Silicosis is the oldest, most severe and most prevalent lung disease related to inhalation of mineral dust, confirming its importance in the list of pneumoconioses. The description of the disease has been reported for many centuries.

It is a chronic and incurable pulmonary disease, with a progressive and irreversible evolution that can determine work incapacity, disability, increased susceptibility to tuberculosis and often related to the cause of death of the affected patient. It is a nodular pulmonary fibrosis caused by inhalation of dust containing fine particles of crystalline free silica that takes months to decades to manifest.

The WHO International Cancer Research Agency (IARC) considers inhaled crystalline free silica to be a Group 1 carcinogen (in experimental and human situations).

Although much is known about this perfectly preventable occupational disease, still in the 21st century silicosis continues to kill workers around the world. Thousands of new cases are diagnosed each year in various parts of the world with predominance in developing countries where activities involving exposure to silica are very frequent, highlighting that in developed countries pneumoconioses are in rapid decline.

In Brazil, the identification of new cases is epidemic and silicosis is considered the main occupational pulmonary disease due to the high number of workers exposed to silica and unfortunately there is no exact statistics on the cases of patients. It is responsible for the disability and death of numerous workers in various activities.

The disease that can be prevented is important on the agenda of international health and work organizations, such as the International Labor Organization (ILO) and the World Health Organization (WHO), which in 1995 launched a joint program for the global elimination of silicosis. the ambitious intention to drastically decrease its worldwide prevalence. This program aims essentially to apply the knowledge accumulated in the last decades in primary disease prevention actions and seeks to promote the collaboration of member countries to establish measures and programs that lead to the elimination of this disease by 2030.

From November 6 to 10, 2000, FUNDACENTRO, the Evangelical Faculty of Medicine of Paraná and the Oswaldo Cruz Foundation, supported by the ILO and WHO, and numerous governmental and non-governmental institutions held the International Seminar on Exposure to Silica. – Prevention and Control. The Seminar was an initiative that met the objectives proposed by the international program for the global elimination of silicosis, as it debated issues pertaining to the disease situation in Brazil, focusing on prevention and control measures, seeking to identify and disseminate the forms and means that these actions and measures can be effectively applied. ( Annex 1)

1., Reference document.
2. Occupational Hygienist, CIH *, Consultant, 26 ch.Colladon, 1209 Geneve, Switzerland.
* Certified by the American Board of Industrial Hygiene.
3.Physician, Occupational Health Director of the Curitiba PM, Prof. from the Evangelical Faculty of Paraná.

Occupational Risks 

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The risk of acquiring silicosis basically depends on three factors: breathable dust concentration, percentage of free and crystalline silica in the dust and duration of exposure.

Breathable dust is often invisible to the naked eye and is so light that it can remain in the air for a long period of time. These dusts can also travel long distances, suspended in the air, and affect workers who are apparently not at risk.

Silica dust is released when performing operations such as cutting, sawing, polishing, grinding, crushing, or any other subdivision of materials containing free crystalline silica such as sand, concrete, certain ores and rocks, blasting. sand and transfer or handling of certain materials in powder form.

In Brazil, the activities that present the highest risk of acquiring silicosis are:

• Extractive industry (underground and open pit mining, rock drilling and other extraction activities such as quarries and ore processing and mineral-containing rocks);

• Casting of iron, steel or other metals using sand molds;

• Ceramics where floors, tiles, sanitary wares, household wares and others are made;

• Production and use of refractory bricks (construction and maintenance of blast furnaces);

• Glass making (both in the preparation as well as in the use of sandblasting used for opacification or decorative work);

• Rock drilling in the construction of tunnels, dams and roads;

• Grinding quartz and other stones containing free and crystalline silica;

• Sand blasting (used in the naval industry, glass opacification, casting, polishing of parts in the metallurgical industry and polishing of ornamental parts);

• Execution of marblework4 with granite, slate and other decorative stones.

• Manufacture of abrasive material.

• Excavation of wells.

• It is important to highlight Civil Construction, where workers may be exposed to large amounts of fine silica dust in operations such as carving, using hammers, drilling, cutting, grinding, sawing, moving materials and cargo, mason work, demolition, abrasive blasting. concrete (even if sand is not used as an abrasive), dry sweeping, concrete cleaning or compressed air masonry.

