More Than 30 Years of PVC Recycling—Need for Regulation (2024)

1. Introduction

As documented in our “Critical Inventory” [1], the PVC industry’s track record to date of increasing the sustainability of PVC plastic is not convincing, although the industry takes a different view [2]. The question, therefore, arises as to whether legislators should intervene in Europe or at national levels.

Regulatory action must be well justified in each case. PVC differs from all other plastics, as described in our “Critical Inventory” [1], due to the high chlorine content in the polymer and the share and characteristics of additives. Various studies and reports have been submitted by the EU Commission in order to prepare for possible regulatory action, particularly with regard to environmental and health questions [3]. The adoption of the EU’s Green Paper of 2000 was “an important milestone in the development of a global Community strategy on PVC. The Green Paper tackles two main issues:

Environmental and health questions concerning the use of certain additives in PVC (particularly lead, cadmium and phthalates);
The question of waste management (landfill, incineration, recycling of PVC waste): PVC waste is expected to increase by about 80% over the next twenty years” [4].

Many of the problems mentioned in 2000 are still pressing today. So, in 2022, the EU Commission presented a further report entitled: “The use of PVC (poly vinyl chloride) in the context of a non-toxic environment” [4]. ECHA’s recently presented “Investigation Report” [5] is of particular importance, as it contains a range of proposals for the further regulation of PVC.

Regulatory areas of action must be considered throughout the entire life cycle of the plastic. This paper is organized along the entire life-cycle of PVC: Section 2 deals with the production, Section 3 with the consumption, and Section 4 with the end-of-life phase (post-consumption). These three phases are taken up again in the conclusion in Section 5 in the order of their relevance to the need for regulation.

2. Production Phase

Official data on the production of PVC or PVC compounds in Europe are not available; there is only data on consumption (see Section 3). The manufacturing of the monomer VC, the polymer and some additives is subject to the regulations of the chemical industry in Europe.

For the marketing of the polymer or compounds, justifications for government intervention only arise from the downstream life cycle phases, which we will discuss below. ECHA takes a rather critical view of a phase-out because, following their knowledge, the production of PVC is safe, and on the other hand, PVC is a low-cost plastic, and other plastics [6], such as non-plastic alternatives, are only available as substitutes at higher prices. This chapter will, therefore, first examine how PVC is priced and how the markets are strategically linked.

2.1. Soda

To understand the economics of PVC, we need to look back a little further into the last century. Sodium carbonate (Na₂CO₃, “soda”, “soda ash” or “washing soda”) was an important substance for carrying out chemical reactions. Due to its alkaline properties, soda was used for many purposes (paper industry, food production, chemical industry). Soda ash is found in natural minerals (such as salt lakes) and can be obtained from certain incinerator ashes or by chemical conversion of sodium chloride. Over 100 years ago, it was discovered that soda could be made even more reactive (corrosive) through chemical conversion, for example, through the so-called soda lime process, using naturally occurring calcium carbonate (limestone) and sodium carbonate (e.g., natron from soda lakes). This is why sodium hydroxide (NaOH) is, to this day, still called ‘caustic soda’ in English. Caustic soda was able to open up even more areas of application than (simple) soda, such as dissolving metals from ores. As a result, soda and caustic soda were, and still are, outstanding bulk chemicals for industry.

In addition to the chemical extraction of caustic soda, an electrolytic process was added at the end of the 19th century that could also produce caustic soda from salt: chlor-alkali electrolysis. The chemical and electrolytic processes for the production of caustic soda were in competition with each other. A CIA report from the 1950s on the situation in the USSR and the USA shows the strategic importance of alkali extraction and the competition between the processes [6]. In the following years, the electrolytic production of caustic soda gradually became more economically viable than chemical production (today, 65% of the global market). However, chemical production is maintained in a medium-sized form, particularly in emerging markets.

