Plastic not so fantastic?
PVC has been condemned as the “poison plastic” by the green lobby yet is still in incredible demand.
Polyvinyl chloride (PVC), or simply vinyl, is a hugely versatile plastic widely used in the building industry. It is used for windows, doors, cladding, guttering, conservatory roofs, electrical wire insulation, floor coverings and a host of consumer products. The arguments for PVC are that it’s extremely durable, inexpensive, lightweight, low-maintenance and corrosion resistant. So, what’s not to like?
PVC has come under fire for posing serious threats to human health and the environment. Dubbed “the poison plastic” by Greenpeace, PVC has been slammed for releasing toxic chemicals during production, use and disposal while contributing to the planet’s growing plastic pollution crisis and global warming.
What does the ‘u’ stand for?
Attempts were made in the early 20th century to use PVC in commercial products but were thwarted by difficulties using the white, brittle material. It wasn’t until the late 1920s that a method was developed to plasticise PVC by blending it with various additives. The result was a more flexible and more easily processed plastic resin.
PVC comes in two basic forms: rigid and flexible. The rigid or unplasticized form of PVC (uPVC) is extensively used in the building industry as a low maintenance material. For example, uPVC window frames and doors. The ‘u’ stands for unplasticized. You may also see it referred to as PVCu. The extra letter means fewer additives.
PVC can be made softer and more flexible with the addition of plasticisers, the most common are phthalates. In this form it is used in electrical wire cabling and vinyl flooring, for example.
How is PVC manufactured?
PVC is made from chlorine derived from salt water combined with ethylene (obtained from oil or natural gas) to form vinyl chloride monomer (VCM). This material is then mixed with other chemicals, such as phthalates, metal stabilisers, flame retardants and biocides to form the finished products.
PVC production has rightly come under the scrutiny of environmental and health bodies which have raised concerns over the level and types of emissions from factories. In the late 1970s vinyl chloride gas, used in the manufacture of PVC, was linked to cancers in workers in the BF Goodrich Plant near Louisville, Kentucky. Subsequent studies have shown repeated exposure may cause liver damage. The International Agency for Research on Cancer has concluded there is sufficient evidence in human studies that vinyl chloride gas can cause cancer.
Today production is highly regulated in Europe and enormous efforts have been made to ensure the plastics industry cleans up its act. According to the UK’s former Public Health England (now the UK Health Security Agency) while vinyl chloride is known to cause cancer in humans, the risk of exposure to the public is low.
Vinyl 2020 is a European PVC industry 10-year plan, a voluntary commitment to enhance sustainability of the product, invest in technology, minimise emissions and waste and boost recycling. Worryingly, production in China, the world’s biggest PVC producer, remains relatively unregulated.
What is the harm to human health?
Concerns continue to be raised about the potential harm to human health from the additives, particularly phthalates, used to make PVC more malleable. Researchers have linked individual phthalates with allergies in children, breast cancer and male infertility. In the US, the use of some phthalates in children’s products has been banned under the 2008 Consumer Safety bill. While in Europe the use of individual phthalates in toys and childcare items has been restricted as a precaution.
That’s not all, toxic heavy metals like lead have been added to PVC to improve stability. Lead has been shown to leach into drinking water from PVC pipes. In Europe the use of lead-based stabilizers is gradually being replaced.
Supporters of PVC argue the potential health risks have been hugely exaggerated. “Today after four decades of study and an equal number of years in which phthalates have been pervasive in the environment, no party has shown that phthalates used in today’s PVC, cause harm to humans when used as intended,” says John Wagner, green energy consultant in the article “7 myths about PVC – Debunked.”
Is PVC sustainable?
Critics say PVC can’t possibly be environmentally friendly. Almost all plastics are made from chemicals that include the production of planet-warming fuels (gas, oil and even coal). Our reliance on plastic prolongs our demand for these fossil fuels, says Greenpeace. Plastic also contributes to global warming.
Supporters of PVC argue the idea that alternatives are more sustainable or greener can be countered by looking at the embodied energy of these products. In his article, Wagner says chlorine can be “chemically unlocked” from salt through simple industrial processes. By contrast, copper, steel, aluminium and concrete “all require a great deal of energy to manufacture, which means they have a very high embodied energy. The mining and manufacturing process for each of these products are widely known for highly negative environmental impacts that far exceeds the low impact of the PVC manufacturing process.”
Disposal of PVC
Plastic doesn’t decompose like wood but sticks around for ages, threatening wildlife, says Greenpeace. Another issue is burning plastics in incinerators releases climate-warming gases and toxic air pollution from dioxins.
The destination for most redundant PVC in the UK is landfill. The concern is that additives, including plasticisers and metal-based stabilisers will leach from the PVC into the environment. Former Public Health England, now UK Health Security Agency, says leaching of chemicals can occur in landfill settings but in most cases is minimal.
Recycling PVC minimises its environmental impact and is supported by the plastics industry. Instead of going to landfill or incineration, waste PVC is returned to the manufacturers as raw materials for new products. Recycling is up from around 5,000 tonnes per year in 2000 to around 140,000 tonnes in 2019, about half of which is uPVC window frames. Less advanced is the recycling of plasticised PVC where additives can cause problems.
There can be few building materials that divide opinion quite as much as PVC. Ultimately, it’s down to the individual homeowner whether to use it or not. In a few areas, such as plastic wiring, it’s impossible to avoid. In other areas there are alternative materials available for pipes, window frames, doors and floors. PVC is often chosen as it’s cheap and requires little or no maintenance. Window frames can simply be wiped down if they get dirty and don’t require repainting. In some cases, it may not be so bad. For example, uPVC windows will last for 20-plus years and can be recycled. Most suppliers don’t make their own PVC. Instead, they buy it in, cut it to length and join the sections together to create windows, doors, guttering and trim. If you go down the plastic route, ask if the PVC was manufactured in Europe or China and then make up your mind.