Another operation that deserves attention is sand blasting that offers a high risk of silicosis and has been presenting the most severe cases of the disease in Brazil. It is important to note that any abrasive blast, even if the abrasive material does not contain silica, can present the risk of silicosis if used to remove silica-containing materials such as sand mold remnants on metal profiles.

In addition, exposure to silica dust can occur in unexpected situations such as workers handling and repairing tires, where compressed air is widely used to clean tires and the shop floor. There have been cases in prosthesis preparation work using sand “jet” to work the material.

4. In Brazil the term marble is used for places where we work with various types of minerals and especially granite that is a major responsible for cases of silicosis in this area.

Epidemiology 

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Disease onset with temporary or permanent disability and / or death has been constant in developed countries, and even more so in developing countries where there is often excessive exposure to respirable dust containing free and crystalline silica.

In Vietnam, silicosis is considered to be one of the most prevalent occupational diseases and the disease is one of the major causes of providing workers with social security benefits (90%). Recent data show that the number of accumulated cases so far is approximately 9,000 cases.

In China, in 1990, there were approximately 360,000 accumulated cases of pneumoconiosis. During the period 1991-1995, China documented more than 500,000 cases of silicosis, with almost 6,000 new cases occurring each year and more than 24,000 deaths per year, mostly among older workers.

In India, a 55% prevalence of silicosis was found among workers, many of them young, working in shale sedimentary rock quarries, and with subsequent activity in small, poorly ventilated sites.

Studies in Malaysia show a prevalence of silicosis of 25% in quarry workers and 36% in workers making burial tombstones.

In the US, it is estimated that over 1 million workers are occupationally exposed to free and crystalline silica dust, and 100,000 of these workers are at risk for silicosis. Each year, more than 250 workers die from silicosis.

In Brazil, silicosis is also one of the most prevalent pneumoconioses and the estimated number of workers potentially exposed to silica dust is over 6 million, with 4 million in construction, 500,000 in mining and mining and over 2 million in mining industries. mineral processing, metallurgy, chemical industry, rubber, ceramics and glass.

There is a marked tendency for the emergence of new cases, the significance of which should be credited more to the increase in diagnoses resulting from active case search than to the increase in the problem. Estimates of the prevalence of silicosis in Brazil suggest that there are 25 to 30,000 cases of this pneumoconiosis in the country. (Mendes, 1978)

Studies show the following prevalence chart:

• Open quarries – 3.0%

• Ceramics – 3.9%

• Foundries – 4.5%

• Marine Industry (sand blasting) – 23.6%

• Well digging (Ceará, 1986-1989) – 27%

• In Minas Gerais, over 4,500 workers were diagnosed with silicosis, and it is estimated that there are around 7,500 cases.

• In Paraná, the Metropolitan Center for Workers’ Health Support – CEMAST / SESA, since 1996, registered among the confirmed cases, suspects and deaths, 142 occurrences in workers of Curitiba and Metropolitan Region. In the last 3 years there have been 59 cases of silicosis with 10 deaths. Mining has the highest number of confirmed cases with 37 occurrences, 2 of which died. Sand blasting showed 17 confirmed and 16 suspected cases under investigation. Eight workers died. In the foundry, body shop and ceramics were recorded 43 cases, 5 confirmed and 38 under investigation.

3. The data included in the text refer to those presented by various experts during the International Seminar on Exposure to Silica held in Curitiba.

Prevention 

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In order to prevent silicosis exposure and inhalation of respirable dust containing free crystalline silica should be avoided by appropriate primary prevention technologies aimed at:

• Avoid the use of materials containing free and crystalline silica;

• Prevent or reduce dust formation;

• Prevent or control the spread of dust in the workplace;

• Prevent workers from inhaling dust.

Primary prevention should follow the following control hierarchy:

• At the source of the hazard (which should be the first choice) by measures such as:
  * Replacement of sand as an abrasive with less hazardous materials;
  * Use of materials in a less dusty form;
  * Process modification to produce less dust;
  * Use of wet methods.

• In risk transmission (between source and receiver):
  Once dust is generated, its spread in the workplace should be prevented or controlled by measures such as:
  * Isolation, enclosure of operations;
  * Local exhaust ventilation;
  * Cleaning in the workplace.

• At work:
  * Use of good quality, efficient respiratory protection that fits the worker’s face and well used within a program that includes maintenance, cleaning and filter replacement.