2.2. Chlorine

Chlor-alkali electrolysis is—as already stated—an industrial process for producing caustic soda (sodium hydroxide, NaOH), chlorine (Cl₂) and hydrogen (H₂) from common salt (NaCl) and water. As a co-production process, it produces stoichiometrically equal amounts of these products: 2 NaCl + 2 H₂O → H₂ + Cl₂ + 2 NaOH. In terms of mass, 1120 kg NaOH (i.e., 2240 kg NaOH (50%)) and 28 kg hydrogen are produced per 1000 kg chlorine [7]. To date, just under 70 chlor-alkali electrolysis plants are in operation in Europe, with a production capacity of a good 11.6 million tonnes of chlorine per year [8]. With 15 chlor-alkali electrolysis plants and a production capacity of 5.1 million tonnes, Germany is the largest chlorine producer in Europe. “At the beginning of the 1990s, there was a clear surplus of around 20% of caustic soda, so that chlorine (production in Germany in 1997: 3.5 million tonnes) can be regarded as the volume-determining product of this process” [9] (p. 42).

But in the beginning, the market for caustic soda (NaOH) was the driving force behind the success of chlor-alkali electrolysis. For the abundant chlorine, a market had to be found. Initially, the focus was on inorganic chemicals (chlorides). At the end of the 19th century, chlorine was introduced for drinking water disinfection (Hamburg, 1893) and later as a bleaching agent in the pulp and paper industry. During the First World War, some of the chlorine was used on the German side for chemical warfare. Later, organic substances were added. In 1935, the mass production of PVC began at the Wolfen and Bitterfeld plants of IG Farben AG, and PVC became the most important sales market for chlorine. IG Farben was formed in 1925 from the merger of eight German companies—Agfa, BASF, Bayer, Cassella, Chemische Fabrik Griesheim-Elektron, Chemische Fabrik vorm, Weiler-ter Meer, Hoechst and Chemische Fabrik Kalle.

Globally, 35 to 40% of the chlorine from electrolysis is currently used for PVC production [10]; in Europe, the latest figure was 31% [8]. With PVC, chlorine becomes a component of the manufactured product. Chlorine is also used as an agent to produce reactive intermediates such as propylene chlorohydrin, phosgene or epichlorohydrin. These intermediates are then used in further reactions to produce other plastics, among other things. The largest share goes via phosgene to produce isocyanates as monomers of polyurethanes. In all these plastics, chlorine does not appear in the product but leaves the industrial plant as chloride via wastewater or is utilized as hydrochloric acid (HCl). HCl is then used for food processing, steel processing, removing sulfur from petrol, hydraulic fracturing and the production of latex and metal chlorides (e.g., for fireworks) [11].

Today, the demand for caustic soda in Europe is largely taken up by the chemical industry, pulp and paper industry, food industry and alumina and other metals industry. For hydrogen, there are various areas of application, like steam generation, in the chemical industry [8] and—prospectively—in the field of energy storage [12].

2.3. The Economy of PVC Production

As the price of chlorine (and, therefore, of PVC) could be kept low through co-production, the industry was able to establish PVC as a mass plastic for the construction sector.

Since—as explained in more detail in our “Critical Inventory” [1]—PVC can only be made usable by first adding stabilizers, the construction sector with its broad range of uses is the ideal area of application. Stabilization only had to be “extended”.

There is really nothing reprehensible about the strategy of looking for a new use for a waste product from a chemical process—on the contrary. This happens in countless processes in the chemical industry. Entire sites, such as the one of BASF in Ludwigshafen, live this interconnected concept. However, this mainly involves organic substances consisting of carbon, hydrogen and oxygen. PVC is a special case here because chlorine is not otherwise bound into a chemical product to any relevant extent.

As chlorine as a gas or liquid is extremely dangerous (see above: war gas) and can, therefore, only be stored in small amounts to a great expense, the local and timely use of chlorine is a key prerequisite for economic success. Although chlor-alkali electrolysis is financed economically via hydrogen and sodium hydroxide, it is still controlled by chlorine sales. If sales of chlorine, i.e., PVC, stagnate, technical and economic constraints arise. In this case, chlorine could theoretically be disposed of by converting it to chloride. However, this could not be compensated for economically because the price of electrolytic caustic soda is “capped” [13]. As, on the one hand, some consumers of electrolytic caustic soda, who can live with a weaker alkali if the price goes too high, can switch to soda (sodium carbonate, Na₂CO₃) (substitution) or, if, on the other hand, the price remains high, the market could ramp up or reactivate the remaining capacities for the chemical production of caustic soda [13]. Essentially, that means if the price of PVC is too high, this can lead to a slump in sales of the plastic. If this process continues for longer, capacities in the chlor-alkali industry would have to be reduced. This would, in turn, increase the market opportunities for the chemical production of caustic soda—a development that would be undesirable for all players in the PVC production chain—and would certainly lead to strategic prices in order to avoid this development. This makes it clear why parts of the chemical industry are fighting so doggedly for this plastic.

