Health risk effects from prolonged talc exposure not conclusive

5th October 2012

By: Yolandi Booyens


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While studies have confirmed a link between talc exposure and lung disease, a direct link with lung cancer has not yet been confirmed, says occupational health and hygiene provider Boletshe OHH Solutions owner and principal occupational hygienist Mohlabani Jan Mepha.

Some studies suggest a slight increased risk of lung cancer while others have found no increase of lung cancer risk. Therefore, research in this area still continues.

He adds that crushing and milling plants pose a higher risk of talc exposure than mining operations, owing to the crushing, moisture removal, further crushing, screening and transportation of minerals, which exposes workers to dust that contains higher mineral concentrates.

He asserts that adequate research on the health effects of talc exposure has been conducted by institutes like the US National Institute for Occupational Safety and Health (NIOSH), the International Agency for Research on Cancer, which is part of the World Health Organisation, the National Toxicology Programme, an inter- agency programme run by the US Department of Health and Human Services and the American Cancer Society.

The NIOSH conducted studies on the health effects of mining and milling talc. The mortality and medical study included 710 men who previously mined and milled talc for at least one day between 1947 and 1978, Mepha states. The purpose of the study was to see if exposure to talc on mines and at mills is associated with lung disease and lung cancer.

The mortality study compared the death rates in talc workers with the death rates in the general US population and found that talc workers were more likely to have noncancer lung diseases (eight deaths found, about three expected) owing to inhaling dust produced while mining and milling talc, as well as by smoking.
In addition, the Medical Study of the Lung, conducted in 1975, examined the lungs of 121 employees who were then employed in the talc mining and milling industry. The study included breathing tests, chest X-rays and medical questionnaires.

The study found that the lungs of some talc workers had been affected by noncancer lung diseases possibly owing to breathing dust produced while mining and milling talc, as well as by smoking.

There is a possibility that workers who mine and mill talc are likely to contract lung cancer from exposure to talc containing high concentrations of crystalline silica asbestos, Mepha notes.

He states that a link between lung diseases, such as pneumoconiosis, obstructive airway disease and cardiopulmonary tuberculosis, and talc exposure, was confirmed.

However, a National Toxicology Programme study, titled ‘Toxicology and carcinogenesis studies of talc (GAS No 14807-96-6) in F344/N rats and B6C3F mice (inhalation studies), Technical Report Series No 421’, published in 1993, reported that epidemiology studies suggested an association between non- fibrous talc and lung-cancer risk.

Health and Safety Protection in South Africa

Mepha states that there is adequate legislation in place to protect the health and safety of workers in the min- ing and mineral processing industries in South Africa.

The Mine Health and Safety Amendment Act and its regulations promulgated under the Minerals Act are enforced by the Department of Mineral Resources at all applicable operations to ensure the health and safety of mine- workers.

“To realise reduced exposure to mineral dust in the mining industry, elimination control needs to be implemented and, where it is not reasonably practical to implement elimination control, engineering controls and administrative control measures should be implemented,” Mepha states.

Mineral dust exposure can be reduced by using dust collection or wet dust suppression systems. The former uses local exhaust ventilation principles to capture airborne dust from the source and transport it through ducting to a dust collector. The latter uses water or water sprays with surfactant or foam to wet the mined material so that it has a reduced tendency to generate dust.

Further, airborne dust capture can be implemented by spraying fine water droplets onto airborne dust clouds. This causes dust particles to collide and form agglomerates, which, when they become too heavy to remain airborne, separate from the air stream, Mepha notes.

“Dust exposure can also be reduced by isolating workers and placing them in an operator booth, control room or enclosed cab supplied with fresh, clean, filtered air.”

Mepha emphasises that administrative controls, such as training and awareness, operating procedures, work practices and employee exposure monitoring programmes, should be implemented by mining operations to ensure that mineral dust exposure is limited.

“When engineering controls are not feasible and safe work practices do not provide sufficient protection, personal protective equipment, such as dust masks, should be introduced,” Mepha stresses.

Edited by Tracy Hancock
Creamer Media Contributing Editor


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