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

Transcription

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 Episode 5- Kate Cole, Silica - Part 1 1

2 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 Episode 5- Kate Cole, Silica - Part 1 2

3 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 Episode 5- Kate Cole, Silica - Part 1 3

4 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 Episode 5- Kate Cole, Silica - Part 1 4

5 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. Episode 5- Kate Cole, Silica - Part 1 5

6 (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 Episode 5- Kate Cole, Silica - Part 1 6

7 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, Episode 5- Kate Cole, Silica - Part 1 7

8 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 Episode 5- Kate Cole, Silica - Part 1 8

9 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 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. Episode 5- Kate Cole, Silica - Part 1 9

10 (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. Episode 5- Kate Cole, Silica - Part 1 10

11 (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 healthrelated 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. Episode 5- Kate Cole, Silica - Part 1 11

12 (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 to scienceofsafetyanz@mmm.com. You can also contact us via that 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 enjoyed the podcast or found it informative, we would really appreciate if you can take a few moments to leave us a review as it really does help other people to find this podcast as well. And, as Willie Nelson once said, Once you replace negative thoughts with positive ones you will start having positive results. Thanks for listening and have a safe day. Episode 5- Kate Cole, Silica - Part 1 12