All market players are aware that the intricate construct of chlor-alkali electrolysis only works if PVC can be offered at a significantly lower price than polyethylene (PE), for example. As the raw material for all competing plastics is the same—naphtha or the high-value chemicals from the hydrocracker—the price of chlorine is the decisive factor. This becomes even clearer when comparing PE and PVC from the production side. In each case, the raw material is ethylene from the cracking process, i.e., the same starting material. And the conversion process to the respective polymer is technically more complex for PVC than for PE. On the other hand, the manufacture of PE requires high-pressure equipment. So, in the end, only the price of chlorine makes PVC more attractive than, for example, PE.

Let us summarize: Due to the limited storage capacities for chlorine, chlor-alkali electrolysis is generally controlled by chlorine sales: “Since chlorine cannot be stored, chlor-alkali plants are operated in line with demand for chlorine, itself highly influenced by the demand for PVC” [10]. If the PVC market falters, the electrolysis plants are scaled back. This also leads to a loss of revenue for the other linked products (electrolytic caustic soda, hydrogen), which exacerbates the economic problem. PVC sales, which account for around 35 to 40% of chlorine globally [10], are therefore vital for the chlor-alkali industry. The price of PVC is kept strategically low via the price of chlorine, which is possible due to joint production. This explains the economic success of PVC in the production phase. Below we will examine the costs and challenges that PVC poses for the end-of-life phase. ‘Vinyl’ disagreed with our analysis: “As for any commodity, the market price of PVC is driven by demand and supply conditions. There is no external force maintaining the price ‘strategically’ low” [2].

3. Consumption Phase

The sales volume of uncompounded PVC in the EU amounted to 5.2 million tonnes in 2021 (Eurostat, 2023b, cited in [14]), which (according to the European Chemicals Agency ECHA) corresponds to around 6.8 million tonnes of PVC compounds. Adjusted for the import (0.5 million tonnes) and export quantities (1.2 million tonnes), 4.5 million tonnes of unmixed PVC polymers were, therefore, used in Europe, corresponding to 5.9 million tonnes of PVC compounds [1]. Almost 70% of this was used in the construction sector, mainly for pipes, floor coverings, cables and window/door frames [5].

As pure PVC is hard, becomes brittle at low temperatures, and begins to decompose at temperatures above 160 °C, which impairs processability (extrusion or injection moulding), various additives are added to the polymer to eliminate these weaknesses, such as plasticizers, stabilizers and other additives [1]. The authors of a study commissioned by the EU Commission identified various risks, particularly in relation to the additives used in PVC compounds [5]. However, they considered the data gaps to be so large that there were no recommendations for action. In particular, the question of the extent to which the additives—especially plasticizers—can leak out from the plastic seemed unclear, at least on the basis of the publicly available data. ‘Vinyl’ stated to us: “Many reports of studies on the topic of migration have been published that make clear which are the migrating concentrations and their associated risks” [2].

The risks of the consumption phase have been known for decades: as early as the 1990s, for example, DEHP levels in Japanese homes were found to be, on average, 10 times higher than in outdoor air. And measurements in 2000/2001 in about 130 apartments and kindergartens in Germany showed a median DEHP level in house dust of just around 1 g/kg (median: 703 mg/kg; range: 31–1763 mg/kg) [15]. These old studies can be “stacked” further [16]: “Children come into contact with DEHP released from a variety of products, including building materials, and flooring and wall coverings. In 2004, researchers in Sweden found that DEHP (and butyl benzyl phthalate) concentrations in dust were associated with PVC flooring and wall materials in their study of 390 homes [17]. In 2014, French researchers evaluated indoor air and dust in 30 French homes; again, phthalates, including DEHP, had the highest concentrations in both air and dust [18]”.

It was, therefore, consequent to clarify the need for the regulation of PVC and PVC additives in more detail. To this end, the EU Commission commissioned the European Chemicals Agency (ECHA) to draw up an “Investigation Report”. The report has been available since the end of 2023 [5]. In it, the ECHA sees a need for the following actions: “Regulatory action is needed to minimize risks from plasticizers and, in particular, ortho-phthalates” that have structures that have already shown reproductive toxicity or endocrine effects for related substances.

