|
Items in cart [4] |
Questions? Call 888-624-8373 |
| Copyright © 2009. National Academy of Sciences. All rights reserved. Terms of Use and Privacy Statement |
Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter.
Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.
OCR for page 16
~ ntroduction
Asbestos-associated diseases generally have been related to
occupational exposures, such as those experienced by some miners,
insulators, and factory workers (Doll, 1955; Gloyne, 1935, 1951;
Merewether, 1930; Selikoff, 1979; Selikoff et al., 1964; Wagner et al.,
1960) . Recent ly, however, there has been concern that exposure s to
asbestos and related fibers may present a health hazard to the general
public. Asbestos has been widely used in the United States for building
materials and in other applications. Consequently, there is exposure to
asbestos from many possible sources--in some schools and other public and
private buildings, in ambient air, 1 and in drinking water (National
Research Council, 1983; Sebastien et al., 1982; U.S. Environmental
Protec Lion Agency, 1980~.
Because asbestos and other asbestiform fibers2 appear to be
ubiquitous, virtually everybody is exposed to some extent. During
autopsy, asbestos fibers have been detected in the lungs of most urban
residents studied (Churg and Warnock, 1977; Langer et al., 1971; Pooley
et al., 1970; Wagner et al., 1982~. However, reported concentrations of
asbestos in urban air are usually considerably below the current U.S.
Occupational standard of 2 fibers/cm3.
Exposure of the public is particularly worrisome because the
populations involved are large and include unhealthy persons. Moreover,
exposure may begin in childhood, leaving a longer time for development of
adverse effects. Furthermore, asbestos may enhance the carcinogenic
effects of other materials. There is little information about the health
effects of most nonoccupational exposures to these fibers.
Despite ninny epidemiological studies of workers and experimental
studies on animals, questions remain about which properties of asbestos
are responsible for the adverse health effects and which conditions of
Ambient air is outside air to which the public is exposed (U.S.
Environmen~cal Protec t ion Agency, 1982b) .
2These include asbestos and other fibers with some of the same physical
propert ie s as asbe s tos .
16
OCR for page 17
17
exposure are most likely to lead to such effects. Certain other natural
mineral fibers, as well as man-mate mineral fibers sometimes used as
substitutes for asbestos and for other purposes, might have similar
deleterious effects (Artvinli and Baris, 1983; Stanton, 1974; World
Health Organization, 1983~.
The term "asbestos" refers to the fibrous form of several specific
silicate minerals that have been used commerc ial ly. Because of it s high
tensile strength, flexibility, and resistance to heat and chemical
at t ack , asbe s to s i s used in many produc ts, including asbestos-cement
pipes, insulation, friction materials, and flooring and roofing tiles
(Suta and Levine, 1979~.
The consumption of asbestos in the United States has greatly
increased during this century (Selikoff and Lee, 1978) . Annual U. S.
consumption peaked at about 800, 000 metric tons in 1973 and 1974, but in
1982 it dropped to 250,000 metric tons, or about 6: of world production
(U. S. Bureau of Mines, 1978, 1983) . Figure 1-1 shows U. S. asbestos
consumption by year since 1890 and cumulative consumption since l90S.
The millions of tons of asbestos already in place provide an ongoing
potential hazard to workers and the public.
The most serious health effects associated with exposure to asbestos
are lung cancer, mesothelioma (an almost invariably fatal form of
cancer), and asbestosis (a noncancerous but debilitating and sometimes
fatal disease). In addition, other nonmalignant lung changes have been
documented. Appendix A describes the chronology of the major observa-
tions documenting the relationship between asbestos exposure and disease.
Persons exposed to asbestos nonoccupationally can be at increased
risk of contracting these asbestos-associated diseases. In one of the
first studies linking asbestos exposure and mesothelioma, the disease was
found among residents of a mining area in South Africa. These subjects
had presumably inhaled the material in the surrounding air (Wagner et
al., 1960~. In another study, persons living in households with asbestos
factory workers in New Jersey were reported to be at increased risk of
asbestos-associated disease (Anderson et al., 1919~.
