3m transcript for the following interview: ep-5-kate …...episode 5- kate cole, silica - part 1 1...

Episode 5- Kate Cole, Silica - Part 1 1

3M Transcript for the following interview: Ep-5-Kate Cole, Silica Part 1

Mark Reggers (R) Kate Cole (C)

Introduction: The 3M Science of Safety podcast is a free publication. The

information presented in this podcast is general only, and you should always seek

the advice of a licensed or certified professional in relation to your specific work or

task.

Welcome to the 3M Science of Safety podcast presented by 3M Australia and

New Zealand Personal Safety Division. This is a podcast that is curious about the

signs and systems of all things work, health and safety, that keep workers safe and

protect their health. I am Mark Reggers, an occupational hygienist, who likes to

ask the questions Why, How, and Please Explain. Whether you are a safety

professional, occupational hygienist, or someone with any level of WHS

responsibility in the workplace, maybe you are a user of safety products or maybe

you are a bit of a safety nerd who finds this stuff really interesting, then this is a

podcast for you.

(R) Today we are talking all things silica with Kate Cole. We had a fantastic

conversation with Kate and it went for quite a while because it is a fair bit of

information, so we have decided to split it into two parts, and this is part 1 of that

conversation with Kate Cole. Enjoy!

Today we have Kate Cole from Ventia talking all things silica. How are you, Kate?

(C) I’m great, Mark, how are you?

(R) It’s a fantastic day today, I get to talk to you all things silica which, for you

know, a safety nerd and occupational hygienist that sounds interesting. Kate is a

certified occupational hygienist who has worked in the construction industry for


almost two decades on projects in Australia, Hong Kong, and the USA. She holds

degrees in Science, Engineering, and Occupational Hygiene, and works on major

projects involving complex contaminant land remediation and large scale

underground tunnelling. She is currently the manager of occupational health and

hygiene with Ventia. Kate works across most tunnels under construction in

Sydney. She is currently supporting transport for New South Wales on Australia’s

largest public transport infrastructure project, the Sydney Metro, as the

occupational health and hygiene manager. So, you’re the manager of two things,

Kate, is that right? Am I reading that right?

(C) Yes, very capable, very busy.

(R) Very busy, I can only imagine. One last thing about Kate which I think is

interesting, so I am going to ask her a little bit later about it. In 2016 Kate was

awarded a Winston Churchill fellowship where she visited numerous tunnel

constructions projections in Norway, Switzerland, the UK, and the USA to

investigate best practice to prevent illness and disease in tunnel construction

workers. How was that trip, that would have been a fairly big one?

(C) Oh, the Churchill Fellowship was absolutely amazing. It was great to go and

see how other countries and other organisations tackled the key issue of silica dust

control in the really high-risk cohort that we have.

(R) I have a couple of questions a little bit later once when we get to it, what are

your learnings from there, but [K: Don’t get too excited] I won’t get too excited, we

are talking about silica, and I know it is a very exciting topic. So, let’s start right

with the basics. What is silica?

(C) Well, silica is the term commonly used to describe respirable crystalline silica.

And when we talk about silica or silica dust, we are referring to that really, really


fine dust that is generated from many different types of activities, and it is called

silica dust because it mainly consists of quartz or has quartz in that really fine

respirable dust.

(R) So different types of rocks. Are there different amounts of silica, or it is always

a set percentage of silica…?

(C) Definitely, different types, so in Sydney particularly is quite pertinent, where we

are today, so Sydney sits on a bedrock of Hawksbury sandstone and there is shale

on top of that, and shale typically has around 30 percent quartz in it, so if you cut

or rip into shale then you’re going to generate silica dust, but more concerning is

Hawksbury sandstone, because Hawksbury sandstone has over 75 percent quartz,

and in some cases, it is closer to the higher 90 percent, so any type of disturbance

of that rock, whether it is tunnelling or cutting or ripping or crushing the sandstone

you are going to be generating quite significant proportions or concentrations of

silica dust.

(R) So, all those tunnelling projects that you’re working on and around, that is going

to that Hawksbury sandstone, that 70 to 90 percent sandstone? Or …

(C) Yeah, it is, and that is why it is a key area focus for the tunnel construction

industry. But that’s not the only industry where you come across silica dust, so

kitchen benchtop manufacture is quite pertinent, because especially with

countertops and engineered stone, they will have quite high proportions of quartz,

as opposed to I guess your traditional marble which has a really low proportion of

quartz, you might only have like 2 percent in marble, whereas engineered

countertop benchtops might have over 90 percent, so it is a really big difference.