Another very important preventive strategy is to promote the dissemination of information to workers and employers about the risks of exposure to silica and workplace prevention and control measures as well as personal hygiene measures.

Epidemiological surveillance is also important as it can detect cases early and is an indispensable complement to primary prevention.

Difficulties  

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As we can see Silicosis is a perfectly preventable disease. There is technology and methods available to prevent it and there is worldwide interest in seeking its elimination.

However, in many parts of the world, we face numerous difficulties in successfully controlling the disease:

• Lack of primary prevention in the workplace;

• Failures in the legislation of some countries;

• Insufficient or inadequate human and financial resources;

• Lack of proper qualification of professionals working in the area;

• Difficulties in reaching small businesses and the informal sector;

• Inadequate preventive approaches with “preventive” programs based primarily on surveillance and medical services with a greater emphasis on early case detection than prevention of their occurrence;

• Preventive action block because quantitative assessment is not possible;

• Failures in the prevention and control of occupational hazards: lack of early preventive action and lack of multidisciplinary work;

• Lack of well-planned, well-managed and sustainable prevention and control programs.

From experiences in other countries, an important factor in helping preventive action is the political will to solve the problem. One aspect that negatively influences political will is the deficiency in statistics on silicosis and other occupational diseases in general, resulting from difficulties in diagnosing the disease and reporting problems, particularly in small businesses, mining and the construction industry where many workers are not. are properly recorded, leading to a fragmentary and partial view of the problem.

Measures Required to Eliminate Silicosis 

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In order to achieve the goal of eliminating silicosis, the following steps are essential:

• awareness of the problem of silicosis and its magnitude, as well as political will, motivation and commitment (at all levels) to address it;

• design and implementation of a national policy, accompanied by an action plan that includes efficient prevention and control programs in hazardous workplaces, to avoid exposure to the etiological agent (ie dust containing free and crystalline silica), as well as environmental and epidemiological surveillance.

This requires several actions:

A. Promote awareness and political will for the establishment and implementation of appropriate policies and programs.

Knowledge about silicosis and its prevention exists, but is not sufficiently disseminated. Many people who could play an important role in their prevention, including workers, do not have all the necessary knowledge.

It is important to promote the dissemination of information with efficient tools that reach as many people as possible. As a starting point it is necessary to recognize and accept that there is a problem, to understand the nature of the hazard and the importance of preventing exposure to free crystalline silica dust.

B. Address deficiencies in silicosis statistics

According to PAHO’s estimate: “… in Latin America, reported cases of occupational diseases account for only 1-5% of the cases that actually occur” (PAHO / WHO, 1998). In the case of silicosis, there is a lot of underreporting and therefore the diagnosis and reporting of the disease should be improved in order to obtain and disseminate more accurate statistics, which are essential for achieving the expected results in disease prevention. Promoting studies and research on the magnitude of the problem and developing a vocational training program should also be a priority.

C. Preventing and controlling workplace dust exposure

Effective preventive solutions already exist to eliminate or reduce dust exposure, and there is also scientific and technological knowledge to design new solutions, as well as models for programs and their management. However, the application of theoretical knowledge to practical and realistic solutions should be improved, and successful practices and the resulting benefits should be more widely disseminated.

It is also necessary:

• devote more resources to primary prevention of occupational exposure;

• promote applied research to find efficient and pragmatic solutions;

• follow appropriate preventive approaches;

• develop mechanisms to reach small businesses, the construction industry and the informal sector;

Preventive measures should be integrated into effective prevention and control programs that are well planned, managed and sustainable. They should also be multidisciplinary and include risk communication and education, as well as environmental and epidemiological surveillance.

D. Human Resource Development

Human resource development is essential both for assessing the magnitude of the problem (including proper diagnosis and environmental assessments) and for preventing it, which requires technical knowledge of control principles, implementation of effective control strategies and programs.

As for human resources, in general, it is necessary to:

• identify existing needs and resources;

• plan courses for decision makers (government, employers and workers) as well as risk communication (for workers);

• promote specialized training of occupational health professionals (including “training trainers”);

• prepare educational materials for different levels.

In order to foster a multidisciplinary working spirit, it is advisable to take some common courses for different occupational health professionals.