“Regulatory action is needed to reduce the risks from the organotin substances”.
“Regulatory action is necessary to ensure minimization of the releases of PVC microparticles and prioritized PVC additives”.
ECHA also sees risks for flame retardants and points out that a broader view is required here [19,20], which also includes other plastics.

The substance-related need for action is based on the possible migration or emissions from plastics. The risks are seen both for the environment and for humans. The need for action can be handled via the respective REACH procedures. It is now up to the EU Commission to trigger mandates. The regulatory consequences for reducing emissions of PVC microplastics are more difficult. The focus here is particularly on the recycling industry, as high emissions are assumed during processing (e.g., shredding). For example, a measurement campaign at a recycling plant for mixed plastic waste in the UK showed that around 6% of the plastic waste (4–130 kg/t) was discharged as microplastics with the wastewater [21]. The plant had a high separation efficiency for particles with a size above 40 micrometres (μm), with the majority of particles with a size of 5–40 μm being separated. Particles with a size < 5 μm were generally not removed by the filtration and ended up in the wastewater. From their data, the authors concluded that without wastewater filtration, 13% of the plastic throughput would end up in the wastewater. The authors of the study from the UK cite two comparable publications, one on PET bottles [22] and one on different types of plastic waste (electronic plastic waste, PET bottle waste, and household plastic waste) [23], and conclude that—taking into account the different analytical methods used to determine the concentrations of microparticles in the process and wastewater of the recycling plants—the results of all three available studies are coherent [21]. However, the database for this is very small so far. This will certainly need to be investigated further in the near future. ‘Vinyl’ pointed out that the mentioned studies did not process pure PVC waste [2]. This is correct, but also not ECHA’s and our point: treatment like shredding and washing will produce the problem for all plastics, including PVC.

The risks of microplastic emissions, for example, for the marine environment, have been scientifically described. PVC microplastic emissions are considered by the ECHA to pose an outstanding risk because PVC contains the highest quantities of problematic additives of all plastics. ‘Vinyl’ contradicted ECHA’s referring evaluation with the argument that “all other plastics contain additives … that can easily leach out from microplastics” [2].

There are many areas of action for the risk management of microplastic emissions, and these include, in particular, European industrial installations legislation (Industrial Emissions Directive (IED), Best Available Technique (BAT), BAT Reference documents (BREFs)), where limits could be placed on emissions via the air or water pathways.

Proposals for phasing out PVC itself are considered by ECHA to be socio-economically difficult, partly because PVC as a plastic is generally cheaper (PVC is, therefore, the cheapest option). A complete ban would, therefore, have economic disadvantages. ECHA recommends further assessments for a sectoral phase-out of PVC: “When considering which PVC uses contribute most to the environmental risks identified for the priority additives, cable (a soft PVC use) stands out as the only contributor to the releases of priority additives. …The substitution of PVC with alternative materials in cables would be less costly than for other uses, and therefore a restriction of PVC in cables to minimize the risks of additives seems worth further evaluation” [5].

4. End-of-Life Phase

PVC leads to problems as soon as PVC products become waste. Leaving aside the legacy additives (see [1,24] and Section 4.3), most of the problems are related to the chlorine in the polymer molecule.

4.1. PVC Stock

As calculated in our “Critical Inventory” [1], around 6 million tons of PVC (compounds) are currently used in the EU every year. In the 1990s, the figure was already 5 million tons [25]. At that time, around 85% of this ended up in the construction sector. Products such as pipes, sheets, cables, hoses and profiles have a service life of at least 30 to 50 years or more. This creates a gigantic stockpile, deposited in our buildings, etc. By 2010, this stockpile had increased to a total of 270 kg/capita [25]. There are no current figures for today’s situation. Since the 1990s, the PVC stockpile has grown by around 7 kg/capita per year. With this growth, the current figure would be just under 370 kg/capita, which would correspond to an in-use stock of around 160 million tonnes of PVC (compounds).

The problem of accumulated PVC stocks in our technical environment is not a new finding; it has been recognized since the 1990s (see Figure 1 and German Umweltbundesamt (ref. [9], p. 36), but this development has not been stopped.

