Polyvinyl Chloride

PVC production started in India in the year 1961 when Calico Industries put up a plant based on Calcium Carbide route. In 1967 the first alcohol based plant was commissioned by Chemplast. The Company also pioneered the production of paste (emulsion) grade in the country. The first integrated PVC complex based on naphtha cracker was established in 1968 by NOCIL. In 1991 Reliance Industries Limited brought about a sea change in local production with a world scale plant (160 KT enhanced to 300 KT) based on imported feedstock. Today we have an installed capacity of 750 KT against a demand of 650 KT.

Market share of PVC among the thermoplastics in India is 23% growing at an annual growth rate of 6-7%. The major consumption sectors are Irrigation/water supply (38%), Buildings and Construction (23%), the remaining being used in medical, footwear, profiles, packaging etc.

In recent years, PVC – Vinyls have come under intense scrutiny on environmental grounds particularly the apprehensions regarding emission of Chlorine products and dioxins, and adverse aspects of Phthatates. This note provides authentic information disproving the widespread misgivings .

PVC has been under severe attack for almost 20-25 years when it was discovered in mid 70s that VCM monomer induces angiosarcoma, a liver cancer. Initially the problem was restricted to occupational exposure during manufacture. However concerns were expressed for risk to human beings. The PVC industry rose to the environmental challenge in a short time; first to reduce exposure of VCM during manufacture and then to contain it. The closed reactor technology coupled with clean reactor systems brought dramatic reduction in VCM exposure. Further the treatment of VCM by solvent absorption activated charcoal eliminated the emission to atmosphere. The occluded residual VCM in PVC particles was brought down from a level as high as 1000 ppm to the level of 1 ppm by slurry stripping techniques. PVC industry has passed the critical acid test. Today most of the PVC produced in the world contains very insignificant levels of residual VCM. Not surprisingly the Food and Drug regulatory bodies across the world do not consider the extremely low levels of VCM in food packaging a human health or environmental risk. It is even considered to be safe in its use in medical field.

Perhaps the biggest contemporary threat to PVC is the issue of its disposal particularly from municipal solid waste (MSW). The major volumes of PVC are used in products like Pipes, Profiles and Cables which have a long life-almost extending upto 50-100 years. PVC in packaging and disposable application (short life products) does not exceed 10-15% of the total consumption. Latest figures for 2000-01 show that “short life” PVC Products form only 8% of total PVC produced. Details are worked out in the following table. It is therefore not surprising to observe that PVC component in municipal waste is lowest (less than 0.5% by weight). PVC on account of its high chlorine content is considered by the environmentalist to be obnoxious. However the fact remains that its presence at such low levels in municipal waste streams could not cause any significant problems. It is argued that PVC (because of its chlorine) when burnt can form HCI and an organic chloride product called Dioxin (2, 3, 7, 8 – tetrachlorodibenzo-o-dioxin).

Figures in Thousand tonnes per year

In the above table:

* Figures in Bold indicate short term usage items, totaling up to    54000 tonnes per year.
* Only short-term usage items end up in the MSW

HCl is alleged by the environmentalists to be responsible for acid rain and Dioxin is considered to be toxic. PVC component in MSW is very low compared to other wastes fed to incinerators. A new study that analyzed 1700 test results from incinerators and similar combustor equipments at 155 facilities concluded that there is no relationship between the chlorine content of wastes and dioxin emissions from combustion process. It is the operating parameters of combustor which are critical factors in dioxin generation. The contribution to all the acid gases from the burning of PVC IS LESS THAN 0.25% and with the incinerators fitted with efficient gas scrubbers, this figure is lower.

Several research works carried out at reputed institutes indicate that atmospheric acidity caused by HCI from PVC is a very minor source (less than 0.25%). Most of the acid generated comes from automobile pollution (Nitrogen Oxide) and power plants (Sulphur Dioxide).

