July 17, 2019 Andrew Watters

A Safe Work Procedure for Respirable Crystalline Silica (RCS)

Whether you know it as RCS, Silica Dust, Crystalline Silica or Respirable Crystalline Silica - this stuff is nasty! It's a hazardous agent and has received a renewed focus of late. In response, we've made changes to 21 of our SWMS templates. If you've purchased any of these in the last six months, you'll have received free upgrades by now. Let's look at this 'nasty' and learn what we can do about it.

Respirable Crystalline Silica is 100 times smaller than a grain of sand. That's less than tiny! You could inhale a bucketful and not even know it. If you're around it for a long time or experience a high level of exposure, the effects can be devastating - even deadly.

Crystalline Silica is serious! Severe enough in fact, that wherever there’s a risk of exceeding exposure limits, WHS Regulations require air monitoring every 12-18 months. The limit is a minuscule 0.1mg/m3 (averaged over an eight hour day). That’s like covering a 5 cent coin with dust, shaking it from side to side and measuring the thin covering that’s left behind.

Air sampling, of course, only tells us there’s a problem. Like the proverbial smoking gun, it only lets us know something terrible has already happened. From a proactive WHS stance, much more is required.

In this article, we'll take a look at:

The nature of Silica dust.
How much silica dust is harmful.
Silicosis and other incurable diseases.
Safe Work Procedures.
SWMS templates relevant to Respirable Crystalline Silica.

What is Crystalline Silica (a.k.a. Silica Dust)?

Crystalline Silica is best known as Silica dust. You'll encounter it in many building and construction materials; including gravel, sand, stone, rock, concrete, tiles, bricks and even some plastics. It comes in a variety of forms, though the most common is quartz.

Silica dust becomes a problem when released into the air, at which point we refer to it as "respirable crystalline silica" or RCS.

You or your crew are at risk if required to

Load, crush, haul, chip, hammer, drill or dump rock or concrete;
Chip, hammer, drill, saw or grind concrete or masonry;
Dry sweep or air-blow concrete or dust;
Jackhammer a variety of materials;
Remove paint or rust with power tools;
Use abrasive blasting techniques; or
Grind mortar.

Every exposure is significant and cumulatively toxic. Silica Dust is a stealth killer that does not provide a warning, announce its presence, discriminate or negotiate.

It's wise to be proactive and maintain a vigilant and healthy fear.

How Much Silica Dust is Harmful?

Exposure does not guarantee that cancer or other conditions will develop; however, your risk factors increase substantially with:

Exposure over a protracted time, or
Repeated high-level exposure.

So, how much silica dust is harmful? The most accurate we can be is this: if lungs are exposed to this substance at anything more than minor and irregular instances, it can be harmful.

Just how harmful? Identified injuries and diseases include:

Silicosis (irreversible scarring and stiffening of the lungs),
Chronic Obstructive Pulmonary Disease,
Kidney disease, and
Lung Cancer

How Much Silica Dust Causes Silicosis?

Silicosis is the most well-known consequence of Silica inhalation. It’s no surprise then that people ask, ‘How Much Silica Dust Causes Silicosis?’

Most of us like to know how much of something we can get away with. However, Silicosis isn’t like that.

It’s a mongrel disease that causes the lungs to stiffen as they are irreversibly scarred. Breathing becomes impaired and the accompanying cough, phlegm build-up, weight loss, fatigue, chest pain and fever can be personally crippling.

Typically, Silicosis develops after 10 or more years of low-level exposure, but accelerated instances have been recorded. There have even been cases reported within weeks of an intensive exposure.

We’ve already mentioned WHS regulations consider 0.1mg/m3 to be harmful. It’s also worth remembering how tiny an amount this is; cover a 5 cent coin with dust, shake it from side to side and then measure the dust left behind. That’s all we’re talking about!

So how much Silica Dust causes Silicosis? We don’t know! What we do know is this: we need to be very, very careful.

Lung Disease

Chronic Obstructive Pulmonary Disease (COPD) is linked to Crystalline Silica intake. COPD brings on shortness of breath, chronic coughing and wheezing as a progressive lung condition. Sometimes COPD takes the form of Emphysema, Chronic bronchitis or Chronic asthma.

COPD is progressive and incurable! That means it keeps getting worse and it doesn’t go away. You can survive with it and manage it, but life is most certainly better without it.

Kidney Disease

Silica Dust has also been identified as a contributory factor in Chronic Kidney Disease (CKD). CKD can result in nausea, vomiting, fatigue, sleep problems and confusion. These can, in turn, lead to the complications of heart disease, anaemia, blood pressure and bone disease. If you like to learn more about the CKD links, the US National Institute of Environmental Health Sciences report makes confronting reading.