Figure 1 shows an estimate for Germany (created at the end of the 1990s [26,27]) as to when the PVC waste plastics were put into circulation. The different options for the development of the PVC waste were considered in two scenarios. Scenario A assumes a (conservatively) estimated growth rate in new PVC production of 2% per year (per annum, p.a.) from 1998, plus 1% p.a. from 2010 and plus 0.1% p.a. from 2040. Even though government intervention was not apparent at that time, a phase-out or better conversion scenario was nevertheless presented in scenario B, in which PVC production fell by 6% each year—in relation to 1997 production. According to scenario A, the volume of PVC waste in Germany (excluding packaging) at the beginning of the 2020s was expected to be around 920.000 tonnes. This forecast is quite close to the data now reported by ‘Vinyl’ [28]: “Compared to 2017, the volume of PVC waste increased by almost 24 percent to 861,000 tonnes in 2021. This increase is determined in particular by the increasing return of durable building products, which have been increasingly installed since the 1960s, 1970s and 1980s”. According to [25], the amount of PVC waste has increased from around 3 kg per capita per year in the 1990s to just under 5 kg in 2010. Extrapolated to today, we are probably looking at a good 6 kg per capita per year. This is in line with forecasts made by experts in 1990. Assuming that the use of PVC in the construction industry would remain more or less constant, they calculated that from around 2000/2005, around 0.5 million tonnes of PVC residues (equivalent to a good 6 kg/capita) would have to be disposed of from construction waste every year [7].

In summary, it can be said that solving the stockpiling problem is a matter of urgency, not least because the quantities stockpiled are increasing every year. As shown above, the annual volume of PVC waste is increasing, which the waste management industry has to cope with. Assuming that PVC consumption remains more or less unchanged but the stock is increasingly transferred to the waste management sector, the growth of the stock slows down. However, according to our estimates, there is still a slight increase in the in-use stock. As the service life of PVC products and buildings is getting on in years, an avalanche of PVC into the waste management sector is to be expected in the coming years. What options does the waste management industry have to absorb this development? We will discuss this in the following.

4.2. Setting up a Chlorine Cycle to Cope with the PVC Stock

Do we need to set up a chlorine cycle to solve the todays and especially the future stock-problem? In Germany, this discussion was held decades ago. Here is a quote from the Enquête Commission of the German Bundestag [29] on the subject: AgPU (Arbeitsgemeinschaft PVC und Umwelt, German Working Group on PVC and Environment) “expects that in future a capacity of 240,000 tons of PVC mono-incineration plants will be required annually, in which 144,000 tons of HCl will be produced. The increased supply of HCl will lead to a corresponding reduction in electrolysis capacity. … Assuming a collection rate of 80%, 360,000 tons of HCl would be produced from 600,000 tons of PVC waste.” (Seitens der AgPU “wird damit gerechnet, dass zukünftig eine Kapazität an Monoverbrennungsanlagen von 240.000 t PVC jährlich benötigt wird, in denen 144.000 t HCl anfallen. Das erhöhte Angebot an HCl führt zu einer entsprechenden Rückführung der Elektrolysekapazität. … Eine Erfassungsquote von 80% vorausgesetzt, würden aus 600.000 t PVC-Abfällen 360.000 t HCl entstehen”.)

The PVC industry and AgPU, as mentioned, already advocated closing the chlorine cycle in the 1990s. PVC mono-combustion was the main option promoted by the industry for years. The produced HCl could be made available to the chemical industry for oxychlorination for VC production, for example. However, a relevant closure of the chlorine cycle leads to an excess of HCl [29], which results in a chlorine surplus that industry has to manage.

A relevant chlorine surplus, regardless of the cause, can only be absorbed by closing down electrolysis plants. This would require, as we have analysed above, expensive imports of caustic soda or result in increasing the more expensive chemical causticizing processes [13].

The costs of establishing a chlorine cycle are difficult to estimate. “Initial estimates of the costs for the processes described indicate that they could be in the range of 100 to 400 euros/ton of waste delivered, with the REDOP process (authors’ note: reduction of iron ore by plastics in blast furnace plants) tending to be at the lower end and the DOW/BSL (authors’ note: rotary kiln process) process at the upper end” [30]. ‘Vinyl’ has now informed us that these processes are no longer “relevant” and that they have been abandoned for technical and economic reasons [2].

