Sustainability in supply chains can be an awkward business if the scope of investigations ventures beyond carbon emissions or forced labour.
It’s one of the reasons the Living Building Challenge is so hard to achieve certification under, because the products in the building have to meet strict criteria on the impact of raw materials and whether they involve “Red List” substances at any point in the manufacturing process.
The Living Futures Institute defines Red List substances as those that pollute the environment, or bio-accumulate up the food chain and can reach toxic concentrations or harm construction and factory workers.
PVC is on the Red List as both a source material for Persistent Organic Pollutants and for the problematic chemicals involved in its manufacture.
- See our story The toxic face of PVC manufacturing exposed
New research by the Healthy Buildings Network, released last month, examines some of the issues at the earliest stages of PVC manufacturing and rings alarm bells about PVC product supply chains.
Stage two of its Chlorine and Building Materials: A Global Inventory of Production Technologies and Markets. Phase 2: Asia analysed the production methods of the factories supplying the lion’s share of chlorine and the PVC resin for which chlorine is a feedstock.
The Chlor-alkali factories also provide chlorine used as a feedstock for the manufacture of other products used in the building industry including epoxy, polyurethane, and polycarbonate.
HBN found the industry is thriving in China, and that many factories are co-located in the vicinity of coal mines and coal-fired power stations, due to the energy-intensity of chlorine manufacturing.
China and the United States drive the global industry, report author Jim Vallette says, accounting for more than half of the world’s PVC.
“Both countries rely upon cheap fossil fuels and toxic technologies, which are this industry’s constant companions. China relies upon massive coal-fired power plants, the ‘forever chemical’ PFAS, and toxic mercury catalysts to produce plastics. Cheap gas from fracking sites fuels the US industry, which depends upon imported asbestos to make chlorine.”
Ninety-four per cent of the Asian plants examined in the report are using PFAS-coated membrane technology to make chlorine.
Mercury is also still used, Valette says. There has been a decline in the use of mercury cell in chlorine production, however, the use of mercury catalysts in PVC production via the acetylene route used by 63 per cent of Asian plants is on the rise.
The entire PVC supply chain globally depends on at least one form of toxic technology
Valette says 100 per cent of the PVC supply chain globally depends on “at least one form of toxic technology” including mercury cells, diaphragms coated with asbestos, or membranes coated with per- and polyfluoroalkyl substances (PFAS).
In the Australian industry, the use of “best practice PVC” is acceptable under the rating criteria for tools including Green Star.
But is it actually best practice, or just less bad practice?
Teresa McGrath, HBN chief research officer, says that with current technologies employed by the PVC manufacturing industry it is “difficult to prefer one over another.”
“We encourage innovation in this industry to find solutions that don’t rely on mercury, PFAS, Asbestos or other hazardous technologies.”
There is some research momentum gathering in the safe technologies space, she says.
At this point, however, one of the most popular building materials on earth is currently responsible for a wide-ranging suite of environmental and health impacts.
Valette says that while the toll of individual plants can differ, overall industry impacts found in the research include ozone depletion through the release of carbon tetrachloride; contributions to climate change through the burning of fossil fuels to produce chlorine or to make coke for acetylene-route PVC; contamination of air and drinking water supplies; addition of bio-accumulative toxics such as mercury and organochlorine to the environment; community and worker exposure to asbestos dust from asbestos mining to supply asbestos-based chlorine production technologies; and plastic pellet and mercury contamination of waterways from the dumping of chemical plant wastes.
The solution is not necessarily just going PVC-free
McGrath says simply going PVC-free for projects is not the optimum solution, as “single attribute” approaches such as “PVC-free” can lead to “regrettable substitutions” unless the substitutes are fully investigated.
“Best practice would be to use products that are free of PVC for which full disclosure is available and for which all materials have been reviewed for hazards at all steps of the product’s life cycle,” she says.
“This is a high bar, for which few products comply.”
HBN offers a Hazard Spectrum guide for choosing better products that have reduced impact, as until there are more truly safe products in the market doing less bad is possibly the best alternative for specifiers.
While Environmental Product Declarations have become a go-to tool for assessing the credentials and impacts of products, Valette says that he has not seen the impacts of the resins used in product manufacture disclosed in any building product transparency document, including EPDs.
However, they are still valuable, he says.
“Such declarations as EPDs, Health Product Declarations and other forms of product transparency are essential information, especially given the stakes at play here.
“For example, some of the resins are coming from the Xinjiang Uyghur Autonomous Region of China, where giant new plants use mercury and coal to make PVC.
“These plants, run by the government of China, are also located in the heart of the region where the government is forcing hundreds of thousands of local people, Uyghurs, into so-called ‘reeducation camps’.”