At present there is insufficient data to make a detailed assessment of the EDC/VCM/PVC industry’s role as a source of Dioxins. However current analysis indicates that the EDC/VCM/PVC industry is a minimal emission source. Waste combustion accounts for 95% of all known emissions with Municipal and Medical wastes incineration being the dominant source. A study has concluded that there is no relationship between the chlorine content of wastes and dioxin emission from combustor process. Dioxin formation takes place in the post combustion zone at a temperature zone around 400° C – 600° C by catalytic reaction with fly ash in the presence of hydrochloric acid. At temperatures above 850° C dioxins are destroyed. It is the operating parameters of combustor which are critical factors in dioxin generation. A survey of dioxin emissions in Netherlands, shows that contribution to dioxin levels from PVC is very small as compared to wastes from other sources. (Ref : Table )

Fires in offices which contain PVC have always given rise to controversy concerning dioxin emissions. Investigation of these fires with high PVC content indicate very little if any emitted dioxin in the immediate vicinity of the fire. This was shown at Miranda (Spain), where after a fire involving 15 tonnes of VCM/PVC, only .006 to .007 ug (ITEQ) per Kg of soil was found at around 100 meters from the factory while it was not possible to detect traces of dioxin in the water used to extinguish the fire at the analytical sensitivity of 0.14 ug (ppt). At Lengerich with 500 MT of PVC, authorities have published an official report which gave values of 0.1 to 5 ug/m2 at a distance of 100 metres, which are not considered dangerous. These values are comparable to those of stubble burning (1 ug per hectare) and wood fires (13 to 28 ug per tonne).
Dioxin formation in the fires involving copper cables with PVC insulation is expected to be 7.4 to 14 ug per tonne which is much less as compared to PVC-free cables insulated with paper, and with lead (21 ug/ton).

A two year study undertaken voluntarily by the Vinyl Institute in the U.S. shows that Vinyl is, at most, a negligible source of dioxin. Infact dioxin emission in 2000 has declined by 50 % since 1970, a period in which PVC production has more then tribled.

A review of the data generated in Europe shows the vinyl industry as a minor contributor to dioxin levels. Vinyl constitutes only 1% of the total chemical processes in general and hence represents only about one half of 1% of the dioxin source. The dioxin levels found in vinyl production are comparable to the amounts present in grass or soil and pose no threat to human health.

The vinyl industry’s voluntary dioxin characterization program for reassessment of dioxin levels further confirms vinyl’s minimal contribution to dioxin emissions. Sampling data from various points in the vinyl production process show emissions of about 24 gms. of dioxin to air, land or water or less than 1% of the 3000 gms that the EPA estimates are emitted annually by sources throughout the country. The recent dioxin source inventory shows the most dioxin coming from municipal waste incinerators, backyard trash burning, landfill and forest fires. [Vinyl and the Environment -Environmental Briefs – December 1999]

The US Environmental Protection Agency has always contained one mystery: the signal of the existence of a large “unknown” source of dioxin. One of these mystery resources is located to backyard trash burning. An increased amount of vinyl in the trash barrels did not produce high amounts of dioxin. Further, the design and the operating conditions of the incinerator and not the vinyl content of the waste are the determining factors in dioxin generation and emission. [Vinyl and the Environment – Environmental Briefs – July 1999]

Greenpeace and the other environmental groups accuse the chlorine industry to be the main source of dioxins in the environment. But, the whole chlorine industry and the PVC industry are only a minor source of dioxins today. The most important sources are the incinerators.

The amount of PVC or chlorine plays no important role in the amount of dioxins formed at incinerators. From more than seventy experiments at municipal incinerators, all over the world, there is evidence to prove that there is no relation between chlorine input and dioxin emissions.

On a production of 500,000 tonnes per year, about 4 gms of dioxin was formed. This is 500 times lower than the figures suggested by Greenpeace. After cleanup in a biological wastewater treatment and the incineration of the sludge of the waste treatment and the off-gases, about 40 milligram of dioxins are released to air and about 10 milligram are released to water per year. Thus, only 30 to 80 milligram of dioxins per year are released from a PVC factory producing hundred thousands tons of PVC. Nowadays, the dioxin levels are the same as much in 1945, even though the chlorine and PVC production is enormously higher than in those times.
Enclosed is an endorsement from ECVM removing some of the fears on dioxin coming from PVC.

PVC Polymer because of its chlorine content is inherently fire resistant. In fact among all the common polymers, PVC is the most resistant to fire. Not only it is better than the common plastics, it certainly shows some interesting advantages over conventional materials like wood. The self ignition as well as flash ignition temperatures of PVC Polymer as well as rigid PVC Products like window profiles having more than 80-85% content of PVC polymer are almost 150° C higher than wood clearly indicating that PVC would be more resistant than wood to initiate fire on its own or when heat is increased due to fire emanating from other sources. For spreading of fire, oxygen is essential – PVC polymer and Products used in infrastructure/buildings like pipes, conduits, profiles or even flooring and wires/cables have limiting Oxygen Index ranging from 30 to 50 compared to 21 present in normal atmospheric conditions or 21 limiting Oxygen Index of wood. It is therefore quite natural that all the building institutes around the world not only approve such PVC products for building/infrastructure but also provide it the highest ranking among the alternate materials that can be used for such applications.

