The debate over chlorine rages on.
This month we take a short look at another explosive issue: chlorine. Unlike pharmaceuticals (ACCN, January 1994), the debate does not seem to have captured the public's fancy as much, although unbleached or "chlorine-free" paper products have made inroads on consumers' buying habits. However, each side is working hard to convince the public of the credibility of their respective positions.
Two major U.S. business publications dealing with the chemical industry -- Chemical Week and Chemical & Engineering News (C&EN) -- have each featured chlorine as a theme in recent issues.
Whatever happens, the stakes are high. Chlorine represents an $8.5-billion industry in Canada supporting thousands of jobs. It is estimated that 85% of pharmaceuticals and 96% of pesticides are made with or contain chlorine. It is used to disinfect more than 90% of North America's drinking water. It is estimated that there are 15,000 chlorinated compounds in commerce.
The anti-chlorine campaigners received a boost when the International Joint Commission (IJC), the Canada-U.S. agency that advises the two governments how to keep the Great Lakes clean, recommended a ban on the industrial use of chlorine. However, the call for an outright ban was rejected by both governments.
Cancer of course is the biggest scare associated with chlorine and organochlorines. Other negative health effects have also been cited. These include adverse effects on the endocrine, immune and nervous systems in birds, fish and mammals. An Environment Canada report (SOE Bulletin No. 93-1), Toxic Contaminants in the Environment, notes that persistent organochlorines in the environment lead to bioaccumulation and biomagnification which may lead to the health threats noted earlier.
These concerns are not all new. Problems were first identified in the early 1960s. DDT is perhaps the most famous case. In 1972, general use of DDT was banned in the U.S. In the mid-1970s, most uses of DDT were banned in Canada although use of existing stock was allowed until 1990.
The pulp and paper industry has spent millions, if not billions, in the last 5 to 10 years to implement bleaching technologies which do not use elemental chlorine. This, of course, was in response to the dioxin/furan controversy. Bleaching with chlorine dioxide, oxygen, hydrogen peroxide or other substitutes is now the norm in most bleaching plants.
British Columbia, Ontario and Quebec have passed legislation that will drastically reduce organochlorine emissions from pulp and paper mills. B.C. and Ontario have set a zero discharge level by the year 2002. This will cost the industry several million dollars extra and its necessity/effectiveness is still a matter of controversy.
Greenpeace is in the forefront of the campaign against chlorine. Following what it feels were successful anti-chlorine campaigns in the pesticide and pulp and paper industries, it is turning its attention to polyvinyl chloride (PVC) plastic. (This is not to say Greenpeace will leave other industries alone if it feels they are polluters.) It claims PVC plastic is one of the most significant sources of dioxin generation. In a press release, it stated that PVC plastic is the preferred "sink" into which chlor-alkali producers "dump" excess chlorine to keep up with the growing demand for caustic soda.
Furthermore, Greenpeace noted that alternatives exist for all major uses of PVC.
On the other side is the Washington-based Chlorine Institute. In 1992, the Institute launched a major outreach program to answer growing criticism of the industry. It is emphasizing the benefits that chlorine provides to society, particularly in its role of protecting human health, and the "safe and responsible" manner in which the chlorine producers operate.
The Institute has also responded to the IJC recommendation and a proposed resolution from the American Public Health Association recommending the phase-out of chlorine. In its 1992 annual report, the Institute notes: "Efforts have concentrated on conveying the essential, scientifically supportable role of chlorine chemistry in society and the latest credible information pertaining to health and environmental issues." The resolution from the public health association was withdrawn.
However, in the C&EN article, April 19, 1993, author Bette Hileman points out that: ". . none of the efforts to phase out chlorine and chlorinated organics focus on all uses. None of them are directed at pharmaceuticals nor are any directed at chlorine use for producing inorganic chemicals. . . Most of the phaseout moves are aimed at organochlorines such as pesticides, PVC, CFCs, and solvents; and at the use of chlorine in the pulp and paper industry."
