In this section, information has been collected by PIPA New Zealand to provide factual answers to typical questions often asked on PVC and its health and environmental impacts. We have endeavoured to present research findings in a balanced manner and to update information as new scientific findings are published.
PIPA New Zealand invites dialogue on the information provided as part of its commitment which aims to meet community expectations for protection of people and the environment.
If you have any questions, wish to advise us of any errors or oversights, or wish to discuss any of the following matters, please contact PIPA NZ:
What is PVC?
Polyvinyl chloride or PVC and sometimes called Vinyl is the world's most versatile plastic , used to make everything from food wrap to auto body parts to water pipes. PVC is composed of two simple building blocks: 60% chlorine, based on common salt and 40% ethylene from crude oil
The resulting compound, ethylene dichloride, is converted at very high temperatures to vinyl chloride monomer (VCM) gas. Through the chemical reaction known as polymerization, VCM becomes a chemically stable powder, polyvinyl chloride resin.
PVC resin can be combined with a wide range of other materials such as plasticisers, stabilisers, lubricants and colorants to produce rigid (i.e. pipes) or flexible (i.e. raincoats) products. Not all PVC products use the same combination of materials
PVC is the second largest-selling plastic and the most versatile one and is used in hundreds of consumer and industrial products everywhere in the world.
Is Vinyl Chloride Monomer (VCM) hazardous?
Like many manufacturing processes, the production of PVC involves the use of materials that can be hazardous if improperly handled. The raw material vinyl chloride monomer (VCM) is the chief concern.
In the 1970s, the industry and scientists discovered a link between prolonged, high-level exposure to VCM among PVC production workers and a rare form of liver cancer called angiosarcoma. Radical changes to technology and processes were then rapidly introduced to protect the health of workers.
Today, the polyvinyl chloride production process is closed, with activities involving VCM taking place in sealed vessels. This minimises potential worker exposure, reduces environmental emissions and flammability risks. Exposure limits are now below one-thousandth of what they used to be, and no cases of the cancer have been detected in workers joining the industry since that time
The raw material polyvinyl chloride resin used in the production of PVC pipes is not manufactured in New Zealand but is all imported from Australia and Asia using certified manufacturing plants
No member of the general public is known to have suffered any harmful effect from VCM.
What are Dioxins?
'Dioxins' is a general term for polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). These are created in small amounts in a variety of synthetic and natural chemical processes. Agricultural burning off, incineration, forest fires, metal smelting, and certain industrial processes involving chlorine and other organic compounds all have the potential to create dioxins.
Dioxins are toxic and carcinogenic to some animals. The International Agency for Research on Cancer has classified the dioxin 2,3,7,8-TCDD as a known human carcinogen.
The level of dioxins in the global environment peaked in the late 1960s and early 1970s. Japanese Government data shows that daily human intake of dioxins fell by 75 per cent between 1977 and 19981. The US EPA has reported that dioxin emissions in the US fell by 80 per cent between 1987 and 19952.
The principal societal sources of dioxins in most western nations are municipal and medical waste incinerators3. It is widely believed that the primary means of further reducing the emission of dioxins is through the control of incinerator operating practices. This is less applicable in Australia, where most medical waste incinerators are relatively modern, and where there is only one, very modern municipal waste incinerator (Wollongong).
A 1998 report for Environment Australia estimates that 60-80% of dioxin emissions to air in Australia arise from agricultural burning off, residential wood combustion and bushfires. Waste incinerators and halogen chemical manufacture (including chlorine and PVC production), together contribute less than 1% to the total. This report is available on-line at
http://www.ea.gov.au/industry/chemicals/dioxins/pubs/dioxins.pdf.
Another Environment Australia review
(at http://www.ea.gov.au/industry/chemicals/dioxins/pubs/review.pdf)
includes the following comment on PVC:
"In general, the trend data (eg Alcock & Jones, 1996) support a conclusion that rates of dioxin emission and deposition are linked to a few specific chemical and industrial processes rather than to the additional production of chlorine and the increasing use of PVC."
Global levels of dioxins in the environment have been falling for 20 years. PVC resin production has trebled in the same period.