In fact, rigid PVC products generally extinguish by themselves once the fire source is eliminated.

It requires high temperatures, continuity of fire and abundant supply of fresh oxygen to sustain fire in these PVC products.
PVC products tend to provide some benefits in fire situations. First of all burning of PVC tends to reduce or maintain heat instead of increasing it. Secondly, when PVC burns, it releases hydrogen chloride and relatively small amount of carbon monoxide.

Generally other materials on burning tend to produce carbon monoxide which is odorless but very toxic. Hydrochloric acid which has irritating smell warns the victims even when it is present in small quantity. Due to these two distinct benefits the fire authorities favour PVC products.

Experiments conducted by Boston Fire Dept. as well as Harvard University have shown that in a typical building fire HCI levels did not exceed more than 300 ppm. At such levels, there is no danger to human/animal fire victims.
Hydrogen Chloride being corrosive was thought to contribute to corrosion of concrete structure. However large scale experiments have proved that HCI emitted in fires from PVC products do not corrode such structures.

Phthalates are among the most studied materials in this world. Based on the best evidence to date, the producers of phthalates strongly believe that these products are safe and pose no risk to children or adults properly using products containing phthalate esters.

Phthalates are important since they make plastic flexible. These phthalates have undergone extensive health and safety testing. A phthalate commonly used in children’s toys is DINP. There is an extensive database that includes test results from studies that examined possible liver and kidney effects, cancer , reproduction and development as well as endocrine modulation. Based on the extensive date available, there is no scientifically validated evidence that shows that the use of phthalates in human toys poses a human health risk. The Phthalate Esters Panel stands by the extensive research and testing that shows that phthalates in toys are safe for intended use. The Consumer Products Safety commission has stated that the amount children may ingest does not reach to harmful levels. [Phthalate Esters Panel – November 2000]

DBP exposure in people was recently studied by the Centers for Disease Control and Prevention (CDC). Results were consistent with prior levels of exposure. The average DBP exposures were more than 60 times below the level mentioned by the US EPA.
There were earlier claims that the presence of plasticizers in vinyl flooring and wall covering could lead to childhood asthma. These claims have been discredited by the Institute of Medicine of the National Academies Of Science. The researchers have placed plasticizers in the study’s lowest category claiming that they could find only insufficient evidence. [Vinyl and the Environment – Environmental Briefs – May 2000].

In addition, phthalate esters have been shown to be readily biodegradable in tests conducted using a number of different protocols. In addition, the phthalate esters are easily photo degraded and biodegraded and hence they do not tend to persist in the environment.

A blue ribbon panel headed by Surgeon General C. Everett Kopp has declared that vinyl toys and medical products made with phthalate plasticizers are not harmful to children or adults. In fact, the panel has revealed that the use of phthalates in some medical devices makes them safer than alternative materials. Dr. Koop has reassured that the use of vinyl toys and medical products are safe. [Vinyl and the Environment – August 2000 briefs]

All aspects of the toxicology of phthalates are currently being assessed in a number of international forums, the most important of which are outlined below :

The Scientific Committee on Toxicity, Eco toxicity and the Environment (CSTEE) has issued opinions on the migration of phthalates from soft PVC toys and childcare articles in April and November 1999. In these opinions it has evaluated the extensive toxicity data available on the phthalates, identified No Observable Adverse Effect Levels (NOAEL) and, after applying a safety factor of 100, defined Tolerable Daily Intakes (TDI) for each of six phthalates. The TDI values have been coupled with a worst case exposure scenario to give guidance values for migration. If the guideline values are not exceeded then these phthalates can be used safely.

Thus all toxicological concerns have been taken into consideration by the CSTEE and they have concluded that the listed and assessed phthalates can be used safely in toys provided that the guideline values for migration are not exceeded.