The diseases usually become evident clinically 20 to 40 years after
initial exposure, and may occur even in the absence of continued
exposure. Thus, many current cases of diseases assoc fated with asbestos
exposure are primarily the result of occupational exposures that the
individuals experienced many years ago. It has been est imated that up to
several hundred thousand excess deaths could result over the next few
decades from such exposures already experienced (Hogan and Hoel, 1981;
Nicholson et al., 1982; Walker et al., 1983~. Results of current
exposures would be manifested as disease in the future.
Because of the long latent period, it is difficult to reconstruct
exposure histories. Moreover, variations in particle size and in other
OCR for page 18
800,000
200,000
18
out 1 1 1 1 1 1 1 1
1890
~1
J
1910 19 ~i950 1970 19
YEAR
FIGURE 1-]A. Annual U. S. consumption of asbestos from 1890 to 1982.
4x107
o
. _
C,
E 3x107
o
In
o
o 2x 1 of
In
lxlO'
o
/
~ _
1~ 1 1
1900 1920
-
1 1 1 1 1 , ,1
t 940 1960 1 9B0 2000
YEAR
FIGURE 1-lB. Cumulative U.S. consumption of asbestos from 1905 to 1982
Based on data from U.S. Bureau of Mines, 1973, 197B, 1983.
J
i
l
?
1
l
·1
OCR for page 19
\
19
properties of asbestiform fibers may lead to different degrees of health
risk from apparently similar exposure. The effects of exposure to the
fibers may also be modified by other factors, such as smoking.
CONCURRENT NATIONAL RESEARCH COUNCIL AND GOVERNMENT ACTIVITIES
-
RELATED TO ASBESTOS
While this committee carried out its task, numerous other efforts
were under way to coordinate government activities and to summarize and
interpret findings concerning the health effects of asbestos. The U.S.
Environmental Protection Agency (1982a, 1983) issued reporting require-
ments related to asbestos in schools and reaffirmed its interest in
limiting the amount of asbestos used in certain applications. In 1983
the EPA, the Occupational Safety and Health Association (OS~A), and the
Consumer Product Safety Commission (CPSC) formed an interagency task
force on asbestos to coordinate information-gathering and regulatory
efforts concerning asbestos among the three agencies. For example,
OSHA has for several years considered revising the permissible exposure
limit for asbestos in the workplace. In 1976 the standard became
2 fibers/cm3. An asbestos fiber for counting purposes means a
particulate that has a physical dimension longer than 5 Am and a length-
to-diameter ratio of 3:1 or greater (U.S. National Institute for
Occupational Safety and Health, 1977, 1980~. In early November 1983,
OSHA issued an emergency temporary standard lowering the permissible
exposure limit to 0.5 fibers/cm3 (U.S. Occupational Safety and Health
Administration, 1983), but a stay on the temporary standard was granted
later in the month.
Asbestos as a health hazard was considered by the Chronic Hazard
Advisory Panel (CHAP) on Asbestos, which was formed in January 1983 by
the CPSC (Consumer Product Safety Act, 1981; U.S. Consumer Product Safety
Commission, 1982, 1983~. The panel was composed of persons nominated by
the National Academy of Sciences. Its major purpose was to provide
advice to CPSC on the risks of cancer associated with exposure to
asbestos. The National Research Council (NRC) has also engaged in
several activities related to asbestos. One was an analysis of data
related to asbestos in drinking water, which was part of a study
conducted by the NRC Safe Drinking Water Committee (National Research
Council, 1983~. The Committee on Nonoccupational Health Risks of
Asbestiform Fibers was able to draw upon the findings of the CHAP and NRC
reports and on other draft documents.
Another NRC activity is an ongoing study to identify and solve
problems related to asbestos exposure in federal buildings. This report
is being prepared by the Federal Construction Council Consulting
Committee on Asbestos under~the NRC Advisory Board on the Built
Environment (National Research Council, in press).
