Hazardous Chemical Information System (HCIS)

Graphite (all forms except fibres) (respirable dust)

No standard should be applied without reference to Guidance on the interpretation of Workplace exposure standards for airborne contaminants.

Documentation Notice

Note: This exposure standard is based on the ACGIH TLVs list. Thevalue chosen has been changed to reflect the current Australian coal duststandard of 3 mg/m³ (respirable dust). Readers should refer to therelevant ACGIH documentation, keeping in mind that the Australian coal duststandard is 3 mg/m³, whereas in the United States of America it is2 mg/m³.

1. BACKGROUND INFORMATION

Graphite is a crystalline form of carbon. Natural graphite resulting fromthe metamorphosis of coal usually contains a variety of mineral impurities.Synthetic graphite is manufactured from a mixture of coal or petroleum coke,a binder (usually coal tar pitch) and sometimes anthracite coal. Graphite isrelatively inert chemically and has good refractory properties. Thetwo forms of graphite may be blended with certain minerals or petroleumproduct additives. Exposure to graphite may result from its use as arefractory, in lubricants as electrodes, as filters in dry cells and ascarbon brushes in electric motors and equipment.

2. ANIMAL AND HUMAN STUDIES

The American Conference of Governmental Industrial Hygienists (ACGIH)documentation ⁽¹⁾ contains several reports ofthe similarity of pneumoconiosis found in synthetic and natural graphiteworkers compared with that seen in coal miners. Both animal and humanevidence also suggest similar fibrogenic activity when crystalline silica isalso present. It is suggested that occupational history is necessary todistinguish graphite workers' and coal miners' pneumoconioses.

Based on this similarity the ACGIH TLV for graphite (all forms) is linked tothat of coal at 2 mg/m³ respirable dust. In Australia the adoptedexposure standard for coal dust is 3 mg/m³ and differs from theACGIH value as a result of different sampling strategies and respirable dustcriteria.

3. RECOMMENDATION FOR EXPOSURE STANDARD

The Exposure Standards Working Group recommends that a time-weightedaverage exposure standard of 3 mg/m³ (respirable) be adopted forgraphite (all forms except fibres) which contains less than 1% crystallinesilica. This exposure standard is based on the established link betweengraphite and coal dust, with due consideration for the exposure standard forcoal dust in Australia, and should be low enough to control pneumoconiosis ingraphite workers.

This standard will be reviewed in the light of any review of the coal dustexposure standard.

REFERENCES

1. ACGIH, Documentation of the Threshold Limit Values and BiologicalExposure Indices, 6th ed, American Conference of Governmental IndustrialHygienists, Cincinnati, Ohio, 1991.