The Swedish EPA found that "a reduction in the PVC content of waste will not change the amount of dioxin emissions in flue gases, or significantly reduce the dioxin content in residual products from flue-gas treatment plants."5
A similar, broader finding was reached in a major study in 1995 by Rigo et al. In an analysis of data from 31 medical waste incinerators, he found "… there is no statistically significant relationship between the composition or amount of (dioxin/furan) concentrations in the gases emitted from the MWIs and the amount of chlorine in the waste feed."6
Rigo reached a similar conclusion on data from 63 municipal waste combustors
Do Polyvinyl Chloride resin factories emit large amounts of dioxin into the environment?
No. Studies in Australia, the US, UK and the Netherlands have shown that only very small amounts of dioxin can be attributed to VCM or PVC production. Dioxin emissions in Europe and the US have halved in the last thirty years while PVC production has increased 300%. In Australia, it is estimated that 60-80% of dioxin emissions to air arise from agricultural burning off, residential wood combustion and bushfires. The manufacture in Australia of all chemicals based on chlorine (i.e. halogen chemicals) contributes less than 1% to the total.
Are dioxins present in the PVC resin that is used to make everyday products?
No. Dioxins have not been found in PVC resin at the limits of detection, even using today's highly advanced measurement techniques. PVC resins or polymer are chemically stable, neutral and non toxic
The role of Chlorine in today’s World
Chlorine is an element with the chemical symbol Cl. It does not naturally exist in a pure state but can be manufactured from a number of sources, most commonly salt, or sodium chloride. There are many naturally occurring, widely abundant chlorine compounds. Chlorine's chemical nature is closely related to fluorine, bromine and iodine, a group of chemicals known as halogens.
Chlorine is a highly reactive substance with the ability to combine directly with other elements. This is one of the reasons it has become such an important chemical in today's society.
Chlorine is used in the manufacture of many of the products today's society depends on, including medicine, water purification, building products, paints, paper and plastics.
For more information on chlorine visit www.orica.com.au)
How much manufactured chlorine goes into the PVC industry?
Worldwide, about 35% of chlorine produced is used in the PVC industry. Chlorine is one of the most commonly occurring elements. Man-made chlorine is vital to many industries producing valuable modern products.
How does PVC Perform?
Because PVC resin can be combined with many additives and modifiers, PVC can meet the requirements for an exceedingly wide range of products in many industries.
PVC is often chosen over other materials because of its low cost, versatility and performance properties.
PVC is strong, durable, abrasion and moisture resistant; withstands rust and corrosion; is electrically non-conductive and has excellent fire performance properties.
PVC can be produced in almost any color, with end products ranging from opaque to crystal-clear.
Through a variety of processes, PVC can be modified to produce products as rigid as pipe or as flexible as upholstery and food wrap.
Because it contains less than half petroleum based material, PVC is the most energy-efficient plastic. And because it has been used for more than a half century, it is one of the world's most analysed and tested materials.
- A major basic component of PVC is salt an inexpensive renewable resource.
- PVC products consume less energy, generate fewer emissions and save more energy than many competitive products
- Most PVC products are durable and long-lived with pipes having a design life of 100years
What impact do PVC Additives have?
Additives typically constitute a small part of the overall PVC formulation and their use is closely regulated. All additives used in food and drug applications must have specific regulatory clearance
Plasticisers are used as softening agents and provide low temperature flexibility and weldability in flexible PVC products Phthalate ester plasticizers have been safely used for more than 50 years and are some of the most studied compounds in the United States from a health and environmental viewpoint. These plasticizers are used in wire and cable products, medical devices, toys, flooring, shower curtains and synthetic leathers such as automotive upholstery, as well as in pharmaceuticals and personal care products such as cosmetics and lotions.
There have been no confirmed reports of adverse health from phthalate exposure. A full report on the safety of phthalates was published by the American Council on Science and Health and is available on http://search.medscape.com/px/mscpsearch?QueryText=phthalate+safety&searchfor=Clinical&cid=med
Plasticisers are not used in the manufacture of rigid PVC pipes
Stabilisers: Many polymers, including PVC, require additives during the manufacturing process. Individual additives include heat and light stabilizers, colorants, impact modifiers, processing aids.
These include the metals tin, barium, zinc, calcium and, decreasingly, lead and cadmium. Most stabilisers are used in rigid PVC applications such as pipe and other construction products thanks to their processability and durability.
