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Apply
strictly regulations aimed at preventing any exposure to known
cancercausing substances. Follow all health and safety instructions
on substances which may cause cancer. Follow advice of national
radiation protection offices.
The
prevention of exposure to occupational and environmental carcinogens
has followed the identification of a substantial number of
natural and man-made carcinogens, and has led to significant
reductions in cancer occurrence. The message in this item
of the code solicits responsible behaviour for individuals
in three respects:
1)
from those who have to provide timely and clear instructions,
primarily legislators and regulators who should adapt scientific
consensus evaluations into European Union law, and control
compliance with these regulations;
2)
from those who should follow these instructions and comply
with the laws to
protect the health of others, for instance,
managers, hygienists and doctors in industry; and
3)
from every citizen who in order to protect their own
health and the health of others, ought to pay heed
to the
presence of carcinogenic pollutants and follow instructions
and regulations aimed at mitigating or preventing exposure
to carcinogens
The
latter applies to a wide variety of circumstances such as
traffic restrictions within cities, restrictions on smoking,
use of personal safety devices and respecting validated procedures
in the workplace. Application of regulations is particularly
important in the working environment where carcinogens may
be found in higher concentrations than in the general environment.
The control of the prevalence and level of exposure to occupational
and environmental carcinogens through general preventive measures
has historically played a more important role in preventing
cancers than individual measures of protection.
The
cancers that have most frequently been associated with occupational
exposures are those of the lung, urinary bladder, mesothelioma,
larynx, leukaemia, angiosarcoma of the liver, nose and nasal
cavity and skin (non-melanoma). Several other neoplasms have
also been associated with occupational exposures but the evidence
is less strong. They include cancers of the oral cavity, nasopharynx,
oesophagus, stomach, colon and rectum, pancreas, breast, testis,
kidney, prostate, brain, bones, soft-tissue sarcoma, lymphomas
and multiple myeloma. Most known or suspected occupational
carcinogens have been evaluated by the
International Agency for Research on Cancer
(IARC Lyon, France). Actually, 29 chemical or physical agents,
groups of agents or mixtures that occur predominantly in the
workplace, have been classified as human carcinogens (Group
1 of the IARC classification). In the same Group 1, IARC has
classified 13 industrial processes or occupations, such as
the rubber industry, painters, etc. In European Union countries,
production or use of some of these chemicals has been banned
and are only of historical interest (e.g. mustard gas, 2-naphthylamine),
while some high-risk industries have stopped functioning (e.g.
‘Wismut’ uranium ore mining associated with exposure
to ionising radiation). Exposure to other carcinogens such
as metals and dioxins is still widespread.
Thirty-five
agents or industrial processes are classified as probably
carcinogenic to humans (Group 2A of the IARC). Many of the
agents in this group are still widely used, for example 1,3-
butadiene and formaldehyde. More than 200 agents, groups of
agents or exposure circumstances are classified as possibly
carcinogenic to humans (Group 2B) largely on the basis of
carcinogenicity data from animal experiments. It has been
estimated that in the early 1990s about 32 million workers
(23% of those employed) in the European Union were exposed
to carcinogenic agents at levels above background. Exposure
to these agents is still widespread but occurs mostly at low
levels. The more common occupational exposures are solar radiation,
passive smoking, crystalline silica, diesel exhaust, radon,
wood dust, benzene, asbestos, formaldehyde, polycyclic aromatic
hydrocarbons, chromium VI, cadmium and nickel compounds. Extensive
preventive measures in the workplace in recent decades have
resulted in the prevention of many cancers related to workplace
exposures. This has been well documented, for example for
occupational bladder cancer after the ban on the use of beta-naphthylamine
in the rubber and chemical industries. The delays in taking
protective measures, however, and the long latency for many
neoplasms will result, in certain instances, in a continuous
increase in the number of occupational cancers during the
coming years. An increasing number of mesothelioma cases due
to past occupational exposure to asbestos is expected in many
European Union countries for another 10–20 years, even
though asbestos has been banned in some European Union countries
since the early 1990s. The proportion of all cancers that
can be causally attributed to carcinogens in the occupational
environment and are therefore wholly or partially avoidable
through exposure control, remains difficult to quantify reliably.
An estimated 5% of cancers is attributable to the occupational
environment. This proportion depends on the variable prevalence
of the exposures by geographical areas, gender, socioeconomic
status and periods of time, as well as on the concurrent prevalence
of other dominant cancer causing factors, particularly tobacco
smoking. Furthermore, the effect of specific occupational
carcinogens, such as aromatic amines or polycyclic aromatic
hydrocarbons, is also mediated by genetic factors, such as
genetic polymorphisms of the NAT2 or GSTM1 genes. The distribution
of these polymorphisms within the populations of the European
Union is fairly uniform and genetic factors probably do not
determine differences in the proportion of occupational cancers
between populations in European Union countries.
Environmental
exposures usually refer to exposures of the general population
that cannot be directly controlled by the individual. They
include air-pollution, drinking water contaminants, passive
smoking, radon in buildings, exposure to solar radiation,
food contaminants such as pesticide residues, dioxins or environmental
estrogens, chemicals from industrial emissions, and others.
Exposure may be widespread, as is the case for air pollution,
or could be restricted, as would be the case of populations
living in the vicinity of a contaminating industry. These
exposures have been associated with a variety of neoplasms,
including cancers of the lung, urinary bladder, leukaemia
and skin. The impact of several environmental carcinogenic
exposures, such as arsenic in drinking water, has not been
quantified, though exposure to arsenic is likely to affect
only limited population groups. Air pollutants, such as fine
particles, have been associated in several studies with a
small increased risk of lung cancer even at current low-level
urban exposure levels. The evidence on other exposures that
are widespread, such as disinfection by-products in drinking
water, is still inconclusive. Agents in the general environment
to which a large number of subjects are exposed for long periods,
such as passive smoking or air-pollution, although increasing
only modestly the relative risk for certain cancers may be
at the origin of several thousand cases per year in the European
Union.
It
is essential that for any agent liable to present a risk,
the nature, degree and duration of such risk must be determined
in order to define what measures need to be taken to prevent
or reduce the exposure. Among these measures, suitable operating
procedures and methods are of utmost importance. Instructions
to be followed may take the form of quantitative control limits
of exposure, derived empirically or through formal procedures,
which still leaves much to be desired. The specification of
a quantitative control limit of exposure in the general and
occupational environment combines two elements: the quantitative
estimate of the risk associated with a given level of exposure
and the level of risk regarded as socially "acceptable",
with consideration of the technical feasibility, and human
and economic costs of various degrees of control.
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