Dust won’t settle on quarry spat
"Our community is not comforted by their unproven assurance . . .'' Templeton Residents Association chairman Garry Kilday
Health-and-safety bosses in the quarrying industry have dismissed fears among people living near sites around Christchurch about a potentially lethal disease arising from dust.
Residents in Yaldhurst have long voiced concerns about silica dust, a byproduct of quarrying that can trigger pulmonary issues, the lung disease silicosis and, rarely, cancer.
Scores have complained that dust from quarries has coated their homes, with a number taking to wearing masks to protect themselves.
Some have claimed they have developed breathing problems, with symptoms similar to silicosis.
But MinEx, the health and safety council for the mining and quarrying sector, has dismissed those concerns, saying testing near Canterbury’s quarries has found no evidence of respirable crystalline silica (RCS) – tiny particles of silica dust – at levels that can cause harm.
Chief executive Wayne Scott said: ‘‘New Zealand’s limit on RCS is 0.1mg per cubic metre. Any risk of RCS exposure is to quarry workers, not neighbours who most often are hundreds of metres from a quarry face with a huge amount of air space between them.
‘‘MinEx is currently working with WorkSafe to continue reducing any risk to quarry workers.’’
But residents in Templeton fighting the planned development of a new quarry on their doorsteps by construction company Fulton Hogan say they take no comfort from the ‘‘unproven assurance’’.
Environment Canterbury (ECan) is monitoring a number of sites in Yaldhurst for silica dust following a year of concerns from residents, with the first results expected next month.
Two independent tests carried out a year ago – one commissioned by residents, the other by ECan itself – have already found dust on people’s homes contained 30 per cent silica.
But Scott has suggested some people are ‘‘talking up’’ risks of RCS.
He said: ‘‘We’ve seen a toxicology professor being at pains to emphasise the low chances of developing silicosis from quarry dust and medical authorities saying testing to date at those Canterbury quarries at the centre of dust concerns shows no RCS level which is remotely likely to cause silicosis.
‘‘We need to dispel some of the myths that are emerging which suggest quarry dust is laden with RCS.
‘‘Another round of monitoring is being undertaken by ECan at some Canterbury quarries which by mid-year I expect to confirm that RCS is virtually undetectable and no serious health risks arise.
‘‘Meantime, while acknowledging many quarries have good dust management in place, some quarries have to continue to lift their game because any dust that emerges from a quarry – as from any farming or earthmoving operation – is annoying to close neighbours.’’
It is thought there has never been a case of a member of the public developing silicosis from quarrying in New Zealand.
Professor Ian Shaw, a toxicologist at the University of Canterbury, says that while there is ‘‘no question’’ breathing dust poses health risks, the chances of developing silicosis or serious long-term health problems from quarry dust are low and would require prolonged exposure.
Speaking previously about the Templeton proposal he said silica dust was a ‘‘key health concern’’, with the likelihood of siliceous dust getting into the air from quarrying being ‘‘very high’’.
But he said yesterday: ‘‘If the RCS levels are below statutory limits the risk of harm is very low indeed (there is never ‘no risk’).
‘‘I also agree that the risk would be for the workers because they would likely be exposed to higher RCS levels and that this should be dealt with by appropriate protective gear or, better, by minimising dust production.
‘‘It seems to me that the residents are annoyed by the dust, as I would be, but that the RCS levels are not likely to cause long-term health issues because exposure levels to RCS are too low.
‘‘It might be that breathing airborne dust causes irritation, but that this will not lead to the long-term effects they fear, such as silicosis.’’
Dr Alistair Humphrey, Canterbury medical officer of health, agreed with MinEx that it would be ‘‘extremely unusual’’ if monitoring found levels of RCS likely to cause silicosis.
But he suggested New Zealand’s laws, which do not stipulate a minimum distance for quarries to be set back from houses, allowed a greater chance for people to fall ill.
And he urged MinEx to share any data it had proving RCS levels in the area are not a problem.
He said: ‘‘While [silicosis] is widely recognised as an occupational disorder and there are very few scientific papers that have ever identified it in the general public caused by mining or quarrying, it has happened on rare occasions.
‘‘There are reports from India – not from OECD (Organisation for Economic Co-operation and Development) countries, but most OECD countries have a setback distance.
‘‘If you’ve got a quarry across your back fence, arguably you’re getting a similar exposure to someone who’s working in the quarry, and arguably you’re getting more because you’re there 24/7, whereas they only come in for an eight-hour shift.’’
Residents in Templeton, some of whom could see a quarry built just metres from their homes, say they find little comfort in MinEx’s reassurances.
Garry Kilday, chairman of the Templeton Residents Association, said: ‘‘MinEx is the paid health and safety organisation for the quarrying industry.
‘‘Our community is not comforted by their unproven assurance that silica dust, proven to cause irreversible lung cancer, has no evidence of harm to us. They have not dismissed our fears. We would be more comforted by positive evidence that silica dust from quarrying activity will not harm our diverse community. They have not said that, and won’t. Our people are elderly, young, well and some (are) unwell. Some will be more susceptible to risks than others.
‘‘Fulton Hogan and the quarrying industry should not be allowed to continue to gain immense commercial profits from activity that harms our people.’’
Brian Roche, chairman of the Aggregate and Quarry Association, which represents about 85 per cent of New Zealand’s production of aggregate, said most of its members actively managed dust through watering roads and stockpiles and washing vehicles.
He said: ‘‘All quarries have to meet dust limits set by councils as part of a resource consent. Most modern quarrying operations also minimise noise and traffic movements, working in with neighbours and councils.’’