Cancer

The International Agency for Research on Cancer (IARC) conducts operations on behalf of the World Health Organisation (WHO). It lists Silica as inorganic dust, in the same grouping as asbestos, while also classifying it as a "prioritised occupational carcinogen".

In 2012, the IARC estimated the proportion of the Australian population occupationally exposed to Silica. They place this figure at 11.7% of workers, or 586,890 people (1). That's almost six Melbourne Cricket Grounds packed to capacity or just a few thousand less than the population of the Gold Coast.

Of these persons, the Cancer Council estimate that occupational Silica exposure causes 230 people to develop lung cancer each year (2).

This is not something to be taken lightly!

Crystalline Silica and Safety

Many workers are exposed to Silica, especially those in the mining, construction and engineering industries - but quantifying safe versus unsafe exposures is very difficult. It's better to assess your exposure and employ safe work procedures to reduce airborne interactions.

Rather than ask 'how much' silica dust you can safely be exposed to, it's better to assess how often you interact with RCS, then identify safe work procedures that can reduce the intensity or frequency of exposure. Preferably, you should reduce intensity and frequency.

We can't say how much Respirable Crystalline Silica is safe. Health authorities are seemingly saying a safe level of silica dust exposure does not exist. Limits for silica dust exposure are currently set at 0.1mg/m3 (averaged over an eight hour day), but there are recommendations for this to be dramatically reduced to 0.025mg/m3.

Is There a Safe Work Procedure for RCS?

Silica dust is harmful! Ideally, our WHS goal would be to eliminate the hazard. In this case, that’s simply not possible. It's seemingly impossible to stop producing it.

Therefore, the four safety control considerations are:

Respirators,
Materials,
Dust control, and
Clean-up.

Respirators

Personal protective equipment (PPE) includes respirators with at least P2 filtration, fit tested to each worker. We mention Respiratory Protective Equipment (RPE) first, not because it should be the primary means of control. Instead, combine it with higher order controls such as local exhaust ventilation, water suppression and isolation (explained below).

Employers must ensure all workers are issued with and wear PPE as required. They must train their team in its use, fit test the equipment and ensure pre-use inspections take place.

Materials

When it comes to products and materials, always check the manufacturers' Safety Data Sheets (SDS). Be especially aware of recommendations about RCS.

Dust Control

Consider the following dust control strategies (which you'll also find detailed in our SWMS template solutions):

Use on-tool dust extraction (including Local Exhaust Ventilation (LEV) where possible;
Employ water suppression methods. Use wet cut methods for brick, tile, stone and concrete; and
Isolate RCS work activities away from other workers. If indoors, separate RCS work activity with floor to ceiling plastic sheeting.

Clean-Up

When it comes to cleaning up dust and debris that contains RCS, you should NOT dry sweep. Instead, you can:

Wet sweep,
Hose down,
Wipe,
Mop, and/or
Vacuum.

Note that your vacuum cleaners must be of M or H Class industrial standard (per AS/NZS 60335.2.69).

Finally, you should double bag any RCS waste and debris before placing in the bin or skip. Remember that others are yet to encounter that waste.

Is There a SWMS Template for Respirable Crystalline Silica?

We provide 21 Safe Work Method Statement templates that deliver safe work procedures for common work activities and equipment where RCS dust is a common hazard.

We’ve revised and improved these SWMS templates with enhanced safety controls. The links will take you to the information page for each SWMS.

Silica Dust is Harmful. What Can We Do?

We asked, ‘How much silica dust is harmful?’ and more specifically, ‘How much Silica Dust causes Silicosis?’

We found the answers were a disturbing ‘Not Much’.

As an airborne substance that is less than 1% of the size of a grain of sand, it is a 'Ninja stealth' irritant that can lead to permanent disability or death! However, it doesn't have to happen.

Considered as a whole (though controls do vary from one SWMS template to another) this usually involves implementing respirator, material, dust control and diligent cleanup controls. We've explained these at an introductory level and also made the SWMS templates available to you.

Elimination, substitution, isolation, engineering or administration controls are ineffective. Hazard reduction through safe work procedures, therefore, is the best you can do - but if done well, it should be enough!

If you'd like to learn more about Respirable Crystalline Silica (RCS), there is an excellent PDF resource available from the Cancer Council.

If you'd like to remediate the problem in your workplace, either follow any of the SWMS template links provided above, call us on 1800 304 336, or request a call back by using the on-site contact form. Silica dust problems manifest differently according to the workspace, but you can effectively manage the problem. Whether asking a question or purchasing a solution, I look forward to your call.

References:

Occupational Exposures to Carcinogens in Australia (2012) Cancer Council of Western Australia. 3, 8 and 9
Workplace Cancer, The Cancer Council.

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