United States Consumer Product Safety Commission (CPSC). The CPSC has evaluated the potential health risk to children under 3 years of age from teethers, rattles and toys made from PVC containing DINP. The evaluation included both in-vivo and in-vitro measurement of the migration of DINP during mouthing.
Based on this migration data and the ‘time of mouthing’ information obtained by the Dutch Consensus Group, the CPSC concluded that “few if any children are at risk from liver or other organ toxicity from the release of DINP from these products [The Use of Phthalate Plasticizers in Soft Toys-Environmental Briefs – April 2000]

Hypothesis on endocrine disruption and other health issues (ECVM report)
A number of scientific papers have given rise to concern about a possible general reduction in male sperm counts and other reproductive disorders. These have resulted in a hypothesis that certain products in the environment which mimic the natural female hormone oestrogen may be the cause. This has become known as the hormone – or endocirne – disruption theory. However, there is no study based on sound science that shows this actually occurs.
Extensive research is being carried out by the chemical industry and others in Europe, the United States and elsewhere, into endocrine disruption theory. Phthalates have been implicated as one of a number of possible hormone-mimicking chemicals but they are not the only substances under scrutiny along with many naturally occurring substances (phyto-oestrogens) found in plants and vegetables.

Concerns have been raised about a possible endocrine effect of some phthalates, although the most recent studies, which include in-vitro and in-vivo tests on DEHP have shown that there is no reason that the suspected phthalates would produce oestrogenic effects in humans.

It is, therefore, very unlikely that any significant risk to human reproductive health is associated with phthalate use. However, they continue to be rigorously researched and scientifically
assessed to confirm they are safe to use and pose no threat to health or the environment. Such assessments are currently being undertaken on five phthalates (DBP, DEHP, DINP and BBP) under the EU’s Risk Assessment Procedure (Council Regulation [EEP] 793/93).

While the International Agency for Research on Cancer (IARC), part of WHO, used to classify DEHP as “an agent possibly carcinogenic to humans”, this was based only on rodent studies and did not take into account more recent understanding of the underlying mechanisms. It has now changed its classification of DEHP to “not classifiable as a human carcinogen” based on existing scientific evidence that supports the safety of DEHP as a component of PVC medical products.

In addition the Specialized Experts Working Group of the European Commission has concluded that there is no evidence to warrant classification of DEHP as a carcinogen.
Recently three independent panels convened by Baxter Healthcare Corporation confirmed that DEHP does not pose a human cancer risk.

With regard to cancer, it is important to note that since 1980 a large number of investigations have shown that feeding high levels of phthalates to rodents over their lifetime causes a large increase in microbodies in the liver called peroxisomes. This ‘perixisome proliferation’ leads to the formation of liver tumors. However, when these chemicals are given to non-rodent species such as marmosets and monkeys (primates considered to be metabolically closer to humans), such liver peroxisome proliferation and liver damage is not seen. The changes seen in rats are therefore likely to be a species-specific effect.

The European plasticiser industry (represented by the European Council for Plasticisers and Intermediated – ECPI) is conscious of the genuine public concern which now exists around the use of phthalates and takes this very seriously. The industry is in favour of a public debate, and considers that it has a duty to respond to public concern by ensuring that there is an open exchange of information about the performance of its products. Clearly, if there were evidence that any single product presented a serious health risk, the plasticiser industry would have no hesitation in withdrawing it.

The industry is also committed to supporting and, where appropriate, commissioning further scientific research to make sure that the current use of phthalates poses no hazard to the health of people or the environment.

Vinyl is primarily derived from salt which is a virtually unlimited natural resource. The process of manufacturing vinyl has minimal releases to the environment. Because vinyl is so durable, its use on long – lived applications provides additional resources. When vinyl products do reach the end of their lives, they can be recycled into other useful products.

Even after a useful span of decades, vinyl products can be recycled into new applications lasting decades more. In the US, more than 3,500 communities accept vinyls in their recycling program. More than one billion pounds of vinyl were recycled from post-industrial and post-consumer sources in 1999, disclaiming the claims that vinyls cannot be recycled. Independent consulting firm Principal Partners have found that nearly all scrap is recycled back into the vinyl manufacturing process resulting in a notably high resource-efficient process. The plastics such as those used in milk jugs and soda bottles have higher recycling rates because of the presence of vinyl. The industry has helped develop the equipment that automatically separates vinyl from other post-consumer plastic packaging and expand recycling for non-packaging waste such as construction and demolition scrap. The use of incineration facilities together with the associated energy plays a complementary role to recycling and has allowed to reduce the volumes going into landfill.

Just one year after the Autovinyl recycling initiative began its activity of the recycling of automotive scrap, the coalition of the French Vinyl, automobile and equipment manufacturers was successful in its interim goal of recycling 5000 metric tons of vinyl the group reported that 1740 metric tonnes of automotive vinyl production scrap and vinyl products from end-of-life vehicles have already been processed by the recycling companies. Now, the company is focusing its initiatives to developing new products form these recycled material in the automotive industry and other sectors. By 2002, the coalition expects to be recovering 80 % of all vinyl automobile parts.