4.3. Material Recycling of PVC to Cope with the Stock

Mixed PVC waste cannot be processed into high-quality products due to the different plasticizer types and concentrations (melting point, product hom*ogeneity [31]). And even in the case of separately collected construction products, material recycling is complicated.

The propagated material recycling (post-consumer waste, see our “Critical Inventory” [1]) has been stagnating for years at a low level. In our opinion, this is not an inability on the part of recyclers but has to do with the chemical composition of PVC. ‘Vinyl’ gave another explanation for the stagnation: “… mainly due to lack of clean and pure waste streams and inherently variable composition of waste, which creates major technical hurdles” [2].

Given the disappointing recycling rates, the question arises as to whether technical progress (e.g., swelling coupled with ball milling [32] or solvothermal treatment [33]) can improve mechanical or physical recycling results. The PVC industry sees opportunities here to increase “high quality recycling” [2]. But the key will certainly lie in improving sorting techniques. This will require investment, which, in ‘Vinyl’s’ opinion, fails due to “recurring legal uncertainty on how the circularity will be developed in Europe” [2].

And the additives also produce legal problems, which are not solved to this day. Many of the additives that were once commonly used are now banned or strictly regulated—the so-called “legacy additives” [1]. And this list is to be updated. In November 2022, ECHA published a prioritisation list of additional 63 suspected substances containing heat stabilisers, plasticisers and flame retardants [34,35].

The content of additives also determines whether the PVC waste must be classified as non-hazardous or hazardous waste. E.g., the amendment to Annex VIII of the Basel Convention inserted a new entry, A3210, which clarifies the scope of plastic wastes presumed to be hazardous and, therefore, subject to the PIC procedure. The new entry became effective as of 1 January 2021 [36]. The classification AC300 (notification required for shipments within the EU or between OECD countries) resp. A3210 (hazardous plastic waste imported from non-OECD countries; waste with code A3210 may not be exported to non-OECD countries); this applies—under others—to soft PVC waste containing hazardous stabilizers or phthalates in concentrations such that a hazard-relevant property (e.g., DEHP over 0.3%—HP10 toxic to reproduction), such as PVC flooring waste or cable peeling residues from old cables [37,38].

In summary, it can be said that material recycling cannot make a relevant contribution to solving the stock problem, on the one hand, because today only 12% is recycled at all, and on the other hand, because it is questionable whether there is a sense and a need for billions of additional low-quality recycling products of around more than 100 million tonnes for the EU. Rather, they represent a new stock problem, with even greater difficulties of recycling at the end of their service life.

4.4. Chemical Recycling of PVC to Cope with the Stock

Chemical recycling technologies such as pyrolysis, gasification, hydro-cracking or depolymerization are suitable for recycling mixed plastic wastes [39]. But “currently available methods are incompatible with chlorine-contaminated feedstocks” [40]. As PVC interferes with the recycling of other polymers, the input of PVC is limited (pyrolysis) or even not accepted (hydrothermal liquefaction, supercritical) ([39], supporting information).

The current and previous scientific literature is full of suggestions as to how to recycle plastic waste containing PVC compounds or mono-fractions of PVC (compounds) chemically. However, a two-stage approach is regularly required here. After pre-treatment to remove the chlorine, the full range of chemical recycling is seen as a possible second step [39,40,41,42]. But, to date, not a single large-scale plant exists that can chemically recycle relevant quantities of PVC waste [1]. One of the reasons why this has not been done voluntarily by the industry to date is the economy of chlor-alkali electrolysis, too. Industrial-scale chlorine or chemical recycling plants are likely to be larger than 100,000 t/a if they are to be operated economically. One likely consequence: chloro-alkali electrolysis capacities would have to be reduced, resulting in plant closures and economic losses [29].

