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Sisal,
an Alternative to Asbestos
Mario
Osava
RIO DE JANEIRO, (IPS) - Sisal, a
vegetable fibre, could serve as an
alternative to asbestos in Brazil, the
world's fourth- largest producer of
the hazardous mineral.
Romildo Toledo, a researcher with the
graduate programme in engineering at
the Federal University of Rio de
Janeiro, believes sisal is an
economically viable alternative to
asbestos.
When the tiny asbestos fibres enter
workers' lungs, they frequently cause
health disorders like lung cancer,
asbestosis (a stiffening of the lung),
or mesthelioma (fatal tumours). Even
family members are at risk, if workers
bring home their work clothing.
Evidence of the health risks posed by
asbestos, especially to workers who
handle it in the mining, construction
and other industries, has led it to be
banned in 36 countries, mainly in
Europe, according to the Brazilian
Association of Workers Exposed to
Asbestos (ABREA), a group that was
founded in 1995.
Toledo and his research team have been
working with sisal, a strong durable
white fibre used especially for
cordage, twine and bags for
agriculture. Sisal comes from the
agave plant, which is grown in
Brazil's impoverished semi-arid
northeast, on land threatened by
desertification due to lack of
vegetation cover.
Reverting the current decline of that
crop would also provide environmental
and social as well as economic
benefits in that region, said Toledo
in an interview with IPS.
Brazil produces 209,000 tons of
asbestos a year, one-third of which is
exported to some 25 different
countries, mainly in Asia and Latin
America, according to SAMA, the only
company authorised to mine asbestos in
Brazil.
This South American country is the
world's fourth largest producer,
accounting for one-tenth of all
asbestos used worldwide.
SAMA also reports that 90 percent of
the asbestos used in Brazil goes
towards the production of fibre-cement,
a low-cost material that is made up of
10 percent asbestos and is mainly used
to manufacture roofing materials and
water tanks.
Russia is the world's top producer of
asbestos, followed by Canada, which
has become the biggest exporter,
exporting 98 percent of its total
production of 585,000 tons a year,
reports ABREA.
At least 100,000 asbestos-related
deaths occur worldwide every year, a
figure that continues to grow, even in
countries that have banned the use of
the mineral, because the time between
diagnosis and original exposure to
asbestos is commonly 30 years or more,
according to the International Labour
Organisation (ILO).
More than 600,000 lawsuits demanding
reparations for victims of asbestos
exposure have already been filed in
the United States, a number that
experts say will double or even
triple. The statistics indicate that
around 27 million people in that
country were exposed to asbestos
between 1940 and 1979.
The use of asbestos was banned in the
southern Brazilian state of Sao Paulo
in 2001, a move that was expected to
bring about a drastic reduction in
asbestos use, of which Sao Paulo
accounts for 70 percent in this
country of 170 million, engineer
Fernanda Giannasi, the coordinator of
the Latin America-wide Virtual Citizen
Ban Asbestos Network, told IPS.
But three months ago there was a
''setback,'' said Giannasi, who is
also involved in ABREA, and is the
Labour Ministry official in charge of
inspecting factories that utilise
asbestos.
She explained that in May, Brazil's
supreme court ruled that the ban
passed by the Sao Paulo legislative
assembly, as well as a similar ban
adopted in the state of Mato Grosso do
Sul, were unconstitutional, on the
grounds that it was a question that
fell under federal, not state,
jurisdiction.
But the hazardous mineral, which is
used in some 3,000 industrial
products, continues to be mined and
utilised in Brazil, because neither
the central government nor the
national Congress have taken steps to
prohibit its use, despite the fact
that 2,500 victims of asbestos-related
ailments ''have already been
recognised and indemnified by the
asbestos industry,'' complained
Giannasi.
She admitted, however, that it is
difficult to find a substitute for
asbestos with the same level of
resistance to mechanical force, fire,
micro-organisms and chemical elements,
as well as its durability, flexibility
and effectiveness as a thermic and
acoustic insulating material.
The alternatives used so far, ranging
from plastics to wood fibres, are more
expensive and less effective, said
Giannasi.
For his part, Toledo at the Federal
University of Rio de Janeiro said the
big problem in coming up with a
vegetable fibre substitute is that
when they come into contact with
cement, fibres like sisal ''lose
resistance and become brittle with
time,'' which makes them less durable.
Nevertheless, sisal has begun to be
used in recent years as an
environmentally-friendly strengthening
agent to replace asbestos and
fibreglass, and has been found to work
well in the reinforcement of cement in
roofing tiles, for example.
The approach taken by Toledo's
research team to overcome the
shortcomings of sisal as an
asbestos-replacement material has been
to modify the cement, rather than
attempting to improve the sisal, as
other researchers have done.
The engineering team's research has
focused on the production of
''ecological concrete,'' in which
waste products like the ashes of the
burnt hulls of rice (the papery covers
removed in milling), sugar cane
bagasse, or the dust left after rocks
or ceramic are crushed are added to
the cement.
The waste products not only reduce the
cost of the cement while maintaining
the quality, but they replace lime, or
calcium hydroxide. Lime is the product
to which sisal reacts, which weakens
the cement, Toledo explained.
The lab tests carried out so far have
shown success in coming up with a mix
that is comparable to fibre-cement in
terms of durability and other
properties, at a significantly reduced
cost.
The next step, said Toledo, is to
perfect ''secondary properties'' like
impermeability, and to test the
product in large- scale industrial
applications.
But Emilio Alves Ferreira Junior, the
president of the National Commission
of Asbestos Workers, a network of
trade unionists, told IPS that the way
asbestos is handled today in Brazil no
longer poses a health risk to workers.
''A viable, healthy alternative will
be welcome,'' but only because it will
generate more jobs, he argued.
According to Ferreira, strict laws and
an agreement reached by trade unions
and companies in 2000 have led to
effective protection for workers,
through the creation of commissions
set up in every factory to enforce
safety regulations.
In Brazil's only asbestos mine,
located in Minaçú in the west-
central state of Goias, the tasks in
which exposure to asbestos is greatest
are now carried out by machines, said
Ferreira.
He also mentioned the problem of
employment. The Minaçú mine employs
1,800 workers, and the 23 factories
that manufacture products containing
asbestos provide 12,000 direct jobs.
But Giannasi does not believe in the
concepts of ''controlled use'' and
''zero health risk.'' She points out
that not even industrialised countries
have been able to avoid
asbestos-related illnesses and deaths,
and that working conditions in
developing countries are much more
precarious.
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