Final comments 

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In conclusion, for successful silicosis elimination, it is necessary to:

• Establish a National Policy;

• Political will with motivation and commitment at all levels: governmental (national and local) and in companies, with commitment of workers and employers;

• Develop a plan with an intersectoral approach that enables a partnership with all agencies and institutions, governmental or otherwise, that are related to the problem;

• Seek to partner with bodies and other scientific organizations from around the world;

• Continuously promote the dissemination of information to workers and employers on the risks of silica exposure and disease prevention measures;

• Promote the development of human resources capable of addressing and solving the problem;

• Develop efficient and multidisciplinary preventive programs, with political support, sound technical base and good management;

• Continuously evaluate preventive programs, including environmental surveillance and health surveillance on exposed workers;

• Develop appropriate research that offers technically and financially viable solutions;

• Promote an intensive outreach campaign on the existence of the problem, appropriate preventive measures, as well as providing access to information at all levels.

International cooperation 

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International agencies can contribute to the development of national programs as they provide an overview of the problems, can promote and facilitate exchanges of knowledge and experience (thus helping to avoid duplication of effort and waste of resources), can guide and facilitate resource development. human resources and adequate infrastructure. But the problem can only be solved at country level.

International Action to Eliminate Silicosis The magnitude of the worldwide problem has made the issue prominent on the joint ILO-WHO agenda culminating in 1995 with the launch of the “ILO / WHO International Program for Global Elimination of Silicosis”

The objective of the Joint Program is to promote the development of National Silicosis Elimination Programs that can significantly reduce disease incidence rates by the year 2010, and eliminate silicosis as a public health problem by the year 2030.

The principles of action of the ILO / WHO Joint Program are:

• Formulation of regional, national and global action plans;

• Mobilization of resources for application of primary and secondary prevention;

• Epidemiological surveillance;

• Monitoring and evaluation of results;

• Strengthening of the national resources and competences necessary for the establishment of national programs;

This international program will depend to a large extent on cooperation between industrialized and developing countries, international organizations and NGOs. At the national level it is important to promote cooperation between government agencies, employers ‘and workers’ organizations, occupational safety and health professionals. , in order to build a solid infrastructure in countries, to prevent and control exposure to silica dust, and thus preventing silicosis.

The Joint Program also aims to promote political will and commitment, intersectoral collaboration, capacity building and information dissemination programs in this field, worker education and risk communication and the harmonization of diagnostic criteria using the ILO International Radiographic Classification, improve early detection of silicosis and facilitate epidemiological comparisons.

NATIONAL PROGRAM 

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The ILO / WHO Joint Program advises that national programs be developed by integrating the above items, and including other actions such as:

• Promote the analysis of the socioeconomic context;

• Identify the groups of workers most exposed;

• Define preventive strategies;

• Seek the involvement of all partners in the implementation of the program;

• Promote tripartite consultation and cooperation;

• Seek institutional support for implementation;

• Establish criteria for program monitoring and evaluation;

• Identify national standards and link to international standards;

• Establish close relationship with environmental protection.

The National Program shall be accompanied by a National Action Plan containing the actions necessary to achieve the goals set in the Program in terms of interinstitutional cooperation and financial and human resources.

The Silicosis Elimination Plan, due to its diagnostic training component, may help to assess the magnitude of all other pneumoconioses, but may also, due to its primary prevention component, help to eliminate other occupational diseases resulting from exposure to dust.

It will certainly contribute to raising awareness, training and educating about systematic and managerial approaches to broader occupational risk prevention programs and to promoting multidisciplinary and intersectoral approaches.

The starting point for the definition of the Brazilian Plan for the Elimination of Silicosis should be the report of the International Seminar on Exposure to Silica held in Curitiba in November 2000. ( Annex 1 )

The National Program, intersectoral and multidisciplinary, should be designed with broad collaboration and coordination at the national level that will seek the participation of all actors directly involved with the issue.

Click on the links to see the full attachment.

Annex 1

International Seminar on Exposure to Silica
“Prevention and Control”
Curitiba – 6th to 10th November 2000

Annex 2

Report of the meeting presenting the results of the International Seminar on Exposure to Silica, held in Brasilia, December 12, 2000, at the headquarters of the International Labor Organization.

Annex 3

Report on the activities of the Workshop on the National Program for the Elimination of Silicosis, held in Brasilia, December 12 and 13, 2001.

Annex 4

Meeting of Governmental Entities, Brasilia, 03/26/2002.