4.5. Co-Incineration of PVC in Industrial Plants to Cope with the Stock

Chlorine interferes with energy recovery in cement plants [43]. Taking account of their local raw material situation, many cement plants (in Germany) have already operated bypass systems in order to control the chlorine and alkali balance of their kiln systems [44]. The use of refuse-derived fuels (RDF) has a significant impact on internal material cycles. In 2022, e.g., the German and Austrian cement industries used more than 70% refuse-derived fuels for their thermal energy needs, mainly mixed fractions of industrial, commercial and municipal solid waste, waste plastics, sewage sludge and waste tyres [45]. If RDF have a higher chlorine content than standard fuels, it is necessary to set up a new or to increase an existing bypass in cement plants that have not previously been affected in order to prevent the build-up of a chlorine cycle and the resulting caking. In this case, the energy balance of the process is also affected. For example, the removal of hot raw material and hot gas leads to a higher specific energy consumption of about 6 to 12 MJ/t clinker per percentage point of removed kiln inlet gas [46].

This problem can be solved by limiting the chlorine content in the input [43]. Across Europe, there are quality standards for RDF that categorize them into classes focusing on the key properties, namely net calorific value (NCV), the content of chlorine (Cl) and mercury (Hg), that are defined by boundary values (e.g., arithmetic mean, median or 80th percentile) [47]. For chlorine, the classes (% in mass (d)) are class 1: ≤0.2; class 2: ≤0.6; class 3: ≤1.0; class 4: ≤1.5; class 5: ≤3). According to general operating experience, the chlorine content should be below 1% by mass (dry), as chlorine causes problems for many RDF processors. This is already a major challenge for RDF processing today.

Overall, waste co-incineration cannot increase the input of PVC (rather the opposite) and, therefore, in the future, cannot provide a relevant contribution to solving the stock issue.

4.6. Combustion of PVC in Municipal Solid Waste Incineration (MSWI) Plants to Cope with the Stock

Today, the main route for PVC waste is municipal solid waste (MSW) incineration (see our “Critical Inventory” [1]). Within waste incineration, chlorine is converted to hydrogen chloride. HCl has a corrosive effect and increases the costs of flue gas cleaning. In the past, around 50% of the chlorine input in incineration plants has been attributable to PVC [3]. It is assumed that due to the decline of PVC in the packaging sector and the separate collection of packaging, the proportion may be lower today [48]. Concrete figures are not available. However, a significant increase in bulky waste is to be expected as discarded PVC building products from the stock are pressed into municipal waste management (see Section 4.1).

So far, today’s chlorine problem in the EU incineration plants has essentially been “solved” by dilution. In the various thermal processes in the waste sector, care is taken to ensure that the respective chlorine content in the plant input does not exceed a certain concentration. For example, in some waste incineration plants, PVC is also specifically regulated in the acceptance conditions (see [1]). In other plants, PVC mono-batches are carefully mixed in the bunker with other wastes using crane systems. In the case of co-processing, care is taken during the production of the RDF to ensure that the chlorine limits (see Section 4.5) are adhered, too, by mixing the various wastes.

‘Vinyl’ has informed us that it is possible to successfully separate the HCl or NaCl formed during waste incineration (RecoAcid, RecoSalt) [2]. However, it is politically unclear how and when this technology (wet flue gas cleaning) is to be introduced in the European Union (see [1]).

It must also be considered in light of the fact that waste incineration must and will change at the latest by 2050. In the EU, MSW incineration will be subject to emissions trading in the future, e.g., as is already the case in Germany (German Fuel Emissions Trading Act [49]). In June 2022, the European Parliament approved the inclusion of municipal waste incineration installations in the revised EU Emission Trading System to the EU-ETS Directive, starting in January 2026 [50]. Due to the likelihood that this regulation is on its way, plastics are expected to be partly separated prior to waste incineration. In this scenario, the operators of waste incineration plants would also attempt to reduce the input of PVC in parallel and not increase it.

A further increase in the PVC input of the European incineration plants to cope with the PVC- stock would, therefore, not be an option.

4.7. Landfilling of PVC

In the past, PVC’s high concentration of additives, particularly plasticizers, led to the pollution of seepage water and the surrounding area. There is still no strict landfill ban in the EU. According to the European Landfill Directive, member states may continue to landfill waste; this will only be limited to a maximum of 10% of the municipal waste generated from 2035 onwards. In some European countries (Germany, Austria, Switzerland (no EU member state)), the landfilling of high-calorific or other organic materials has been prohibited for years. The revision of the European Waste Framework Directive and the Landfill Directive in 2024 could provide the regulatory framework for a landfill ban by 2030.

