Danger Dust

Silica is the most plentiful mineral on earth and is the primary constituent in most rocks.

The respirable form of silica is small enough to reach the terminal bronchioles and alveoli of the respiratory system.

Typical immune mechanisms cannot clear these particles from the lung, initiating a pathologic cycle of inflammation and parenchymal damage that ultimately leads to silicosis.

Silicosis is the world's most prevalent occupational lung disease and is characterized by irreversible, progressive pulmonary fibrosis leading to restrictive lung disease. Silicosis is a preventable disease with significant morbidity and mortality that has no cure.

Education on prevention, screening, timely diagnosis, avoidance of exacerbating factors, and treatment of complications is imperative. 

Silicosis, a type of pneumoconiosis, occurs secondary to the inhalation of RCS and causes progressive, irreversible, and fatal lung inflammation and fibrosis.While the condition is preventable, no treatment exists.

Silicosis increases susceptibility to Mycobacterial diseases, autoimmune diseases, and bronchogenic carcinoma.

It is generally agreed that the majority of the deaths and destruction were caused by an explosion of coal dust which swept through the mine. However it has never been ascertained what caused the initial ignition of the coal dust.

Two main causes have been hypothesized:

An accident during the handling of mining explosives.

Ignition of methane by the naked flame of a miner's lamp.

A group of 13 survivors, known later as the rescapés, was found by rescuers on 30 March, 20 days after the explosion.

They had survived at first by eating bark from the crossbeams, later by eating a rotting mine horse. They avoided dehydration by drinking the water dripping from the walls.

The two eldest (39 and 40 years old) were awarded the Légion d'honneur, the other eleven (including three younger than 18 years of age) received the Médaille d'or du courage.

A final survivor was found on 4 April.

At that time, young boys were sent naked up the narrow chimneys, and Pott was inclined to blame the origin of the malignancy on the lodging of soot in the rugae of the scrotum.

In 1982, the first findings from our initial epidemiological cohort study of 2071 Swedish chimney sweeps were published, showing increased mortality from several types of cancer, ischemic heart disease, diseases of the respiratory system, and accidents, injuries, or other external causes.

Follow-up studies (in 1987 and 1993) of an expanded cohort confirmed the initial findings on mortality.

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A middle-aged male working in the sandblasting and stone-cutting industry was brought to the medicine department with skin tightness, dysphagia and discolouration of the skin for the last 1 year.

On examination, he had skin thickening over the face and the extremities with restricted mouth opening. His hands were cold and showed peripheral cyanosis. Systemic examination was suggestive of diffuse cutaneous systemic sclerosis, further confirmed by the antinuclear antibody testing.

Further, CT of the chest showed mediastinal lymphadenopathy with eggshell calcification and interstitial fibrosis consistent with silicosis and fibrotic non-specific interstitial pneumonitis. 

Taken together, diverse disease-relevant autoreactive B cells, including cells specific for DNA, MPO, and basement membrane, are recruited to lung ectopic lymphoid aggregates in response to cSiO2 instillation. B cells that escape tolerance can contribute to local autoantibody production. Our demonstration of significantly enhanced autoantibody induction by TLR ligands further suggests that a coordinated environmental co-exposure can magnify autoimmune vulnerability.

Silicosis is a work-related disease that is entirely preventable. It is on the rise globally due in part to weak regulators and companies putting profit before the safety of workers.

"Continued work with engineered stone poses an unacceptable risk to workers,” the report said.

“The use of all engineered stone should be prohibited.”

“There is no scientific evidence for a ‘safe’ threshold of crystalline silica content in engineered stone,”

The individuals exhibiting three bands in LFA (CC16 concentration > 9 ng/ml) need not go for X-ray. This can significantly decrease the risk of X-ray exposure to the individuals. Hence, this assay would be useful for early detection of silicosis for various purposes such as notification to the local authority, secondary prevention and financial compensation as per guidelines of the country.