:&
OCR for page 20
20
Tan COMMITTEE'S APPROACH
To study the health effects of nonoccupational exposure to
asbestiform fibers, this committee took as its overview a "chain of
events" depicted in Figure 1-2. Thin figure shows that fibers may occur
naturally or be synthesized and that exposure of humans may result from
either commercial or environmental "flows." These human exposures may
then lead to biological reactions and adverse health effects.
While recognizing the difficulties involved in laterpreting data
related to health effects of asbestiform fibers, the committee considered
the following questions:
1. What are the major sources of nonoccupational exposure to
asbestiform fibers, and how great are such exposures?
2. Which properties of the fibers seem to be most closely associated
with adverse health outcomes? These properties may include length,
diameter, chemistry, strength, durability, mans, and surface
characterlatica.
3. Is it possible to distinguish different levels of carcinogenic
and fibrogenic risks among the different types of asbestos fibers? The
question is difficult to address by either epidemiological or laboratory
studies, because virtually al1 samples of fibers contain a range of fiber
sizes and other fiber characteristics may differ among the various
studies. Thus, it in difficult to relate observed effects to Specific
types of particles.
4. To what extent can the data on occupational exposures be used to
develop risk estimates for the general public?
In order to respond to its charge from EPA, the committee considered
various routes of exposure, but placed emphasis on the inhalation route.
To elucidate the relevant properties of the fibers responsible for the
adverse health effects, it evaluated physical, epidemiological, and
toxicological data related to asbestiform fibers. It also estimated the
health risk for certain populations under various assumptions of
exposure. Although many of the data reviewed in this study concern
asbestos, the committee has drawn conclusions that encompass other
fibrous materials as well.
The committee has not carried out an exhaustive review of the
literature, but has concentrated instead on those data that are most
relevant to the charge. It found many excellent reviews and collections
of articles related to asbestos and other fibrous materials that have
appeared in recent years. Among the documents that were most useful
during the course of this study were those prepared by Selikoff and Lee
(1978), Wagner (1980), Craighead and Mosaman (1982), Walton (1982), and
papers from a conference on biological effects of man-made mineral
!
l
OCR for page 21
o
E
o
i
.
~'
21
C,
-
"C
_
_ ._
~ _
~ o
_ _
T
, ~
o o
.
.
~ lU g
E - ~
, _ o
°m
· ~
_
_
2m 0
._ C ~ _ ·n
~ C C~ ~ ~
C O g 0
° &o
· ~
T
C
o
.C ~ ~
{,, - , o
o
,:
~C ·O
C ~o ~
~ ~ . ~
c~ C )
o ~
o o ~ o
.
.
-
cO
.
.
g
.
C~
C
Ec
o
_
._
C
LU o
D ~
. - ~
0
E
o
· -
~ 3
cn
0
3
o
-
,1
C)
C) ~
o
C)
:^
C~
E
-
o
s~
o
o
. -
3 0
o
_
eS
~ ID . -
S
~ CL
oC ~
_
- o
CI: l
o
-
E
..g
o ~
. -
. -
-
s
C 0
x
0
0 ~
. - ~
V
C
E
o
. -
C
h
os
~ ~ 3
=,c o
_
1
v
.
. ..c
3
o
0
0
o'
o
CL
X
~n ~
:'
X
o
D
o
v
-
OCR for page 22
22
fibers, which was held in Copenhagen in April 1982. The proceedings of
that conference have been Prized by the World Health Organization
(1983).
The succession of chapters in this report reflects a logical sequence
for pursuing this study. First, the committee defined the kinds of
materials it was conaldering and described some of their properties. It
then assessed exposure to these materials. Its next step was to consider
the various ways of determining the amounts of fibers both in the
workplace and in the ambient environment and to evaluate epidemiological
and laboratory data. Finally, it integrated data from exposure,
epidemiological and laboratory studies in order to make quantitative and
comparative risk assessments.
