Occupational Knowledge International Silica Exposures in Stone Crushing

OK International • 220 Montgomery Street Suite, 1027 • San Francisco, CA • 94104

Airborne silica generated from stone crushing mills is causing silicosis, cancer, other lung disease, and is a significant contributing factor leading to Tuberculosis (TB). This situation is prevalent throughout India and other developing countries that are rapidly investing in infrastructure and other construction projects. Silica exposures from the Indian stone crushing mills contribute directly and indirectly to poverty in the communities in which they operate. Those who work in the stone crushing mills in India are approximately seven times more likely to have active TB (prevalence of 10.7% compared to 1.6% in the general population). A study of workers previously employed in one cluster outside New Delhi found that 68% had silica-related disease. The majority of workers in stone crusher mills are disadvantaged women and children with little access to medical care. Construction in India is growing rapidly, resulting in the proliferation of stone crushing mills. Though reliable statistics are lacking for this industrial sector, it is estimated that there are more than 12,000 stone crushing units in India providing direct employment to 500,000 people. We estimate that the public health impact of introducing water spray systems in all stone crusher mills in India would prevent 90,000 cases of silicosis and 36,000 deaths from cancer and TB over the next 15 years. Starting in 2003, OK International formed a partnership with the local Indian NGO, Jeevan Rekha Parishad (JRP) based in the South Indian State of Orissa, to provide technical assistance to help reduce silica emissions in local stone crusher mills. We adopted low cost water spray technology to control this deadly dust. With a modest education and outreach effort, over 40 mill owners voluntarily installed water spray systems to reduce silica levels in their operations. The results of this pilot program has been published in the International Journal of Occupational and Environmental Health documenting reductions in average respirable silica exposures of 80% following the installation of water spray controls. (International Journal of Occupational and Environmental Health, 2008; 14:94-103) As mill owners in this area learned more about silica hazards through the training sessions and witnessed their competitors installing this technology, the project actually began to create a “demand” for the water spray systems. The success of this pilot program suggests that relatively inexpensive water spray technology using equipment currently available in the local market can be effective at reducing silica exposures. For additional information see: http://www.okinternational.org/projects.html Please note that OK International in cooperation with the Public Health Foundation of India will be holding a national workshop on this topic in New Delhi on December 12-13, 2009.