 f/cc with the highest individual peak of 59 f/cc. Based
on these peaks the 8-hour time weighted average was estimated as 10 f/cc. Taken
with assumption 6 that high intermittent exposure was estimated to have
doubled the effect of continuous exposure, this estimate was increased to
20 f/cc. If there are four uses projected per year, the estimate of yearly
equivalent is '
20 f/cc/dny x 4 days 200 days/ycar
.4 f/ce/day for 1 year
l
L ife tim e R e s p ira to ry Cancer Deaths 1,000*000/ (lo g scale)
FIGURE 1. Response vs. Dose for Low Level Asbestos
0
Exposure. -Asbestos Induced Respiratory Cancer Deaths per Million Lifetime vs. Daily Exposure (f/cc) for 1 Year. Estimates Based on the Model ,
X Average Daily Dose f/cc (log scale1)
TABLE 1. Lifetime (40 Year) Risk Estimates of Respiratory Cancer Deaths
Median Latent Periods and Relative Risks are I#ncluded,
0C1PC102
(0 (-*)
()
T3h
8-Hour Avg.
Latent
Potential
Daily
Periods
Cases/
Exposure
Tears, . , _ Million
Level-D
(<&\
t98.65(w) 5/* &&aJT *b
" /JDJUivrso^erea#tn/eToixf*XAt)*t*d-^^ lO -n *
^ .OOl
.0 1
'A
48 6. MS'}.?
124.3
lO
ro ( to
5,072
so* Co
Proportion Developed In 40 Years (log normal)
.coi&q .0026
Asbestos Induced Respir. Cancer . Deaths/ CWx(4)
'
4oiqx
13
CO
Relative Risk .--
(3)+850x40 850x40
" {.0000006 1.00038
1
98.6
10,145
.0130
132 .
1.UU38S
2
78.3
20,290
.0488
990 1.02912
4
62.1
40,578
.1488
6,038
1.17759
8
49.3
81,155
.3030
24,590
1.72324 '
16 18.75
39.1* 37.1
162,310 190,205
.4776 .5727
77,519 109,000*
3.27997 - 4.20588
* So iw.:
Mtk t.r
CuyJk
So&ckt CM.
\
' -pi,
e.p^a, a/ST.-P
U -2.(6
4 <pbt-AcA a-J
cAp 4-o-^>-^4-
oj eu o 00I ^ o-^
*4 .(^
4^ ''O.ofl Q-& * <.
0 A^l
(3 -- ^. jL- ^
M CM. o. OOOO { 5
tf 4 Thus, based on the.results of the model, Table 1, those four uses in 1 year with heavy exposure vlll cause an additional 10 lifetime respiratory cancer dcaths/million. Continued use for five years will, by assumption 5, raise that estimate to 990 (see Table 1) deaths per million.
L
' 06166103
I,
REFERENCES
Enterline, P.E.; DeCouflc, P.; Henderson, V: Mortality in relation to
occupational exposure in the asbestos industry. JOM, Vol.'14, No. 12
pp. 897-903. December 1972
Enterline, P.; Henderson, V.: A Model for Extrapolating to Low Levels of Asbestos Exposure.' Presented at Conference on Problems of Extrapolating the Results of Laboratory Animal Data to Men and Extrapo lating the Results froo High Dose Level Experiments to Low Dose Level Exposure, Pinehurst, N.C., March 11, 1976.
.
Jones, H.B.; Grindon, A.: Environmental factors in the origin of cancer
and estimation of the possible hazard to man. Fd. Cosset. Toxicol.
18:251-268, 1975.
#
McDonald, J.C.; McDonald, A.D.-; Gibbs, G.T7., et al: The health of chrysotile asbestos mine and mill workers of Quebec. Arch. Environ. Health 28:61, 1974.
OBIBGIO*1
Nicholson, H.J.: Case Study 1: Asbestos--The TLV Approach. Occupa tional Carcinogenesis, Annals of'the New York Academy of Sciences, Vol. 271:152-169, May 1976.
Sohl, A.N., et al: Exposure to Asbestos in the Use of Consumer . Spackling, Patching and Taping Compounds. Science, Vol. 189: 551-553,
8/15/75
Selikoff, I.J.; Harmond, E.C.; Seidman, H: Cancer risk of insulation
workers in the United States. IARC, Biological Effects of Asbestos, Lyon, France, 1973.
"
I
STATISTICAL TABLES
FOR BIOLOGICAL, AGRICULTURAL AND MEDICAL RESEARCH
nr
Sir RONALD A, FISHER; Sc.D., F.R.S,
>
FORMERLY ARTHUR BALFOUR FROFRSSOR OF CENXTICS, UNIVERSITY OF CAMBRIDGE, AND CALTON PROFESSOR, UNIVERSITY OF LONDON. HONORARY MEMBER, AMERICAN STATISTICAL ASSOCIATION.AND AMERICAN ACADEMY OF ARTS AND SCIENCES. FOREIGN MEMBER OF THE AMERICAN PHILO* SOPHICAL SOOETT. FOREICN ASSOCIATE OF THE NATIONAL ACADEMY OF SCIENCES OF XHZ .UNITED STATES OF AMERICA. FOREIGN MEMBER OF THE BOVAL SWEDISH ACADEMY OF SCIENCES AND THE ROTAL DANISH ACADEMY OF SCIENCES AND LETTERS. MEMBER OF THE PONTIFICAL
ACADEMY Or SCIENCES
AND
Secies
FRANK YATES, C.B.E., Sc.D., F.R.S.
