Health and Safety Aspects
→ Advice to Users
→Design and Specification
→Results of Testing
→Summary
→References

Advice to Users

Extensive tests have been conducted on Saffil alumina fibre and all results lead to the conclusion that Saffil fibre is unlikely to have any significant toxic effect. Nevertheless, we recommend that atmospheric exposure be controlled to a Maximum Exposure Limit (MEL) of 5 mg/m 3 total dust or 2 fibres/ml, whichever is the more stringent, each 8-hour Time Weighted Average, according to the COSHH (Amendment) Regulations 1990. (Reference 1). Experience shows that the gravimetric standard has proved the more appropriate for operations involving Saffil fibres. If it is necessary to apply the fibre count method then fibre clumping on the filter may be a problem.

Under the COSHH Regulations for substances with an MEL, exposures should not exceed the MEL and should be reduced so far as is reasonably practical below the MEL. In our experience, even very severe handling of Saffil fibre products only transiently produces dust concentrations exceeding 5 mg/m3 but, where this does occur, we recommend that ventilation be provided or effective dust masks be worn.

Practical experience has shown that 'Saffil' fibre may cause temporary irritation of the skin, nose and throat. It is recommended therefore that gloves be worn by operators handling the fibres repeatedly, that clothing should be loose around the neck and wrists and that precautions be taken (as described in the previous paragraph) to avoid breathing dusts. After handling, exposed skin areas should be washed with water and work clothing should be washed separately. For further advice on handling 'Saffil' fibre see Reference 2.

Design and Specification

Any insoluble fibrous material may have the potential to induce adverse health effects. 'Saffil' fibre has been carefully designed and is produced to a specification intended to minimise any biological activity. The basic material (alumina) does not produce fibrosis in powder form and fibre diameter is carefully controlled within a narrow range to minimise the number of sub micron fibres (considered to have the potential to induce fibrosis and mesothelioma) and also to minimise the proportion of fibres which are respirable (likely to penetrate into the depths of the lung). At the same time the proportion of fibres greater than 5 microns diameter is minimised to reduce its irritant potential.

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Results of Testing

Saffil fibre produced to the above specification has been subjected to an extensive series of animal and other tests to verify the design assumptions and to determine any toxic potential. These tests are summarised below:

1 Intraperitoneal Injection and Cytotoxicity Tests
Saffil fibres were injected into the peritoneal (abdominal) cavity of rats and the animals maintained for observation for up to one year. The reaction to Saffil fibre was quite distinct from the fibrotic reaction produced by asbestos and indicates a lack of fibrogenic potential. The results of two in vitro tests for fibrogenic potential were also negative.

2 Intratracheal Injection
Saffil fibres were injected into the lungs of rats via the windpipe and the animals maintained for the remainder of their lifespan. No signs of fibrosis or cancer associated with the treatment were seen, although rats injected with asbestos as a positive control showed a number of cases of lung fibrosis.

3 Intrapleural Injection
Saffil fibres were injected directly into the pleural space of rats (the space between the rib cage and the lung tissue) and the animals maintained for the remainder of their lifespan. Two studies on very similar Saffil fibre samples showed no signs of pleural fibrosis or mesothelioma, while asbestos treated control rats showed the expected incidence of both. This extremely severe test (in which false negatives are unknown) indicates that 'Saffil' fibre probably lacks one or more of the fundamental characteristics necessary for mesothelioma induction, as well as providing further evidence of the absence of fibrogenic potential.

4 Inhalation
Rats were exposed to atmospheres containing the maximum achievable levels of 'Saffil' fibre for seven hours/day, five days/week for 18 months and then maintained for the remainder of their lifespan. No lung fibrosis or lung cancer were seen although asbestos treated control rats showed the expected incidence of both. The minimal lung response seen in Saffil fibre treated rats was typical of a 'nuisance particulate' (ACGIH definition (3)). Extensive investigations showed no other treatment related effects. This study provides confirmation by the route of exposure most relevant to man of 'Saffil' fibre's lack of toxic potential.

5 Ingestion
Feeding trials on rats have been conducted with Saffil fibres and these have shown no evidence of fibre penetration of the gut or accumulation of fibre in any part of the body. A lifetime feeding study has produced no evidence of any effects due to Saffil fibre at levels up to 2.5% in the diet.

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Summary

Saffil fibre is designed and produced to minimise biological effects and the extensive series of tests described above confirms that exposure to Saffil fibre is unlikely to have any significant toxic effect in the lung. It can be irritant to the skin, nose and throat.

References

Control of Substances Hazardous to Health (Amendment) Regulations 1990. (Effective 01.01.91).
Code of Practice : Working with Saffil Alumina Fibre.
American Conference of Governmental Industrial Hygienists (ACGIH). Threshold Limit Values and Biological Exposure Indices for 1990-91.

The contents of this note are given in good faith but without warranty and the user must satisfy himself that the product is entirely suitable for his purpose. Freedom from patent rights must not be assumed.

SAFFIL LTD
Pilkington-Sullivan Site
Tanhouse Lane
Widnes
Cheshire
WA8 0RY
United Kingdom
Tel: +44 (0)151 422 6700
Fax: +44 (0)151 422 6701

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