As with most things, this issue is a balancing act. Yes, chlorine and its extended family can be harmful, even deadly. Alternatives exist, but do they work as well and are their manufacturing processes and uses totally environmentally benign? What about the economics, or should these be considered at all when discussing potentially harmful effects on health?
The opponents of chlorinated organics give a blanket condemnation of them and claim that they should all be outlawed. Proponents of chlorine say the compounds should be studied one by one and that strong evidence of harm must be provided before bans should be considered.
On the other hand, opponents note that testing compounds individually would take too long and that potentially more harmful compounds, not yet tested, could take their place. They say that the weight of evidence already gathered about the harmful effects is sufficient to warrant a ban.
Donald MacKay, FCIC, University of Toronto, opposes this view. He said, "The chlorine issue merits very careful consideration by the chemical community. Whereas we accept the need to regulate specific compounds and metals, this is different. It is the first attempt to regulate an element or group as a component of a compound, regardless of the properties of that compound. Further, it represents an attempt by government to dictate the acceptability of chemical feedstocks, intermediates and processes as distinct from the industry's products and effluents."
The chemical industry and those that use chlorine are watching the debate anxiously. However, by taking note of the pulp and paper industry's actions in turning a problem into an opportunity, particularly in the marketing area, there are some valuable lessons to be learned.
Elf Atochem Saw the Trend
Elf Atochem North America Inc. is a US$1.7 billion diversified chemical manufacturer. It has recently invested close to US$100 million in its three chlor-alkali plants in the northwest U.S.: Tacoma, WA; Portland, OR; and Granger, WY.
The Portland and Tacoma plants produce chlorine and caustic soda electrolytically while the Granger plant is a chemical caustic operation. The Granger plant is on the site of the Trona ore mine, a joint venture with Texas Gulf Soda Ash. It can produce 100,000 tons per year of caustic soda. Combined, the three plants produce 400,000 tons of caustic soda annually.
The pulp and paper industry is Elf Atochem's largest single customer of electrolytic chlor-alkali products, taking at least 50% of production. The balance is used in the water treatment, refining, waste treatment and neutralization, metals (titanium and gold) industries.
British Columbia, particularly the pulp and paper mills, is an important market for Elf. About 25% of the chlor-alkali products produced at Tacoma are shipped to Canada.
The chlorine debate has affected Elf "profoundly", according to chlor-alkali business manager Billy Tullos. Many pulp mills have reduced or eliminated their use of elemental chlorine. Pulp produced without chlorine is marketed as ECF (elemental chlorine free) and uses high substitution rates (70% sodium chlorate). Others use no chlorine or chlorates at all -- TCF (totally chlorine free) -- by bleaching with ozone or hydrogen peroxide.
"It is the wave of the future," Tullos admitted. The company makes chlorates and hydrogen peroxide, striving for a balanced approach as it sells less chlorine.
"We saw the trend coming," Tullos added, "and we needed to have a source of out-of-balance caustic. That's when we decided to build Granger, to ensure an adequate supply of caustic for the pulp and paper industry."
Caustic soda is produced via two unique routes. One involves the electrolysis of salt to form both chlorine and caustic in a ratio of 1 to 1:1 respectively. This combined production is called an ECU (electrochemical unit). The other method uses a chemical reaction of soda ash (sodium carbonate) with lime (CaO) to form caustic soda. Historically, the pulp and paper industry was a large buyer of ECUs since it used both chlorine and caustic soda in fairly balanced amounts. With the reduction in chlorine consumption, more of the caustic soda used in the pulp and paper industry is now considered out of balance (OOB).
Work at the Tacoma and Portland plants included environmental and safety improvements and switching to membrane caustic cells in some cases. The use of membranes reduces energy use and improves product quality.
There are several different types of electrolytic cells used to produce ECUs. There are mercury-based cells, membrane cells and diaphragm cells. Mercury and membrane cells offer some advantages in caustic soda quality and lower electricity use. Mercury cells are not in favor with newer production facilities due to the concern of mercury contamination.
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|Title Annotation:||includes related article on Elf Atochem North America Inc.|
|Publication:||Canadian Chemical News|
|Date:||Mar 1, 1994|
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