“Flooring made from these plants’ resins are in global commerce.”
Valette says designers, specifiers, and builders might want to know if a material they are using has supply chain links to that region.
He also sees a role for pressure from product users in encouraging manufacturers to be more transparent about plastic resin origins.
“Manufacturers know where their plastic resins come from. If they claim not to know, our inventory provides them with plenty of information for them to start with to figure it out.”
The link between coal-fired power and PVC production is concerning from a carbon footprint point of view. The Fifth Estate asked Valette if there is any evidence of manufacturers switching to renewable energy.
He says he has not seen any evidence of renewables as an option in any of the Asian or US plants.
“Coal-fired and gas-fired plants dominate, and there appear to be no moves to minimise this dependence. Carbon footprinting of PVC usually does not account for the industry’s growing dependence on coal.”
There are some Lifecycle Assessments that assume all the power consumed is gas-fired, he says.
“This is hardly the case for the growing share of PVC resin made in interior China, which depends upon massive coal-fired power plants, and consumes coke in the acetylene-based [vinyl chloride monomer].
“LCAs, which form the basis for so much assessment of PVC’s place in the built environment, are badly outdated and incomplete in their input assumptions.”
He says the PFAS-coated membrane technologies have been promoted in some quarters as an energy-saving approach.
“But those savings are minimal compared to the overall impact of choosing, say, vinyl over locally-sourced wood products for a construction project,” he says.
And the technology relies on PFAS, which is problematic from a legacy pollution perspective.
Australian vinyl industry responds
Chief executive of the Vinyl Council of Australia, Sophi MacMillan, disputes the report and some of its key findings.
She says HBN’s research project is not peer reviewed and “appears to contain numerous factual errors as well as virtually ignores the production of caustic soda.
“It’s a deliberate attempt to mislead and its conclusions are highly, and wrongly, skewed for it to have any credibility.”
MacMillan points out that the plants using the membrane technology are chlor-alkali plants that produce roughly equal amount amounts of chlorine and caustic soda by passing a current through salt.
“It is not currently possible commercially to produce one without the other,” she says.
“If you stop chlorine production, you stop caustic soda production,” she says.
Caustic soda is itself a key feedstock for multiple industries, including aluminium production, paper products, textiles, dairy industry and many others.
Chlorine is used in multiple industries also, including PVC, pharmaceuticals, disinfection and water purification. Less than 40 per cent of the world’s chlorine production is used for PVC production, MacMillan says.
She says that 99 per cent of China’s chlor-alkali production is using membrane technology.
But coal can’t be disputed
The role coal plays in the supply chain she does not dispute.
“China produces PVC by one of two routes: ethylene, the dominant production method in the US, Europe and the rest of Asia; or using coal to produce acetylene,” MacMillan explains.
“Ethylene is reacted with chlorine to produce vinyl chloride monomer (VCM), the precursor to PVC. Acetylene is reacted with hydrogen chloride to produce VCM.
“Because of China’s abundance of coal, today, 80 per cent of PVC produced in China is via the acetylene route. Apart from one small acetylene plant that was operating in India, we are not aware of any other such plants elsewhere in Asia.”
She says chlor-alkali producers need to balance caustic soda demand with chlorine demand, and that in China it is aluminium production for downstream aluminium products that drives the production at chlor-alkali plants, not PVC production.
“Although demand for PVC in China has seen steady growth over recent years, overall demand for chlorine has been flat over that time, leading to an imbalance in the chlor-alkali sector. Like elsewhere, PVC is in effect a ‘sink’ for some of the chlorine produced.”
She says that in Australia the industry wholly discourages the use of the coal-intensive acetylene-route PVC.
The VCA’s PVC Stewardship Program requires signatory companies including local manufacturers and importers of finished products to meet stringent VCM-PVC manufacturing requirements including confirmed avoidance of any use of mercury in the process.
Signatories have to seek relevant information from their supply chains to demonstrate this and are regularly independently audited by a third party to verify this.
“Best Practice PVC accreditation sets the same standards and gives specifiers confidence that these accredited products have avoided mercury in their supply chains. We know which plants in China are ethylene-route PVC.”
To the best of the VCA’s knowledge, no acetylene-route PVC is used in Australian manufactured PVC products, MacMillan says.
MacMillan also questions whether PFAS chemicals are a factor. Her understanding is that the membrane technology for chlor-alkali plants uses per-fluorinated polymers reinforced with polytetrafluoroethylene (PTFE).
This substance is also the one found in brand-name products such as Gore-Tex and Teflon, she says.
It should not be confused with the Stockholm Convention-listed PFOS (perfluorooctanesulfonic acid) and its salts and perfluorooctanesulfonyl fluoride (PFOSF) used in products such as firefighting foams and fire retardants.