Key learning points

What is already known about this subject:

Traditional silica exposure industries such as quarries continue to contribute to silicosis despite artificial stone related silicosis renewing attention.

What this study adds:

Any worker in at-risk industries with respirable crystalline silica exposure should have silicosis as a potential differential diagnosis, regardless of gender or role description.

A safe silica dust exposure level is not known and is likely not to exist.

What impact may this have on practice or policy:

Implementation and adherence to preventative measures need to occur throughout workplaces handling silica-containing stone, not just at the stone-cutting interface.

Early in 1951, Saita G et al.firstly reported that the renal functions were decreased in some silicosis patients. Subsequently, several epidemiological evidences suggested that the silica exposure was associated with an increased risk of end-stage renal disease (ESRD), chronic kidney disease (CKD), or specifically glomerulonephritis.

Silica nephropathy referred to the floorboard of kidney diseases after exposure to silica or silicon dioxide, including tubulo-interstitial disease, immune-mediated disease, chronic kidney disease, and end-stage renal disease. In literatures, the renal histopathology of silica nephropathy was varied, including focal glomerureview

ritis, necrotizing glomerulonephritis, crescentic glomerulonephritis, etc. 

The study demonstrates that dry processing of artificial stone has been extremely common.

Also, the sensitivity and positive predictive values of respiratory function tests and chest X-ray as screening tests to detect silicosis in this high-risk occupational group are inadequate.

Female sex and a later stage of pneumoconiosis were independent risk factors for pneumoconiosis with CTD.

These findings provide a new evidence for the high prevention of autoimmune diseases in pneumoconiosis, calling for the formulation of early detection and strengthening prevention strategies

Moreover, the tunability of silica offers a plethora of further opportunities to bind to other analytes with improved selectivity, by changing the particle size, pore size and functional groups. While this paper has focused on common face coverings, the utilisation of silica as a virion adsorbent shows excellent potential for use in face coverings, air filtration systems and even as a bioaerosol sampler.

The primary causes of silicosis are inhaling crystalline silica in high concentrations over a short duration or in lower concentrations over a long period. The particles must be airborne and small enough for a person to breathe them into the lungs. Exposure to silica dust in the workplace is the most significant contributing factor. 

Inhaled particles make their way into the lungs and become lodged in the tissues, which causes chronic inflammation and an overactive immune response. The damage leads to the formation of the fibrous nodules that characterize the disease. 

NOT TODAY. BUT YEARS DOWN THE LINE.

DON’T RISK YOUR OR YOUR WORKERS LONG-TERM HEALTH. PROTECT LUNGS FROM DUST.

Construction workers die every week from lung diseases caused by exposure to dust. Many more suffer from severe chronic long-term lung conditions. 

Don’t make the same mistake as those who have not realised the health risks of exposure to dust and have worked unprotected. 

Make sure you are aware of the risks and know what to do to keep you and your workers safe. Learn more about HSE’s construction site inspection initiative with a focus on respiratory health: HSE targets construction workers’ lung health with nationwide inspection campaign 

Of growing interest has been the role of silica in multisystem disease, notably rheumatoid arthritis, systemic sclerosis, systemic lupus erythematosus (SLE), small vessel vasculitis and others, in which autoimmunity is the unifying feature. 

For SLE and small vessel vasculitis in men, there was arguably no dose-response trend beyond the ‘any silica’ threshold.

The multisystem nature of the silica hazard also has implications for medical practice. Specialists in fields other than respiratory medicine—renal medicine, dermatology and rheumatology—need to be on the alert, not least by taking a careful occupational history with knowledge of silica exposures.

Finally, autoimmunity widens the mechanistic complexity of silica toxicology. Variability in dose rate of silica, particle parameters such as size, charge and physicochemical structure, co-exposures and host factors require painstaking studies controlling for these variables to determine their joint effects. Such research has the potential not only to identify pathways to earlier identification and possible treatment of silicosis, but also to illuminate aspects of autoimmunity, tuberculogenesis and other disease processes.