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Preventing tuberculosis among silica dust exposed workers
  1. International Commission on Occupational Health (ICOH)
  1. Occupational Knowledge International, San Francisco, CA 94118, USA
  1. Correspondence to , Perry Gottesfeld MPH Occupational Knowledge International, San Francisco, CA 94118, USA; pgottesfeld{at}okinternational.org

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The International Commission on Occupational Health (ICOH) calls for a concerted global effort to promote occupational safety and health strategies to prevent tuberculosis (TB) in high-risk occupations, including silica dust exposed workers in mining, construction and other industries. The highest exposed are often the most vulnerable, disadvantaged and medically underserved in countries with the highest burden of TB. We encourage governments, businesses and global health funders to invest in control measures to prevent TB among silica exposed workers consistent with the Moscow Declaration to End TB.

Silica exposed workers

Exposure to silica dust is a potent risk factor for TB, as demonstrated in multiple studies, notably among exposed miners and stone crushers.1–3 Silicosis, a lung disease caused by exposure to crystalline silica dust, is one of the most common occupational lung diseases worldwide.4 In addition, silicosis increases the risk of active TB by up to fourfold, and HIV increases the risk approximately fivefold.2 The combination of silicosis and HIV produces a multiplicative effect, increasing the risk of acquiring active TB by 15 times greater than in individuals without silicosis and HIV.2 Furthermore, exposure to silica dust in the absence of clinically evident silicosis also has been demonstrated to increase the life-long risk for TB.5

Silicosis is entirely preventable by reducing or eliminating exposures to silica dust in the workplace with improved ventilation and the use of wet methods. In small stone crusher mills in India with limited resources, water spray controls reduced respirable silica by 80%.6 Reducing exposures to silica decreases the likelihood of developing silicosis, lung cancer and TB. The feasibility and efficacy of dust controls in reducing TB prevalence and mortality among exposed workers have been clearly demonstrated in multiple studies, including those from South Africa, Italy and the USA.7–9

Preventing silicosis by investing in engineering controls to reduce silica dust emissions is one of the most cost-effective public health interventions in the workplace.10 Accounting for TB, lung cancer and other silica-related diseases in the analysis would further increase the cost-effectiveness.10 Investments in dust controls in the workplace to prevent disease are more cost-effective than investing in public health programmes to identify and treat cases of TB.11 12

The labour force at greatest risk includes the 227 million mostly informal, often migrant, workers in construction and mining.13 14 This estimate includes 40.5 million artisanal small-scale miners operating in more than 80 countries around the world.13 At least one million children are employed in artisanal mining.15 As many of these workers migrate to job sites, the impacts of TB are often amplified in home communities.

In light of the overwhelming evidence linking the prevalence of silicosis and TB to silica exposure in occupational settings, ICOH is calling for global action to reduce silica exposures in high-risk populations. Given the significant potential to prevent TB with silica dust controls in countries around the world, ICOH encourages governments, multilateral institutions, global health funders and businesses to invest and engage in the following:

Silica dust controls

  • Governments and businesses should adopt action plans to reduce silica dust exposures in high-risk occupations, including mining, quarries, construction, ceramics, foundries and silica flour mills.

  • Expand the scope of existing TB education and treatment programmes to incorporate silica dust control measures in both large-scale industries and small-scale mining and stone crushing communities in high burden countries.

  • UN agencies and governments should promote dust controls to reduce silica exposures in small-scale gold mining operations as part of future projects focused on reducing mercury hazards under the Minamata Convention.

  • Lending institutions and governments should increase loans, grants and tax incentives to encourage the installation of engineering controls to reduce silica exposures in mining and other industries significantly affected by these comorbidities of TB and silicosis.

  • Governments and lending institutions should develop guidelines and specifications for large infrastructure projects to include specific requirements to control silica dust exposures.

  • Employers and workers organisations should provide training programmes illustrating safer work practices to reduce dust exposures.

Regulatory approaches

  • Governments should develop, adopt, disseminate and enforce regulations for controlling silica exposures in the workplace and invest in building capacity within relevant regulatory agencies.

  • Governments should expand worker compensation programmes to cover silicosis, TB and silicotuberculosis in both the formal and informal sectors. Costs for these programmes to be passed on to employers to incentivise improvements in working conditions.

Building capacity to respond

  • Increase research on the link between silica and TB and the efficacy of dust-reduction efforts.

  • Teaching and training institutions should expand training programmes for health professionals to better recognise and diagnose silicosis and silicotuberculosis.

  • The WHO and International Labour Organization should revitalise and expand the Global Programme for the Elimination of Silicosis initiative and increase assistance to governments to adopt new regulations and establish silica reduction programmes.16

Acknowledgments

This call for action was written by Perry Gottesfeld with input to the draft provided by Marilyn Fingerhut, David Rees, Rodney Ehrlich, Paula Akugizibwe and Jill Murray. The statement was approved by the International Commission on Occupational Health (ICOH) in April 2018.

References

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Footnotes

  • Competing interests None declared.

  • Patient consent Not required.

  • Provenance and peer review Not commissioned; internally peer reviewed.

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