REFERENCES
Anderson, H. A., R. Lilis, S. M. Da''m, and I. J. Selikoff . 1979.
Asbestosis among household contacts of asbestos factory workers.
Ann. N.Y. Acad. Sci. 330: 387-399.
Artvinli, M., and Y. I. Barls. 1982. Environmental fiber-induced
pleuro-pulmonary diseases in an Ar~atoliar~ village: An epidemiologic
study. Arch. Environ. Health 37:177-181.
Churg, A., arid M. L. Warnock. 1977. Correlation of quantitative asbestos
body counts and occupation in urban patients. Arch. Pathol. Lab.
Med . 101: 629-634.
Consumer Product Safety Act. 1981. Section 1206 of the Omnibus Budget
Reconciliation Act of 1981 (P.L. 97-35; 15 U.S.C. 2077, as amended).
Craighead , J . E., and B . T . Monaman. 1982 . The pathogenesis of
asbestos-associated diseases. N. EngI. J. Med. 306: ~ 446-1455.
Doll, R. 1955. Mortality from lung cancer in asbestos workers. Br. J.
Ind. Med. 12:81-86.
Gloyne, S. R. 1935. Two cases of squamous carcinoma of the lung
occurring in asbestosis. Tubercle 14:445-451.
Glove, S. R. 1951. Paeumoconioala. A historical survey of
necropay material in 1205 cases. Lancet l:~10-~14.
Hogan, M. D., and D. G. Hoel. 1981. Estimated cancer risk associated
with occupational asbestos exposure. Risk Analysis I: 67-79.
Langer, A. M., V. Baden, E. C. Hammond, and I. J. Selikoff. 1971.
Inorganic fibers including chrysotile in lunge at autopsy:
Preliminary report. Pp. 683-694 in W. H. Walton, ed. Inhaled
Particles III. The Gresham Press, Surrey.
Levine, R. J., ed. 1978. Asbestos: An Information Resource. U.S.
Department of Health, Education, and Welfare, Public Health Service,
National Institutes of Health.
Merewether, E. R. A. 1930. The occurrence of pulmonary fibrosis and
other pulmonary affections in asbestos workers. J. Ind. Byg.
12:198-222, 239-257.
OCR for page 23
23
National Research Council. 1983. Drinking Water and Health. Vol. 5.
A report of the Safe Drinking Water Committee, Commission on Life
Sciences. National Academy Press, Washington, D.C.
National Research Council. In press. Identifying and solving asbestos
problems in existing federal buildings. Draft report of the Federal
Construction Council Consulting Committee on Asbestos. National
Academy Pres a, Washington, D . C.
Nicholson, W. J., G. Perkel, and ~ . J . Selikoff . 1982. Occupational
exposure to asbestos: Population at risk and projected mortality--
1980-2030. Am. J. Ind. teed. 3: 259-311.
Pooley , F. D., P. D. Oldham, U. Chang-Hyun, and J. C. Wagner. 1970.
The detection of asbestos in tissues. Pp. 108-116 in H. A. Shapiro,
ed . Pneumoconiosi ~ . Proceedings of the International Conference in
Johannesburg. Oxford University Press, Cape Town.
Sebastien, P., J. BigDon, and M. Martin. 1982. Indoor airborne
asbestos pollution: From the ceiling and the floor. Science 216:
1410-1413.
Seilkoff, I. J. 1979. Mortality experience of insulation workers in
the United Stances and Canada, 1943-1976. Ken. N.Y. Acad. Sci . 330:
91-116.
Selikoff, I. J., and D. K. Lee. 1978. Asbestos and Disease. Academic
Press, New York. 549 pp.
Selikoff, I. J., J. Churg, and E. C. Hammond. 1964. Asbestos exposure
and neoplasia. J. Am. Med . Assoc . 188: 22-26.
Stanton, M. F. 1974. Fiber carcinogenesis : Is asbestos the only
hazard? J. Natl. Cancer Inst . 52: 633034.