Lead-based stabilizers are used principally in PVC wire and cable insulation. No lead is used in PVC potable water pipes manufactured in New Zealand and nearly all other PVC rigid pipe products produced here are lead free now with total lead phase out planned for the end of 2006. .
Because the additives are firmly bound within a rigid PVC matrix, there is no mechanism by which these additives can escape into the environment at levels that pose a health risk to humans. The CSIRO (REFERENCE SITE) found that under normal use conditions of PVC pipe; its contribution to levels of lead in the environment is small relative to contributions from other sources.
New studies affirm that disposal of metal-stabilised PVC waste in landfills poses no appreciable risk to human health or the environment. In fact, PVC sheet is used as landfill liner to help prevent leachate from contaminating groundwater, specifically because PVC is so resistant to the aggressive conditions typically found there.
In short, the demonstrated performance and scientific facts about stabilizers confirm that they are the right choice for most rigid PVC processing. Extensive testing and review have shown that there is no risk to processors, consumers or the environment when these stabilisers are used as intended
What happens when PVC products burn?
PVC has low flammability and rate of heat release due to its low organic/high chlorine content. Pure PVC will self-extinguish once the external heat or flame source is removed. Rigid PVC materials such as those used for pipe, vertical blinds and siding, are recognised for their excellent fire retardant properties. The fire properties of flexible PVC products depend on the quantity and composition of plasticiser added
Is PVC a danger to people when a building catches fire?
The toxicity of building fire emissions from PVC is neither better nor worse than for many other common materials. The most important products in any fire are heat, smoke and carbon monoxide. These are produced by all organic materials when they burn. Hydrogen chloride is produced when chlorine-containing materials, including PVC are burnt. It is a common irritant gas, and has a very pungent odour so is quickly detected as opposed to carbon monoxide. At the levels encountered in building fires, hydrogen chloride remains an irritant and is not lethal. To our knowledge, no building fire fatality has ever been attributed to PVC by building fire authorities.
Does the incineration of PVC cause the emission of large amounts of dioxins?
It has been demonstrated that PVC in the waste stream of properly operated incinerators has a negligible effect on the amount of dioxins emitted. Dioxin emissions are primarily the result of combustion temperature and efficiency of operation, both of which can be controlled with the use of modern incineration technology. In Australia, it is estimated that agricultural burning off, bush fires, cement production and residential wood combustion are among the most significant contributors to dioxin emissions to air. Municipal waste incineration and halogen chemical manufacture contribute less than 1% to the total.
Can rigid PVC pipes be recycled?
PVC being thermoplastic material means that pipes can readily be recycled and reused in useful alternative products. Worldwide there are many PVC recycling schemes in place
Pre consumer PVC pipe waste is easy to separate as part of the production process. This results in high quality recyclate material and a high recycling ratio. Currently New Zealand pipe manufacturers recycle almost 100% of pre consumer waste PVC.
Post consumer waste recycling s more difficult to achieve because of:
- The degree of contamination with other materials
- Differences in the composition or specification of the PVC waste
- A regular supply of consistent quality waste
Consequently the level of PVC pipe post consumer recycling in New Zealand is low
Although recycling of plastics generally has gathered momentum over the last ten years it is only recently that building products such as pipes have been identified as potential recycling materials. PVC pipes form high quality recyclate waste but in low quantities as there is a considerable time lag between PVC consumption and PVC waste creation (Long useful service life for pipes). Also much of this pipe will remain buried after its operational life is over. That leaves pipe off cuts and demolition materials as other sources of scrap excluding imported material.
In New Zealand PVC pipes have been in use for the last 35 years and have an expected lifespan of 100 years or more. Meanwhile PIPA New Zealand is putting pilot schemes in place to look at increasing the level of post consumer recycling of PVC pipe as part of an ongoing commitment to a sustainable environment
Does PVC pollute soil and groundwater when disposed of in landfills?
Studies have been done to test whether PVC pollutes groundwater and soil in landfill. Such studies show that PVC does not degrade in landfill and is not expected to add to the toxicity of leachate. Minute quantities of metal stabilisers may leach from PVC but the quantities are considered an insignificant contribution to heavy metal concentrations in landfill. Although vinyl chloride gas may be present in landfill, it is formed from the degradation of chlorinated hydrocarbons not from PVC, which does not degrade.
