At a conference in Monte Carlo in October, 500 senior representatives of the chlor-alkali industry gathered in a waterfront hotel to discuss the industry's environmental problems. Outside, the Greenpeace ship Sirius sailed to and fro trailing banners proclaiming "Chlorine Kills - Ban PVC".
This symbol of an industry under siege is an accurate one. Until recently, the environmental problems caused by organochlorines had been addressed in a piecemeal fashion by environmentalists. But Greenpeace now claims that they are causing such widespread damage that "the only hope is to halt the flow of organochlorines into the natural world completely" - in other words, to shut down the chlorine industry.
A sunset industry?
The group's call for a phase-out is not unprecedented. One of the most seriously affected - and also intensively studied - regions is the North American Great Lakes. Earlier this year, the International Joint Commission on the Great Lakes, a scientific body which advises the US and Canadian governments, recommended that timetables be developed "to sunset the use of chlorine and chlorine-containing compounds as industrial feedstocks and the means of reducing or eliminating other uses be examined."
Chlorine producers accept that some notorious pollutants such as PCBs and DDT have caused severe environmental damage. But, they maintain, the most dangerous chemicals are now either being phased out or closely regulated.
Although the campaign has been under way for about two years, there has been no sign of a meeting of minds between the antagonists. While the group has focussed its attentions on the damage caused by organochlorines, chlorine producers have been defending themselves in time-honoured fashion by stressing the importance of their products and the lack of suitable alternatives.
The industry's defensive stance is easy to understand. Environmental pressures have been squeezing chlorine production and the markets for some of its key products for several years.
In north-west Europe, chlor-alkali producers face a sizeable bill to meet the target of phasing out their traditional mercury cells by 2010 agreed at the third North Sea Conference in 1990. Some 70% of western Europe's chlor-alkali plants still use this technology. ICI estimates that it will cost £200 million to convert its four UK mercury cell plants to the membrane process. And Dr Dieter Becher of Bayer says that an investment of DM1 million will be needed for every one kilogramme reduction in annual mercury releases.
In the UK, chlor-alkali producers are facing a more immediate threat. ICI's chlorine plants alone consume almost 1% of the electricity generated in the UK. Having benefitted from price discounts for bulk users before electricity privatisation, its £60 million annual power bill has risen by 60% in the last 18 months, threatening the viability of any reinvestment in mercury-free cells. The proposed EC carbon/energy tax is unlikely to be a thrilling prospect for the company either.
Of the pressures on chlorinated products, the most intense is the impending phase-out of ozone-depleting chemicals. Consumption of CFCs and methyl chloroform is likely to be banned from the beginning of 1996, and possibly a year earlier, within the EC. The loss of this significant outlet for chlorine will only be eased marginally by the switch to HCFCs.
Another traditional outlet for chlorine has been the pulp and paper industry. In 1986, it consumed 13% of world chlorine production. But curbs on discharges of dioxins and other organochlorines have driven a move towards alternative bleaching processes. Charles Stewart, Executive Vice-President of Occidental Chemical, predicted in Monte Carlo that the sector will consume only 9% of chlorine output by 1994.
Chlorinated solvents are also under regulatory pressure. The European Commission has classified them as one of its priority waste streams. By 2000, it is hoping to achieve a 35% reduction in the consumption of chlorinated solvents and improved recycling of those remaining in use.
According to the European Chlorinated Solvents Association, western European consumption of the products has already been halved since 1974. Even so, the list of environmental problems caused by chlorinated solvents continues to lengthen. Discharges from ICI's works in Cheshire have resulted in prosecutions by the National Rivers Authority and are causing exceedances of EC water quality standards (ENDS Report 207, pp 4-6 ). And the number of groundwater pollution incidents caused by chlorinated solvents is growing (ENDS Report 211, pp 37-38 , and this issue, pp 6-7 ).
The use of chlorine for drinking water disinfection is periodically called into question - most recently following a study suggesting that chlorination by-products can cause rectal and bladder cancers (ENDS Report 210, pp 9-10 ). Both the industry and the World Health Organisation insist that any risk is outweighed by the dangers to health of non-treatment. Indeed, a recent cholera epidemic in Peru which followed the suspension of chlorination of water supplies is regularly cited by the industry to illustrate the value of its products.