Suta, B. E. , and R. J. Levine. 1979. Non-occupational asbestos
emissions and exposures. Pp. 171-205 in L. Michaels and S. S.
Chissick, eds. Asbestos. Properties, Applications, and Hazards.
Vol. 1. John Wiley & Sons, New York.
U.S. Bureau of Mines. 1973. Minerals Yearbook 1972. Bureau of Mines,
Department of the interior, Washington, D.C.
U.S. Bureau of Mines. 1978. Asbestos. Minerals Yearbook 1977. Bureau
of Mines, Department of Interior, Washington, D.C.
U.S. Bureau of Mines. 1983. Asbestos. Preprint from the 1982 Minerals
Yearbook. Bureau of Mines, Department of the Interior, Washington,
D.C.
U.S. Consumer Product Safety Commission. 1982. Chronic hazard advisory
panel on asbestos; invitation to submit suggestions for Scientists to
serve as members. Fed. Regist. 47:17323-17324.
U.S. Consumer Product Safety Commission. 1983. Report by the Chronic
Hazard Advisory Panel on Asbestos. Consumer Product Safety
Commission, Washington, D.C.
U.S. Environmental Protection Agency. 1980. Asbestos-Containing
Materials in Schools. Health Effects and Magnitude of Exposure.
Support document for proposed ~
materials in School buildings. Office of Pesticides and Toxic
Substances, Environmental Protection Agency, Washington, D.C.
r'~1 A 6 On friable asbestos-containing
OCR for page 24
24
U.S. Environmental Protection Agency.
1982a. Asbestos; friable
materials in schools; identification and
asbestos-containing
notification. Fed. Regist. 47:23360-23389.
U.S. Environmental Protection Agency. 1982b.
National primary and
secondary ambient air quality standards. Definitions. Code of
Federal Regulations, Title 21, Part 50.1.
U.S. Environmental Protection Agency. 1983. Rules restricting the
commercial and industrial use of asbestos fibers. Fed. Regist.
48:47880.
U.S. National Institute for Occupational Safety and Health. 1977.
Asbestos Fibers in Air. NIOSH Manual of Analytical Methods. Second
Edition. Vol. 1. National Institute for Occupational Safety and
Health, Cincinnati.
U.S. National Institute for Occupational Safety and Health. 1980.
Workplace Exposure to Asbestos. NIOSH-OSHA Asbestos Work Group.
NIOSH Pub. No. 81-103. National Institute for Occupational Safety
and Health, Cincinnati.
U.S. Occupational Safety and Health Administration, 1983. Occupational
exposure to asbestos: Emergency temporary standard. Fed. Regist.
48:51086-51140.
Wagner, J. C., ed. 1980. Biological Effects of Mineral Fibres.
Vola. 1 and 2. IARC Scientific Pub. No. 30. International Agency
for Research on Cancer, Lyon. 1001 pp.
Wagner, J. C., C. A. Sleggs, and P. Marchand. 1960. Diffuse pleural
mesothelioma and asbestos exposure in the North Western Cape
Province. Br. J. Ind. Med. 17:260-271.
Wagner, J. C G. Berry, and F. D. Pooley. 1982. ' -' - -'
Mesothelioma and
asbestos type in asbestos textile workers: A study of lung
contents. Br. Med. J. 285:603-606.
Walke r, A. M., J. E . Laughlin, E. R . Priedlande r, K. J . Rothman, and
N. A. Dreyer. 1983. Projectlons of asbestos-related disease
1980-2009. J. Occup. Med. 25:409-425.
Walton, W. H. 1982. The nature, hazards and assessment of occupational
exposure to airborne asbestos dust: A review. Area. Occup. Hyg.
25: Il7-247.
World Health Organization. 1983. Biological Ef fects of Man-Made Mineral
Fibers. Report on a WHO/lARC Meeting, Copenhagen, April 20-22,
1982. EURO Reports and Studies No. 81. World Health Organization,
Copenhagen.
Representative terms from entire chapter:
product safety
