Crystalline Silica

How can Logic Health Help with Health Monitoring for Crystalline Silica?

· All Logic Health clinics across the nation can complete the Crystalline Silica Health Monitoring Medical Assessment and Spirometry required for health monitoring

· We will also arrange ILO Chest X-rays or for WA low dose HRCT scans based on the required frequencies (baseline then usually every 3-5 years)

· Logic Health will provide the report on recommendations for a worker whether that be they are suitable to work with silica or if they should be removed until further testing has been conducted.

· Logic Health can manage your annual assessment including the ability to recall employees to complete health monitoring when required ensuring compliance.

What is crystalline silica?

Crystalline silica (silica) is found in sand, stone, concrete and mortar. It is also used to make a variety of products including composite stone used to fabricate kitchen and bathroom benchtops, bricks, tiles and some plastics. When workers cut, crush, drill, polish, saw or grind products that contain silica, dust particles are generated that are small enough to lodge deep in the lungs and cause illness or disease including silicosis.

Silica is silicon dioxide, a naturally occurring and widely abundant mineral that forms the major component of most rocks and soils. There are non-crystalline and crystalline forms of silicon dioxide. The most common type of crystalline silica is quartz (CAS 14808-60-7).

Different types of rock and rock products can contain different amounts of silica, for example:

Type	Amount of silica (%)
Marble	2
Limestone	2
Slate	25 to 40
Shale	22
Granite	20 to 45 (typically 30)
Natural sandstone	70 to 95
Engineered stone	Up to 97
Aggregates, mortar and concrete	| various

What is silica dust?

Silica dust is generated in workplace mechanical processes such as crushing, cutting, drilling, grinding, sawing or polishing of natural stone or man-made products that contain silica. Some dust particles can be so small that they are not visible; these are commonly referred to as respirable particles.

Respirable silica dust particles are small enough to penetrate deep into the lungs and can cause irreversible lung damage.

The non-crystalline or amorphous forms of silica do not cause this kind of lung damage.

Work activities that may represent a high risk exposure

Silica is one of the most abundant minerals found in the earth’s crust and is used in many products across a variety of industries and workplaces. Crystalline silica is most dangerous to health when dust is generated, becomes airborne and is then inhaled by a worker.

Examples of work activities that can generate respirable silica dust particles include:

· during fabrication and installation of composite (engineered or manufactured) stone countertops

· excavation, earth moving and drilling plant operations

· clay and stone processing machine operations

· paving and surfacing

· mining, quarrying and mineral ore treating processes

· tunnelling

· construction labouring activities

· brick, concrete or stone cutting; especially using dry methods · abrasive blasting (blasting agent must not contain greater than 1 per cent of crystalline silica)

· foundry casting

· angle grinding, jack hammering and chiselling of concrete or masonry

· hydraulic fracturing of gas and oil wells, and

· pottery making.

What diseases can silica dust cause?

If a worker is exposed to and breathes in silica dust they could develop:

· acute silicosis

· can develop after a short exposure to very high levels of silica dust, within a few weeks or years, and causes severe inflammation and an outpouring of protein into the lung

· accelerated silicosis

· can develop after exposures of 3 to 10 years to moderate to high levels of silica dust and causes inflammation, protein in the lung and scarring of the lung (fibrotic nodules)

· chronic silicosis

· can develop after long term exposure to lower levels of silica dust and causes fibrotic nodules and shortness of breath

· can include progressive massive fibrosis where the fibrotic nodules in the lung aggregate

· chronic bronchitis

· emphysema

· lung cancer

· kidney damage, or

· scleroderma, a disease of the connective tissue of the body resulting in the formation of scar tissue in the skin, joints and other organs of the body.

Choosing the best control measure

Under the model WHS Regulations, A person conducting a business or undertaking (PCBUs) have specific duties to manage the risks to health and safety when using, handling, generating and storing hazardous chemicals, including silica. PCBUs also have a duty to ensure the workplace exposure standard for crystalline silica is not exceeded and to provide health monitoring to workers. Managing risks and worker exposures to silica can be achieved by selecting and implementing measures using the hierarchy of controls:

· substitution such as sourcing composite stone benchtops with a lower percentage of silica

· isolation of the hazard – using principles of safe work design to designate areas for tasks that generate dust and appropriate worker positioning during these tasks, using enclosures and automation to conduct dust generating tasks.

· engineering controls that minimise the risk of exposure to generated dust, for example, local exhaust ventilation, water suppression (wet cutting) or using tools with dust collection attachments

· should a risk still remain; administrative controls, including good housekeeping policies, shift rotations and modifying cutting sequences.

· should a risk still remain; personal protective equipment including appropriate respiratory equipment (generally a minimum of a P2 efficiency half face respirator) and work clothing that does not collect dust.

More than one control will normally be required to adequately protect workers.

The workplace exposure standard

The workplace exposure standard (WES) for respirable crystalline silica (silica dust) that must not be exceeded is 0.05 mg/m3 (eight-hour time weighted average). PCBUs should keep worker exposure to silica dust as low as reasonably practicable. Air monitoring must be conducted if there is any uncertainty that the exposure standard is being exceeded or to find out if there is a risk to a worker’s health.

Health monitoring for workers exposed to crystalline silica

Under the model WHS Regulations, PCBUs must provide health monitoring for workers if they carrying out ongoing work using, handling, generating or storing crystalline silica and there is a significant risk to the worker’s health because of exposure.

The minimum health monitoring requirements for crystalline silica include:

· Medical History – collection of demographics, medical and occupational history, records of personal exposure, standardised respiratory questionnaire

· Physical examination

· Spirometry – FEV1, FVC and FEV1/FVC

· Chest X-Ray full PA view (ILO Chest Xray) (baseline and high-risk workers only) performed by RANZCR5 or is qualified as a B reader. HRCT is required in Western Australia

Symptoms of silicosis and progressive massive fibrosis may not appear for many years after exposure (workers may be diagnosed with these diseases and not present with any symptoms, even at the point of initial diagnosis), which is why health monitoring is critical. Health monitoring for crystalline silica may be required before the worker starts work so that a baseline can be established and any changes to the worker’s health after commencing the work can be detected.

Initial discussions about a health monitoring program should include:

• possible health effects from exposure to crystalline silica

• how to recognise and report symptoms

• what is involved in the health monitoring program, for example the frequency of testing and the tests that may be needed, and

• recording any previous workplace or non-occupational exposure to silica.

An initial physical examination by the registered medical practitioner should place emphasis on the respiratory system, including baseline spirometry. The spirometry should be performed as a baseline and annually in accordance with appropriate quality guidelines, so that it may be used later for comparison.

A baseline chest X-ray (HRCT in WA) should also be performed before a worker starts work in a crystalline silica process. For lower risk occupations and industries, a chest X-ray is recommended to be carried out every five years for the first 20 years of work. An abnormal X-ray, increased or prolonged exposure (above the exposure standard or greater than 20-year work history) may warrant X-rays on a more frequent basis (every three years). Where a worker has experienced very heavy exposure, annual X-rays may be warranted.

For high-risk occupations and industries, such as the composite stone industry or abnormal X-ray results a high-resolution computed tomography (HRCT) should be considered. X-rays are less sensitive in detecting accelerated silicosis.

Frequency of Health Monitoring

A Medical Assessment, Spirometry and chest Xray (HRCT in WA) should be complete as a baseline prior to the worker conducting any work with Silica.

The Medical Assessment and Spirometry should be completed annually with the Chest X-ray or HRCT scan completed every 5 years. Chest X-rays or HRCT scans may be required more frequently based on exposure levels or abnormalities found during the health monitoring examination.