And the construction industry in general comes across silica dust quite a bit, with

concrete and cement containing anywhere from you know, 15 to 30 percent


quartz, so any type of concrete work for shotcrete, that is where you will find quite

a bit of silica dust in the air as well.

(R) You just think about concrete, I mean every building has a level of concrete,

driveways, homes, I guess that is a fairly standard activity across all industrial and

non-industrial places frequently.

(C) Definitely, and my main background is in construction, so as you can imagine,

for myself and other occupational hygienists in construction, silica dust exposures

form a key area of focus for us in this industry.

(R) I can imagine. So, you mentioned respirable crystalline silica, so the really fine

stuff, are there other different types of silica?

(C) There are, so silica also refers to amorphous silica. Amorphous silica is a lot less

toxic when we are looking from an occupational hygienist perspective, we are

looking at protecting worker health, we are really looking at the respirable

crystalline silica, so the quartz type of silica rather than amorphous silica.

(R) So, you mentioned construction. What about quarrying slate, are there are any

sort of other industries other than the ones you have mentioned so far that people

should be aware of if they are not aware of?

(C) Yeah, so in addition to those, so ceramic manufacture, brick and tile

manufacture, foundries, and just being in Sydney and walking through The Rocks or

walking through any beautiful heritage area, you will pretty quickly see just how

many of our buildings are constructed from that gorgeous sandstone, which is

beautiful to look at, however it can be quite hazardous to maintain, with tuck

pointing and cleaning of that type of sandstone. They represent really key tasks


that we would be looking at to make sure that we control those exposures as far as

reasonably practical as much as we can to protect the health of those workers.

(R) So, I guess it is not the, you can try to maintain some of those buildings, it’s not

like you can get up there with some Scotch Brite or something and just sort of wipe

it off [K: No] or scrub it off, we’re talking fairly…

(C) Preferably not

(R) ...abrasive…actions to maintain those, it is a fairly good point, not just the

construction but the maintenance of those particular buildings.

(C) Definitely.

(R) What are some of those activities. You mentioned some of the industries, what

about the actual activities, now we spoke about you know, maintaining, so maybe

blasting, what are some other activities that people should be aware of?

(C) Um, I think one of those most common ones we see is when we’ve got workers

who are doing any kind of hand-held polishing or hand-held grinding activities, and

also concrete saw cutting activities, whether that is in a road or a wall or any time

of hand-held tool that cuts rock or stone is a key risk area, and something that we

really need to focus on. How do we control the dust that comes out of those

activities, and recognising that it is not just dust, and you are probably used to

seeing dust in the construction industry, this is probably not something new, but

however the dust that is coming from concrete and sandstone and other sorts of

rocks does have really high proportions of silica in them. See we just have to be

conscious of that when we are looking at those types.


(R) So, you mentioned about dust and construction projects, and you know, you’re

driving along, and you see the dust, can you see the silica in those dust clouds? Is it

I see dust, that is absolutely going to have silica in it?

(C) Well technically no, you can’t see respirable crystalline silica because it is so

small, and I mean we are talking about dust that has a, not to get too technical, but

a median cut-off point of 4 microns, so this is very, very small. However, that sort

of dust isn’t just there by itself, it is normally co-located with big chunks of other

dust that you can see, so if you do see workers covered in a cloud of dust and the

dust is made up of sandstone dust, or concrete dust, then it is reasonable to assume

that that dust contains a pretty big proportion of respirable crystalline silica.

(R) As you said, you can’t see it, so it can’t be seen by the naked eye, so you’re not

going to rely on Oh, I’m pretty sure it’s not going to contain it, but I guess that is so

crucial I guess from a workplace point of view trying to identify, maybe we’re

cutting into that particular type of sandstone, what is going on there.

(C) Yeah, and that brings up a really good point about if you are a PCB or you are a

particular organisation that is doing or in charge of these particular activities, really

understanding what the inherent amount of quartz C is in the products that you are

using, so that is really from an occupational hygiene perspective, what we would

call hazard identification. So silica is difficult, I think, because you are not bringing

on a substance to your work site that has come in with a safety data sheet, you are

not bringing it on, you are actually generating it, and that in itself can be tricky

because the level of aware of, well, how much silica is in this product that then I am

cutting into, can be kind of mixed in construction. In some areas, there is a really

good level of awareness, and I will use tunnel construction as an example, a really

good level of awareness of the risks associated with crystalline silica and the level

of control that is needed. Then in other areas of construction, and particularly in

some, say, small businesses that may not have the funds or ability to have great


access to occupational hygienists and those types of technical experts, and the

level of awareness can be a bit less. So what those businesses can do is start to

have a look at, well, how much quartz do I have in the stuff that I am cutting into,

and what is in the cement that I am using, and what are some practical control

measures that I can put in place so that I don’t have to rely on the ability to see it to

actually control it.