SAD OF STATISTICAL DEPARTMENT, ROTKAMSTZD EXPERIMENTAL STATION, AND OF THE RESEARCH STATISTICAL SERVICE OF THE AGRICULTURAL RESEARCH COUNCIL
AND THE MINISTRY OF ACEICULTUEE
SIXTH EDITION REVISED AND ENLARGED
HAFNER PUBLISHING COMPANY INC.
NEW YORK.
Table Hi. The Normal Probability Integral
i0
*. 3
4
S * 1* 9
0*0 0* JOOOO 49801 * 49101 48803 48405
0'S 46017 456*0 43**4 448*8 44433
0*1 4*074 41683 4**94 40905 403*7
O
*
O
o*2 .
38*09 37**8 37448
36693
' "4
34438 34090 337*4 3 3360 3*997
O-J 30834 30503 30153 99806 39460 0*6 *74*5 *7093 96763 96435 36109 o*7 *4*96 *3885 *3376 *3*70 **965 0*8 *1x86 *0897 *06x1 90397 90043 0*9 X8406 18141 17879 17619 17361
48006 44036 40x39
36317 3*636
47608
43644 39743 3394* 3**76
47*10
43*5* 39338 33569 3*9*8
46813
4*838 38974 35*97 31561
464*4 4*465
3859* 34837
3*7
*911$
*S7S 33663 *9766 17x06
*8774 *5463 33363
19489 16853
*8434 *3*43 33065 19315 16603
38096
*48*3 **77
*8943 *6354
37760
*4S*o 3*476 18673 16x09
* 1*0 * '
VS
*3 **4
>$866
*3587 11307 o*o 96800
80757
156*5
*3330 *13*4 93098 79*70
IJ386 *3*36 11X93 93418
77804
15*5* **9*4
*0935 9*759 76359
*49*7 137x4 10749 90*33 74934
14686 **307 10563 88508
733*9
*4437 X3303 *0383 86915 7**43
*4*3* 13100 10304
83343 70781
14007 11900 10037
*3793 69437
13786 X1702 98525 83364
681x3
*5 66807 653** 64*33 63008 6x780 60571 59380 58308 57053 539*7 p6 54799 S3899 3*6*6. 5*53* 50503 4947* 48437 47460 46479 455*4 *7 44585 43633 4*7*6 418x5 40930 . 40059 39*04 38364 37538 367*7 p8 3593 35*48 34380 336*3 3*884 . 3**37 3*443 3074* 30034 *9379 **9 *87*7 *8067 *74*9 96803 36190 *3388 *4998 *4419 *385* *3*95
ro V* rs rj *4
**5 -r6 *7 9*8 *9
**730
17884 *3903 07*4 ^0^81975
9*916
*74*9 *3353 10444 79763
*1699 17003 13*09 10x70 77603
9x178 16586 1*874
99<>3* 73494
90673 16177
**345 96419 73436
\ 8*097 L 466x3 * 34870
18658
60366
43*7* 3364* *477* 18071
58677
4396s 3*641 24019 *7509
5703X 4:693
3*667 *3*74 16948
534*6 4*453 307*0 **S57 16411
90x83 *S778 132*4 93867
7*4*8
*9699 *5386 11911
9*375 69469
19336 *5003 II604 8894O
67337
18763 14639
11304 86563 65691
18309 1436a non
6387a
53861 40346 39798
3x860 15889
5*336 39070 38901
31x83 15383
50849 37936 38038 90534 Z4890
49400 36811 *7179 19884
144**
47988 357*6 *6354 19363
*3949
- r
X*
X* X3 X4
*3499 o* 96760
68714 48343 33693
13063
93544 66367 46648 3*48i
1*639 90426 64095 43009
3*3**
133*8 87<03 61895 434*3 30179
11839
84474 39765 41889 39086
1X44* 81635
57703 40406 38039
1x067 78885 SS7o6 3897*
*7009
10703 763X9
33774 37584 36033
*0330 73638
S*94 36*43 3307*
10008
71*3650094 34946 *4*3*
XS *3*63 **405 **377 30778 30006 X 139** 15310 14730 *4*7* 13633 X7 10363 99611 95740 92010 X* ( 0*0*^7*343 69483 667:6 64073 61517 X9 V-3^48096 46148 44*74 4*473 40741 4* 31671 30^359XY *9099 37888 36736 *1 *06 <8 10781 '180.12 18138 *7365 4* a 13346 1*769 122X5 11685 11176 4*3 0*0* 85399 816:7 78015 74S55 7**41 4*4 54**3 51685 49J50 47**7 44979
19363
13*** 88417
59039 39076
*8343 13611 84957 56694 37475
17849 13138 81624
544*8 35936
17180 1x663 78414 53338
34438
*6534 11313 753*4 50133 33037
33609 16624 10689 68069
4*935
*4336 159x3 10331
65031
40980
*3507 15330
97736 63133 391*0
33518 1457S
93447 59340 373**
31569 *3948
89337 56075 3S6i3
4*5 33977 3*4*4 30910 39493 38137 *6833 *3377 34386 *3*49 33163 4*6. *11*5 *o*33 19187 18183- 17430 16597 *5810 15060 14344 13660 4*7 13008 11386 **79* 11336 X0686 10171 96796 92113 87648 83391 4*8 o-o* 79333 75465 7*779 68367 64930 61731 58693 35799 53043 50418 4*9 479** 45538 43*7* 4***5 J9061 37*07 35*47 33476 3*79* 30190
45
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