To: Directors of Environmental Health/ Chief Environmental Health Officers of London, Metropolitan, District and Unitary Authorities and Chief Executives of County Councils.

For the attention of: Environmental Services / Trading Standards / Fire Authorities / Other

This circular gives advice to local authority enforcement officers

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GUIDANCE ON THE USE OF SEPIOLITE

INTRODUCTION

1 This circular gives information on the use of sepiolite which is a hydrated magnesium silicate mineral occurring naturally either in a fibrous metamorphic form or in a sedimentary form as a clay.

BACKGROUND

2 Approximately 40,000 tonnes per annum of sepiolite is imported from Spain by Steetley Minerals Limited, Nottinghamshire and Lawrence Industries, Surrey. Spanish sepiolite is of the sedimentary clay type and is in the form of white granules with less than 1 % below 550 micrometres diameter. Small quantities of sepiolite have been imported from Turkey and Africa, whilst American sepiolite is imported as cat litter.

3 Sepiolite is commonly used as an oil absorbent on workshops floors. It can also be used as a filler in paints, as a binder for molecular sieves, and as a free flow agent in agricultural pesticide manufacture.

SEPIOLITE FIBRES

4 Few sepiolite fibres in the size range of the asbestos fibre definition (i.e. length greater than 5 micrometres, breadth less than 3 micrometres and length to breadth ratio of at least 3: 1) have been found, even when samples have been dry ground in a pestle and mortar or ultrasonically vibrated. Examination of wet or dry ground sepiolite by transmission electron microscopy (which can resolve fibre bundles) showed fibres of 0.02 to 0.08 micrometres diameter with lengths up to 2.5 micrometres; no single fibres greater than 8 micrometres in length have been observed in ground material. However, ultrasonically vibrated material can give rise to fibre of less than 0.25 micrometres diameter and length greater than 8 micrometres.

5 The effects on health from inhalation of sepiolite or other non-asbestos fibres is uncertain. Animal experiments indicate that fibres less than 0.25 micrometres in diameter and greater than 8 micrometres in length are most likely to induce tumours by artificial implantation. Fibres of 0.25 to 1.5 micrometres in diameter and greater than 4 micrometres in length also induce tumours in animals but to a lesser extent. Fibres outside these size ranges exhibit a low correlation with tumours. It has yet to be demonstrated that the inhalation of sepiolite fibres is harmful to humans. Suppliers of sepiolite should classify it as necessary under the Chemicals (Hazard Information and Packaging for Supply) Regulations 1994, as amended (CHIP).

6 Information available suggests that granular sepiolite, when used as an oil-absorbent material, presents little health hazard. If granular sepiolite is subjected to ultrasonic vibration, e.g. as in the paint industry, the material could break down and form numerous fibres in a size range which is potentially harmful to health.

7 Sepiolite is not assigned an Occupational Exposure Standard or Maximum Exposure Limit under the Control of Substances Hazardous to Health Regulations 1999 (COSHH). If airborne concentrations of sepiolite are substantial, that is above 10 mg/m³ 8- hr Time Weighted Average (TWA) of total inhalable dust or 5mg/m³ 8-hr TWA respirable dust, sepiolite will come within scope of COSHH, and a risk assessment and consequent exposure control are required. Normally, the most straightforward way to achieve this will be to reduce the dust concentrations as far as is reasonably practicable.

ENFORCEMENT APPROACH

8 It is suggested that if local authority enforcement officers find any use of sepiolite not mentioned in para 3, the information should be forwarded to the ELO in their relevant area.

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