(R) That’s a great point, I mean the basis of any risk assessment, whether you’re a

hygienist or a …… professional - what are we doing, what have we got, and what

are those particular things we may be generating as well. Are there other things in

the workplaces that may be causing exposures? I mean obviously we know we’ve

got our concrete, we’re cutting it, but there are there things that other people may

not be on the actual saw who may be getting exposure that workplaces should be

maybe thinking of considering?

(C) We would classify it in two ways, as a hygienist we look at primary exposure

and secondary exposure. And we look at secondary exposure, that is where you

are not necessarily generating the dust, but you just happen to be in the location

where unfortunately you are being exposed. That is one of the most common

types of exposures in construction, and I guess a really good example would be

what is termed a spotter. So, a spotter is generally a worker spotting a piece of

plant doing something, so making sure that people don’t come into that area for

example, making sure that there is, you know, a good level of area of separation

between a piece of plant and another piece of plant, or may actually be holding

some form of dust suppression to suppress the dust. And by the very nature of

what they are doing typically, they are using hoses like a high-pressure hose or

garden hose or any time of hose that’s got big water droplets, generally they are

not actually reducing exposure to silica. Because silica is really, really fine, and so

you need a really, really fine water droplet size that matches that same size of dust

to knock it out, but unfortunately those spotters, if they are using a garden hose,


are really just being put in a location where they are being exposed to really high

concentrations of dust, even though they may feel or think that they are actually

suppressing it using the tools that they have been given. So that is a key area that

we see a lot where those spotters are actually exposed to very high concentrations

of silica because of the nature of where they need to stand to do that particular job.

(R) So, the effectiveness of their control, their water, is really controlling that

secondary exposure you mentioned for all other people, you may be a visitor on

that site, you may be someone working in the office, whatever it may be, so that is

another key control point there. So, you have all these dust clouds, with lots of

silica in it, how much silica will cause harm to a worker, or is it a one-off exposure,

are we talking it takes time to have this particular negative health effect that we’re

going to ask you about a little while?

(C) Well, it is a chronic acting health hazard, but is also a carcinogen, so to be

honest, exposure to carcinogenic agents should be controlled, so far is reasonably

practicable, we shouldn’t be relying on a workplace exposure standard, and I use

that term, it is a legal term, it is referred to in the Work Health and Safety

regulations. The Workplace Health and Safety regulation has a workplace

exposure standard for respirable crystalline silica, and that is 0.1 mg per cubic

metre which is over an eight-hour shift. That may not be much to listeners, but to

try to put it into a visual perspective, imagine you have a 5-cent coin in front of

you. 0.1 mg per cubic metre is around a small piece of dust, it is a really, really

small amount that workers shall not be exposed to above that limit over their

working day. However, that doesn’t mean that you’re allowed to expose them to

just a little bit less than that. Crystalline silica is carcinogenic. We need to make

sure that we are controlling exposure as far as reasonably practicable, as low as

possible, and it is a chronic acting health hazard. That means that the more you are

exposed to it over a longer period of time that the higher your risk is of developing

illnesses associated with silica dust, and these aren’t small illnesses, these are


irreversible occupational lung diseases which are absolutely debilitating, like

silicosis and lung cancer and in addition to other things like renal disease, etc, so

this is incredibly important. And you will probably say, well, I drive past lots of

construction sites and I see these dust clouds all the time, and I guess that is

something that we hear as occupational hygienists quite a lot, but just because it

might be quite common to see it does not mean that it is acceptable, and it doesn’t

mean that we can’t change and do something about it.

(R) So that 0.1 mg per cubic metre, that workplace exposure standard here in

Australia, now you’ve done a bit of traveling with your fellowship, is that consistent

with other levels around the world, as obviously every country has different

exposure standards?