Technically, PVC can be landfilled in large quantities. “Provided that landfills are operated appropriately and responsibly in accordance with present technical regulations, landfilling is an acceptable intermediate disposal option for PVC products” (ref. [51], p. 83). Even though disposal is prohibited in many European countries, these landfills can only be avoided in the long term if there is another option for solving the problem, and this is also implemented.

5. Conclusions

The question of regulatory requirements must be answered separately for the different stages of the life cycle of PVC. The most pressing problems and, therefore, also the priority need for regulation exist, as shown above, for the end-of-life phase. This is the reason why we start with this phase.

5.1. End-of-Life Phase

Obviously, none of the waste disposal processes currently in use (mechanical recycling, energy recovery) have sufficient capabilities to absorb the additional quantities of PVC from the stock. Therefore, the only solution for today’s PVC waste, and especially the stock problem that is heading towards the waste management sector, is to collect and dispose of PVC separately. Chemical recycling and mono-incineration have the potential to solve the stock problem in the future. However, this will require the construction of separate collection and industrial plants, which, in the case of chemical recycling, will technically need two stages in order to separate the chlorine as HCl in advance.

The creation of a plant infrastructure with which PVC could be processed would relieve the other parts of the waste management sector of chlorine massively. ‘Vinyl’ was clear to us at this point. “The European PVC manufacturers, converters and recyclers would be more than happy to process the waste if efficient logistic systems would exist to bring the waste to them”, and they “would welcome to make this separate collection mandatory” [2].

As shown above, ECHA rejects a phasing out of PVC, especially with the socio-economic argument of the low costs of PVC compared to alternative plastics/materials [5]. However, this argument is only applicable if the additional costs of the post-consumer phase—especially for the separate collection and disposal of PVC—are not taken into account. If included, PVC becomes an expensive plastic.

5.2. Production Phase

The regulatory requirements for the production phase are, in our opinion, sufficiently defined to ensure the protection of employees and consumers. The environmental organizations point out that several additives in PVC are not regulated, e.g., by REACH; due to bottlenecks of resources and data availability, the regulation of further PVC additives has not progressed further yet. The papers of the European Commission [4] and ECHA [5] fail—in their opinion—to address aspects that would justify or necessitate a corresponding need for regulation, such as quoting an authorization to be in place as a risk management measure, which does not consider the not unusual cases of non-compliance. Also, accidents during transport like the East Palestine, Ohio, train Derailment on 3 February 2023, where vinyl chloride was one of the primary chemicals of concern involved in the derailment [52], are not and have not been sufficiently addressed to this day. ‘Vinyl’ emphasized in this context that with vinyl chloride monomer (VCM), no fatal accident has happened in Europe for the past 40 years [2].

The EU Commission had planned a revision of the REACH Regulation—the current regulation dates from 2007—but was not able to implement this during this term of office. Whether and how (e.g. inclusion of polymers) REACH will be amended after the election of the European Parliament in June 2024 and the appointment of the new European Commission is currently not foreseeable.

5.3. Consumption Phase

For the consumption phase of PVC, there are a whole series of requirements for chemical legislation, both with regard to the plastic itself and, in particular, the additives used. The ECHA has drawn up a comprehensive catalogue of requirements in its Investigation Report, which we support, especially the required minimization of the releases of ortho-phthalates, prioritized PVC additives [34] and PVC microparticles (see Section 3).

Author Contributions

Conceptualization, writing—original draft preparation, U.L.; writing—review and editing, B.Z.-L. All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

The original contributions presented in the study are included in the article. Further inquiries can be directed to the corresponding author.

Acknowledgments

The authors would like to sincerely thank Christine Herrmann (European Environmental Bureau (EEB)), Klaus Günter Steinhäuser (Arbeitskreis Umweltchemikalien/Toxikologie beim Bund für Umwelt und Naturschutz Deutschland e.V. (BUND)), Charlotte Roeber and Vincent Stone (European Council of Vinyl Manufacturers/VinylPlus) and Geoffroy Tillieux (European Plastics Converters (EuPC)) for their valuable feedback.

Conflicts of Interest

Authors Uwe Lahl and Barbara Zeschmar-Lahl were employed by the company BZL Kommunikation und Projektsteuerung GmbH. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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Figure 1.Scenarios for the consumption of PVC products (compounds, excluding packaging) and subsequent waste generation in Germany; average service life: 34 years without packaging. Source: [26,27], adapted.

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