Ten vinyl manufacturers in Europe have teamed up to build a pilot plant to evaluate the technologies for vinyl recycling. The project is being funded by members of the European Council of Vinyl Manufacturers.

Solvay has recently announced a new technology called vinyl loop for recycling vinyl compound- based products. This process uses a solvent to separate vinyls from other materials such as polyester found in applications like architectural canvas and tarpaulins. The process is also found to be useful to recycle vinyl compounds from cables, pharmaceutical blister packs, floor coating and car dashboards. Meanwhile, Japan’s Toll Corp. announced recently a technology to recycle carpet panels and vinyl floor covering. The recovered wall covering is used to manufacture flooring and the carpet is recycled into new carpet material.

The amount of PVC in municipal (household waste is less than 1 %. Then PVC is combusted, it is converted into carbondioxide, water, hydrogen chloride and metal chlorides. However PVC provides considerably less Co2 for kg. of materials than the combustion of other materials such as oil, wood, and coal. PVC therefore makes smaller contribution in both green house effect. HCL is a hazardous acid gas which must be removed from the emissions of all municipal; and industrial waste materials.
Dioxins – which are generated as by products from industrial and combustion process – can also be produced in waste incinerator. However with advantage of modern incinerator technology, the control of all hazardous emissions in a matter of safe and effective operation of an incinerator.

There is some scientific evidence that PVC’s presence in municipal waste dream plays no special role in the amount of dioxin forced and released from incinerators.
Another comprehensive study by the Association of plastics manufacturers in Europe (APME) into combustion of mixed plastic waste and municipal solid waste of the Würzburg incineration plant in Germany demonstrated that increasing the overall contact of waste plastics is including PVC – did not produce any measurable increases in the production of dioxins and furans. All gaseous emissions recorded during the project completed at German emission standards.

The Global PVC production capacity in the year 2000 is 68 Bn Lbs ( 31 M MT) During the next five years ( i.e 2000 – 2005) , the world demand of PVC is expected to grow at an average growth rate of 4.7% This will take the Global per capita consumption of PVC to over 10 kg. Despite their maturity, substantial growth per capita remains in North America(> 40 kg) and Western Europe (> 30 kg).

The European Council of Vinyl Manufacturers (ECVM) represents the PVC producing industry, including the production of monomer, at European level. Its membership includes in companies representing 98 % of Western Europe’s PVC production. A major responsibility of ECVM is to monitor co-ordinate and promote programmes within the industry in order to assess the environmental impact of PVC on the environment, to develop the use of best environmental practices and to facilitate eco-efficient solutions for waste management and recovery.
In relation to the issue of dioxins we can make the following statements:

Manufacturing of PVC and of its monomer
1) Formation of very small quantities of dioxins only occurs in one of the process steps leading to the production of vinyl chloride, the monomer of PVC. These dioxin molecules are absorbed by the solid catalyst and hence are easily contained by filtration and destroyed by appropriate treatment of this catalyst.
2) Small quantities of dioxins could also be produced when incinerating chlorinated waste products, especially dioxin-containing heavy ends. However, this is the case for any incineration of chlorine containing organic material (also household waste) and is suppressed by adequate equipment and operating conditions.
3) The production of PVC itself and of PVC-based products takes place at temperatures far below those required for dioxin formation.
The PVC production chain is consequently only a very minor contributor to dioxins’ emissions throughout the world (much less than 1%) and this amount is regularly decreasing.

Incineration of PVC products

The European Union Commission published in July 2000 a Green Paper on the Environmental Issues of PVC. The Commission states that: “it has been suggested that the reduction of the chlorine content in the waste can contribute to the reduction of dioxin formation, even though the actual mechanism is not fully understood. The influence on the reduction is also expected to be a second or third order relationship. It is most likely that the main incineration parameters, such as the temperature and the oxygen concentration, have a major influence on the dioxin formation”. The Green Paper states further that “at the current levels of chlorine in municipal waste, there does not seem to be a direct quantitative relationship between chlorine content and dioxin formation”.

These views are based on more than ten in-depth studies carried out in various parts of the world.

In summary, one can be fully confident that dioxin formation in Municipal Solid Waste Incinerators is not related to the amount of PVC. Variations in combustion conditions are the most important parameter for the formation rates of dioxins in MSW incinerators. Removing PVC from Municipal Solid Waste would not reduce dioxin formation.
Yours faithfully,

A.Sevenster