However, drinking water disinfection accounts for less than 5% of chlorine consumption. In western Europe, 80% of the gas is used to prepare organochlorine products or intermediates. It is here that the real battle is being fought.
Before 1988, global chlorine demand grew at a steady rate of some 4% per year and reached 36.5 million tonnes in 1991. But Occidental's Charles Stewart expects that because of "real or perceived environmental concerns", demand will grow at less than 1% per year for the foreseeable future. In Europe, Canada and Japan - which account for 50% of world production - he predicts that output will shrink by up to 5% per year.
Chlorine production is only one half of the equation. For every tonne of chlorine, roughly 1.1 tonnes of caustic soda are produced. Traditionally the chlor-alkali industry has struggled to balance supply and demand in both these markets, but the pressures on chlorine are likely to tip the scales permanently.
Caustic demand is at present depressed by the recession, but is likely to pick up. As a result, there is growing interest in using soda ash as a replacement for caustic soda, although this is limited to uses such as phosphate production and the pulp and paper industry. Alternatively, caustic soda can be made by causticizing soda ash. Jean Christiaens, Managing Director of Solvay's alkali division, says that this route is already profitable, although "in the current climate the long-term profitability of causticized soda ash cannot be guaranteed."
PVC's crucial role
Chlor-alkali producers are hoping to keep their share of the caustic market and to even out chlorine/caustic imbalances by channelling more chlorine towards PVC production. According to Charles Stewart, growth in chlorine in the 1990s will depend on rising world-wide demand for PVC. This is already expected to consume as much as one-third of total chlorine output in the next two years.
The industry is therefore placing many of its eggs in the PVC basket - but this option is also under fire. Greenpeace claims that PVC is hard to recycle cleanly and can lead to dioxin formation when incinerated. In Austria, the group is being sued by PVC producers for producing advertising hoardings describing PVC as an "environmental poison."
The chlorine industry certainly cannot be confident that demand for PVC will be sustained, at least in developed countries. In Germany, over 50 local authorities have introduced a PVC phase-out programme for public buildings. And the Swedish furniture distributor IKEA has announced that it intends to phase out PVC products.
North Sea action plan
The latest bad news for chlorine producers came in September, when Environment Ministers meeting in Paris to sign a new Convention on the protection of the North Sea and north-east Atlantic put organochlorine pollution firmly at the top of its agenda (ENDS Report 212, pp 29-30 ).
In a late addition to an action plan which will be implemented by the existing Paris Commission before the new Convention comes into force, Ministers gave "priority to the substantial reduction of inputs to the marine area of organohalogen substances which are toxic, persistent and liable to bioaccumulate, with the aim of their elimination." And an accompanying ministerial declaration said that such substances should, "regardless of their anthropogenic source, be reduced, by the year 2000, to levels that are not harmful to man or nature with the aim of their elimination."
The action plan also commits the Paris Commission to prohibit the use of organohalogens which are "unnecessary for the intended use or process", and to compile a list of substances and processes which are suitable as substitutes.
Environmentalists welcomed these moves, but the chlorine industry was caught on the hop. Andrew Butler, President of Dow Europe, described the focus on organohalogens as "an insensitive, political conclusion".
In the long-term, the survival of the chlor-alkali industry depends on two crucial questions. Do all organochlorines present a serious and lasting threat to the marine environment? And if not, can the release of the dangerous chemicals be prevented without closing down the entire industry?
The Greenpeace case...
Greenpeace has no doubts on either issue. In its recent report "Death in Small Doses", it argues that organochlorines are "arguably the most dangerous group of chemicals to which natural systems can be exposed." The report says that some 11,000 organochlorines are known to be produced and used commercially - and claims that "all of them affect aquatic life".
The report summarises a long list of studies which implicate organochlorine compounds in damage to marine ecosystems. It lists impacts on all levels of marine life from plants and invertebrates through to the higher aquatic mammals. It concludes that marine mammals are particularly susceptible to organochlorine contamination because they have large blubber reserves in which the chemicals tend to concentrate.
