Silica feared as 'next asbestos'

[Guest guest]

ABSTRACT: Silicosis and other occupational diseases

are still important even in the most developed

countries. In fact, at present, silica exposure may be

a risk factor for human health not only for workers

but also for consumers. Furthermore, this exposure is

associated with many other different disorders besides

pulmonary silicosis, such as progressive systemic

sclerosis, systemic lupus erythematosus, rheumatoid

arthritis, dermatomyositis, glomerulonephritis and

vasculitis. The relationships between these

silica-related diseases need to be clarified, but

pathogenic responses to silica are likely to be

mediated by interaction of silica particles with the

immune system, mainly by activation of macrophages. As

regards renal pathology, there is no single specific

clinical or laboratory finding of silica-induced

nephropathy: renal involvement may occur as a toxic

effect or in a context of autoimmune disease, and

silica damage may act as an additive factor on an

existing, well-established renal disease. An

occupational history must be obtained for all renal

patients, checking particularly for exposure to

silica, heavy metals, and solvents.

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Silica feared as 'next asbestos'

By Yvette Essen (Filed: 20/09/2004)

Silica sand, which is often turned into a gel and put

into handbags and electronic goods to soak up

moisture, has become the latest substance to join a

list of toxic products worrying underwriters.

Aon, the second-largest insurance broker, said

individuals extracting silica or working on

manufacturing sites may be overexposed to the product,

which could lead to silicosis - " a disabling,

non-reversible and sometimes fatal lung disease " .

Other problems can include lung cancer, pulmonary

tuberculosis, airway diseases, autoimmune disorders

and chronic renal disease.

The broker has added silica to its toxic substances

database, which lists materials troubling the

insurance and reinsurance industry. Asbestos and

tobacco are also on the list, as is toxic mould - a

fungus that grows on walls and carpets, and can lead

to respiratory problems. Aon said the potential for

class action is " possible " .

While there has been no medical evidence of a link

between silica gel and silicosis, reinsurers are

investigating whether exposure to silica sand could

lead to numerous insurance claims.

Mark Hewett, deputy chairman of Guy Carpenter, the

world's largest

reinsurance broker, said his company is conducting

research into

silica. He said: " It is a common product in a natural

environment but it starts to get hazardous if it is

cut and the dust particles get in the air. The big

question is, is it the next asbestos? We think it is

probably not but it raises a number of similar

issues. "

Silica is used in the stone masonry business, for

glass production and pool filter sand. Aon says ground

silica is " ideal for plastics and rubber, polishes and

cleansers, glassfibre and precision castings. "

Fine-ground silica is a high-quality filler used in

paints and

coatings.

2 July 2002: Insurers shun 'new asbestos' [toxic

mould]

INTRODUCTION WHAT IS SILICONE?

Silicones are a family of chemical compounds. They are

made from

silicon, a naturally occurring element found in sand,

quartz, and

rock. Next to oxygen, silicon is the most common

element in the

earth's crust, and becomes silicone when it is

combined with oxygen, carbon, and hydrogen. Depending

on the arrangement of the molecules, silicones can be

manufactured in a variety of forms, including oils,

gels, and solids.1

CONSUMER AND MEDICAL PRODUCTS

Silicones have been part of the consumer industry for

over 50 years. Because they can be manufactured in

various ways, silicones appear in a wide variety of

products that most of us use everyday. Hairsprays,

suntan lotions, and moisturizing creams are just some

of the consumer products that contain one form of

silicone called dimethicone. The applications of

silicone, whether used as an oil, gel, or solid, are

equally extensive in the medical field. For example,

the lubricating qualities of silicones make them ideal

for coating surgical needles and suture thread, as

well as the inside of syringes and bottles used for

the storage of blood and intravenous medicines.

Protective silicone coatings have also been used in

pacemakers and heart valves. Other medical devices

utilizing silicones include: artificial joints,

catheters, drainage systems, facial implants, tissue

expanders, and breast implants. Silicone products have

been shown to be biocompatible, reliable, flexible,

and easy to sterilize, making them an ideal choice for

both implantable and non-implantable medical devices.