Health hazard assessment

Respirable crystalline silica dust can penetrate deep into the lungs. The body’s natural defence mechanisms may eliminate much of the respirable dust inhaled. However, in case of prolonged exposure to excessive levels of this dust, it becomes difficult to clear the dust from the lungs and an accumulation can, in the long term, lead to irreversible health effects.

For many years, it has been known that prolonged inhalation of respirable crystalline silica may cause a specific type of lung damage called silicosis. In fact, silicosis is the world’s oldest known occupational disease.

A recent hazard assessment of Respirable Crystalline Silica health effects has been commissioned to a team of scientific experts who produced two reports:

  • Review and Hazard Assessment of the Health Effects of Respirable Crystalline Silica (RCS) Exposure to inform Classification and Labelling under the Global Harmonised System: Overview Report (Borm P, Brown T, Donaldson K, Rushton L, 2009); and
  • Review of the Literature of the Health Effects of Occupational Exposure to Crystalline Silica: Silicosis, Cancer and Autoimmune Diseases (Brown T, Rushton L, 2009)

A summary of these reports by Dr Peter Morfeld (Institute for Occupational Medicine of Cologne University, Institute for Occupational Epidemiology and Risk Assessment of Evonik Industries, Essen, Germany) is available here.

He concludes that:

  • Silicosis is the main health effect of RCS exposure.
  • Any potential cancer risk due to RCS exposure is limited to lung cancer.
  • Any lung cancer excess risk is demonstrated only under high occupational exposures to RCS and is heterogeneous across industries.
  • Any cancer effect is indirect/secondary to lung inflammation