Greenpeace is most worried about the possible effects of organochlorines on the hormone, immune and reproductive systems. This interference, it claims, can lead to reduced birth rates and fertility, abnormal development and population crashes. The most recent marine mass mortalities were the deaths of several thousand striped dolphins in the Mediterranean in the summers of 1990 and 1991. Greenpeace accepts that the role of organochlorines in mass die-offs is still the subject of debate. But it notes that post mortem analyses of the Mediterranean dolphins found PCB levels of 500-3,000ppm and average DDT levels of 432ppm.
...and industry's rebuttal
The report has drawn an angry response from industry, particularly for its extrapolation of the effects of individual organochlorines to the entire group. Dr Ian Campbell, an environmental scientist with ICI Chemicals and Polymers, says that the studies quoted by Greenpeace to show adverse environmental effects almost entirely concern just five classes of chemicals - PCBs, DDT, CFCs, dioxins and the "drins" group of insecticides. "Greenpeace only offers evidence on five groups of compounds," he says, "but is tarring everything with the same brush. It's as ridiculous as condemning all phosphorus compounds because nerve gases happen to be phosphate esters."
All of the five groups are already under some form of control. In the EC, PCBs, DDT and the drins are banned, and CFC production will cease by the end of 1995 at the latest. Dioxins are more difficult to control due to the wide range of possible sources. However, industry points to strict incoming controls on incineration which should reduce dioxin emissions.
Greenpeace's assertions that "organochlorines are highly toxic" and that "organochlorines tend to concentrate in living tissue" are undoubtedly sweeping generalisations. The same can be said of its claim that "many of the most damaging effects on biological systems are common to virtually all organochlorines. These compounds share the same dangerous general characteristics of toxicity and persistence."
Paul Johnston, editor of "Death in Small Doses", agrees that the report deals mainly with the effects of well-documented compounds but argues that they are the only substances which have been extensively studied in the environment. "If you extract all of the organochlorines from seal fat," he says, "only some 40% belong to the known categories. The rest remain unidentified - but PCB levels tend to be a good index of total environmental contamination."
Dr Johnston argues that the lack of data does not mean that there is no problem, and points out that the accumulation of PCBs in nature only came to light when they showed up as interference in tests for DDT contamination.
The possibility that as yet unknown organochlorines may be accumulating in the environment is backed up by a recent Canadian study.1 Tris(4-chlorophenyl)methanol (TCP methanol) was found in marine mammals and bird eggs from the Arctic, Antarctic, Australia and North America. The highest levels were found in polar bear livers at a mean of 5,200µg per kilogram of body fat. A related compound, TCP methane, was found in peregrine falcon eggs.
There is as yet no information on the environmental effects of these chemicals. But TCP methanol was detected in fat samples dating back to 1952, and its concentrations were shown to correlate with the occurrence of other high molecular weight organochlorines, particularly PCBs. The researchers say that possible sources include the production of certain agrochemicals, polymers and synthetic dyes.
A further cornerstone of Greenpeace's argument is that "organochlorines, once released into the environment, react to form any number of other unwanted and potentially highly damaging organochlorines." The most obvious example is the breakdown of DDT in mammals and birds to form the toxic derivative DDE. Apart from this case, however, support for Greenpeace's statement is scanty - a Swedish paper showing the methylation of chlorophenols in bleach effluents and other research showing the possibility that trichloroethane in groundwater may degrade to vinyl chloride.
"Greenpeace can't have it both ways on persistence and degradability," says David Taylor of ICI's Brixham Laboratory. He argues that chemicals such as PCBs are almost totally unreactive and are therefore persistent, but most organochlorines are metabolised to less toxic materials. "The mere fact that a compound has a carbon-halogen bond tells you absolutely nothing about its properties," he says.
Industry's favourite illustration of this point is chloroform. Although this is regulated as a "black list" substance by an EC Directive, it has a bioaccumulation potential of zero, is toxic only in high concentrations, and does not persist in the aquatic environment because of its volatility, says David Taylor. In the atmosphere, chloroform degrades with a half-life of 20 weeks - and furthermore emissions from marine algae mean that less than 5% of emissions are man-made. Only if the substance is discharged at high concentrations to watercourses or groundwater is it likely to cause pollution problems, he contends.
Black and red lists
The European Commission's slow progress in regulating other, more hazardous, organochlorines as "black list" substances has fuelled the anti-chlorine lobby. EC Directives dealing with just 15 of these compounds have been adopted since 1976.