(C) Well interestingly no, it’s not. So, the US OSHA recently brought out their new

silica rule and what that did, amongst many other things, was reduce their

workplace exposure standard to essentially half of Australia’s workplace exposure,

to 0.05. Also, there are other groups in the US such as the American Conference

of Governmental Industrial Hygienists, the ACGH, so they have recommended the

threshold in a value or the equivalent of the workplace exposure standard to be

around a quarter of what we have in Australia. And, you know, some may say well

these are just numbers, what do these mean, and essentially it shows that other

countries internationally have really focused on the issue of respirable crystalline

silica and started to reduce the limit as more scientific evidence has become

available. However, in Australia our Work Health and Safety regulation doesn’t say

it is okay to expose people to 0.1, it really requires us to control exposure so far as

reasonably practicable and that is the maximum limit, so even though we might be

at 0.06 or 0.07 or 60 to 70 percent of our limit, it doesn’t necessarily mean that

that is okay if there are reasonably practical measures that can be put in place to

reduce it even further.


(R) Because those exposure standards are not lie in the sand, safe, and unsafe, and

that is because I guess people who are health and safety professionals would say

oh, we’re underneath that number, well, you could still get lower than that and that

is going to be a way better outcome for the workers than saying all right, we’re at

50 percent, that is acceptable, let’s go on to our next priority.

(C) And to put that into perspective, when OSHA did publish their silica rule, they

published a whole bunch of amazing documentation to support it, and one of those

involved a quantitative risk estimate of the actual new rule, and to summarise many

hundreds of pages into one key thing, it would be that the risk of developing this

incurable occupational lung disease silicosis at the current workplace exposure

standard in Australia has been quantitatively estimated to be anywhere between 12

to as high as 77 percent of workers if they are exposed to the current exposure

standard over their working life. That is a big variation, so I don’t think 77 percent

is acceptable, nor do I think that 12 percent is acceptable, but it just shows you that

wide degree of variation, and actually reducing exposures, all that will do is reduce

those numbers which is what we want to achieve.

(R) Do you think Australia will follow suit, so usually we sort of, when global trends

are happening, and not just in health and safety spaces, do you think Australia will

sort of lower that exposure standard sometime in the future?

(C) Well, I do know that Safe Work Australia are currently in the process of

reviewing the Australian Workplace Exposure Standards, which is great. However,

a standard, to be honest, is just a number if there is no compliance with that

number. And I think as an industry, and if I look at the construction industry

particularly, we would be better spent really pushing for better compliance with

our existing exposure standards rather than trying to lower a number that may not

even be able to be complied with.


(R) I think it is a fantastic point, you can lower the numbers as much as want, but

the focus has got to be genuinely controlling the hazard, and that can be done right

now irrespective of whatever number is out there in that workplace exposure

standard.

(C) Yes.

(R) You mentioned silicosis before, so I am assuming that is one of those health-

related diseases that silicosis cause, can you expand on what silicosis is, and any

other particular disease that may be caused by respirable crystallised silica.

(C) Well silicosis is an occupational lung disease. There are a few different types,

so there is chronic silicosis which you can get after about 20 years of exposure

also, or the latency period I should say is around 20 years after exposure. There is

accelerated silicosis, and that comes from very high exposures to silica dust, and

unfortunately in Australia we have actually seen some recent cases of accelerated

silicosis in kitchen stove top manufacture workers where they are exposed to really

high concentrations because of the high proportion of quartz in those benchtops.

And there are other diseases that are caused from exposure to silica such as

chronic obstructive pulmonary disease, commonly known as COPD, in addition to

lung cancer and also renal disease as well.

(R) Just going back to that silicosis, so essentially the amount of dust, the more that

you are breathing in the faster you are going to see those particularly health

effects, the shorter the latency period, so once again, coming back to doing as

much as you can to control it as low as reasonably practical. So, it seems that we

are saying, if I can summarise, the health risks I guess associated with crystalline

silica are significantly lowered, the lower the dust that people are breathing in, i.e.

the controls you are putting in.


(C) Yes, so the lower your exposure to silica dust, the less your risk of developing

disease associated with silica exposure. So, less silica dust exposure, less chance

of developing silicosis.

(R) That is part 1 of my conversation with Kate Cole around silica. Make sure you

download the next episode when that is released to listen to part 2 as well. If you

have any questions, comments, suggestions for any future topics or guests you

think we should get into the studio, you can send us an email to

[email protected]. You can also contact us via that email if you need

any help around RPE, respiratory protective equipment, around silica, or any other

PPE, we can come out to your workplace and give you a hand as well. Be sure to

subscribe to the podcast through ITunes or wherever you get this podcast from so

you don’t miss any future podcasts including part 2 of my chat with Kate. If you

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this podcast as well. And, as Willie Nelson once said, “Once you replace negative

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listening and have a safe day.

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3m transcript for the following interview: ep-5-kate …...episode 5- kate cole, silica - part 1 1...

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