CRYSTALLINE SILICA: WHAT AND WHERE IT IS
Oxygen and silicon are the two elements that predominate in the composition of the Earth's crust, the former accounting for 60% and the latter for 20%. When these two elements combine, they give rise to the most common compound in the Earth's crust: Silicon Dioxide or Silica, with the chemical formula SiO2, which is present in many of the stones we know, as well as in glass and ceramics.
Silica can be found in various forms, which can be divided into two macro-families:
1. Amorphous silica
2. Crystalline silica
THE EFFECTS ON HEALTH OF CRYSTALLINE SILICA
Crystalline forms of silica are the most common in nature. Minerals and siliceous stones, as well as finished products made from them, which we walk on and handle every day, pose absolutely no health problems. However, they can be dangerous if they are reduced to a fine powder which, if constantly inhaled over time, can damage the lung tissue and cause serious damage to health.
Fine crystalline silica dust can be generated by dry processing of silica stones, such as grinding and crushing, cutting, calibrating, polishing and suchlike.
The most common disease caused by prolonged inhalation of these silica dusts is silicosis, which in a severe form may cause irreparable damage to the pulmonary system. In more serious situations, lung cancer may also occur.
In 2012, the IARC - International Agency for Research on Cancer - recognised crystalline silica in its respirable fraction as a carcinogen.
INTERNATIONAL AND NATIONAL REGULATIONS
The problem of occupational diseases related to exposure to silica is very much felt at all levels, so that several organisations, both at national and international level, deal with it.
In Italy, since 2003, there has been the NIS - Network Italiano Silice (Italian Silica Network), which deals with the dissemination of technical documents to manage the risk of occupational exposure, also in collaboration with the local health authorities.
In Europe, the main organisation is NEPSI - European Network for Silica, formed by the European sectoral associations of employees and employers who, on 25 April 2006, signed the Social Dialogue "Agreement on Workers' Health Protection through the Correct Handling and Use of Crystalline Silica and Products Containing it".
The Network has published several studies and documents, the most relevant one being the "Guide to Good Practice for Workers' Health Protection", a vademecum that helps to assess the risk of exposure and procedures for its prevention.
CRYSTALLINE SILICA IN THE STONE INDUSTRY
The stone industry processes different types of stone, whose content in quartz/cristobalite can be extremely variable. Commonly processed materials in the stone industry with a significant quartz content include: granite (20-60% quartz), quartzites and sandstones (95% quartz), quartz-based engineered stone (75% quartz), and ceramics (10-15% quartz).
Technological operations (sawing, calibrating, smoothing/polishing, shaping, etc.) are normally carried out in the industries with dedicated machinery using water, which helps to drastically reduce the dispersion of dust in the environment and, therefore, the degree of workers exposure to crystalline silica dust.
It is estimated that, with an adequate water flow, at least 99% of the dust generated by the tools is removed and evacuated with the water used for machining. The remaining part, normally less than 1%, is nebulized into the air through small water droplets (aerosols) generated by rotating tools, which in poorly ventilated environments can then deposit on the surrounding surfaces and subsequently dry out. To avoid the risk that the small percentage of dust deposited on the surfaces after the drying of the aerosol is lifted by air currents, it is necessary to wash the surfaces of the working environment frequently.
In certain working conditions, particularly those outside industrial environments, unfortunately not all machining operations are carried out using water and, as a result, a considerable amount of dust, potentially containing crystalline silica, is dispersed into the environment. If it is not removed with extraction equipment, the dust remains suspended in the air and settles on the surrounding surfaces, only to rise again with any air currents.
As a result, operators are at serious risk of inhaling large quantities of dust if they are not provided with adequate personal safety equipment.
SAFETY AND PREVENTION: THE BRETON PILLARS
Breton has always been committed to perfecting technologies and production processes in the natural stone and composite stone industry, respecting the environment and the health and safety of people.
All Breton equipment and machines work with adequate water flows, complying with the most stringent limits imposed by regulations. Furthermore, machine users are provided with appropriate operating instructions regarding the cleaning of the workplace and the possible use of PPE to avoid exposure to dust potentially containing crystalline silica.
But Breton, aware of the fact that in certain work situations where there is little concern for environmental health there is a risk of dispersed fine dust, has gone even further. It has therefore developed technologies and products with exceptional physical and mechanical properties but silica-free.
It has developed Lapitec®, a sintered stone composed of pure natural minerals with superior aesthetic and physical characteristics that does not contain quartz.
It has also recently developed Bioquarzo®, an industrial quartz free of crystalline silica that can be used as an alternative raw material to natural quartz for the manufacture of Bretonstone® (quartz-based engineered stone).