In the UK, the Government attempted to develop its own controls with the publication of its "red list" of priority water pollutants in 1989. The Department of the Environment defined parameters to assess toxicity, persistence and bioaccumulation with the aim of identifying the most dangerous substances on the EC's list of 129 candidates for "black list" status. The "red list" contains 22 chemicals - but adequate scientific information was lacking for a further 23 substances which were thought to qualify, many of them organochlorines.
The "red list" was an important attempt to identify the most dangerous water pollutants. "Nobody has seriously bitten the bullet of defining toxicity, persistence and bioaccumulation," says ICI's David Taylor. "Until they do, Greenpeace can get away with saying that everything is environmentally significant."
Data gathering programme
Moves are now underway at EC level which may help to plug the gaps in scientific database on the effects of chemicals in the environment. In 1981, the "Sixth Amendment" Directive came into effect, requiring the testing of new chemicals for potential hazards. And in December last year, Environment Ministers agreed a new Regulation to set up a risk assessment programme for "existing" chemicals - those not covered by the Sixth Amendment (ENDS Report 204, pp 20-23 ).
The Regulation, which should be formally adopted early next year, will require all available data on high production volume chemicals to be submitted to the Commission. Substances considered to be a priority will be assigned to Member States for detailed risk assessment - but first additional rules defining a common approach to risk assessment will be needed. The threshold criteria for toxicity, persistence and bioaccumulation are therefore still unknown.
The first phase of data collection for chemicals produced in quantities over 1,000 tonnes per year by any given company is already under way. The second phase will require more limited data on chemicals in the 10-1,000 tonnes per year range.
The programme will inevitably be time-consuming, but could help to provide valuable data on the hazards of organochlorines. But Greenpeace's Paul Johnston is sceptical. "For all the good intentions," he says, "this will end up acting as a delaying tactic. In two years' time we'll have a huge list of priority chemicals but will be no closer to biting the bullet."
It is not yet clear what approach the Paris Commission will take in implementing the action plan agreed by Ministers in September. However, some clues may be found in a Decision on the phasing out of PCBs and hazardous PCB substitutes which was also adopted at the meeting.
The Decision contains threshold criteria for a preliminary assessment of the environmental risk of PCB substitutes. Only the degradability criterion is stricter than that used by the UK in drawing up its "red list" (see table ).
If these criteria are applied in assessing organochlorines, the stronger emphasis on environmental persistence is likely to widen the net considerably. This is particularly important as, under the Decision, a compound will be ranked as being of "high concern" even if it only meets one of the above criteria. Where data are missing, the Decision says that a high level of concern should be registered.
Meanwhile, the chemical industry is warning that a chlorine ban would be much more far-reaching than the loss of chlorinated products from the marketplace. In Germany, the industry estimates that over 60% of its sales depend either directly or indirectly on chlorine chemistry. Bayer's Dieter Becher argues that chlorine intermediates are essential in the preparation of many end-products that are themselves not organochlorines.
In 1989, 770,000 tonnes of chlorine entered Bayer plants in Germany, mostly as salt. After processing, 510,000 tonnes were discharged into the Rhine or Elbe, also as chloride ions. Some 4,000 tonnes went directly to landfill as organic or inorganic waste, while 173,000 tonnes left Bayer's sites to go to other chemical companies as intermediates for further processing. Only 83,000 tonnes, or 11% of the incoming chlorine, left Bayer's plants in products destined for the end user. However, Bayer is an unusual case in that it does not produce PVC or halogenated solvents.
It is the release of chlorinated end-products into the environment which is under the most immediate pressure. The imposition of strict pollution controls could serve to take the pressure off the manufacturing sites. Indeed, a switch to cleaner processes may help chlorine producers to deflect attacks away from the use of organochlorines as intermediates.
The chlorine industry's representatives gathered in Monte Carlo were offered one consolation by Peter Stief-Tauch, a senior official in the European Commission's Environment Directorate. The Commission, he said, "has no intention of phasing out chlorine as a raw material. What we are after is environmentally safe production and the safe use of products with production phase-outs in special cases." That may have been regarded as cold comfort by an industry which has lately developed a habit of losing many crucial environmental battles.