chemical facts


/ chemical facts/ textiles: the bad

Textiles are made from fibres which are small hair-like structures which can be twisted together to form a yarn. All fibres are made from chemical units called polymers, which are formed from single-molecule units called monomers, linked together like a bead necklace to form long chains. Fibres from plants and animals are constructed from polymers, which occur naturally. Cellulosic man-made fibres are formed from the natural polymers of plants (cellulose). The cellulose is dissolved and then forced through spinning jets. Synthetic man-made fibres are derived from petroleum products. Their polymers are formed synthetically (artificially) by chemical reactions. The common feature of all fibres is that they are constructed from polymer molecules, which lay alongside each other and are bonded together.

Agricultural Fibres
Agricultural fibres are any type of plant or animal that is raised as a crop for the purpose of growing fibres for textile manufacture.  This includes: cotton, hemp, linen, jute, flax, wool, cashmere, leather and all variations of cotton.  Plant fibres are made of woody cellulose substances and are often referred to as cellulosic fibres. Some of the fibres are part of the transport system that carries water, minerals and waste products around the plant. The production of these fibres often relies heavily on the use of pesticides and other chemicals. In addition the abundant use of water needed to cultivate some of these textiles is also an issue.  Genetically modified (GM) cotton crops are raised as an alternative to harsh pesticide use, although genetically modified cotton does not eliminate the use of pesticides and weed killers and has a damaging effect on biodiversity. 

The term “Man-made” incorporates all textiles not of natural origin as provided by nature, but produced by chemical treatment of certain raw materials. The main sources are wood pulp, cotton linters (the short staple lengths from the cotton boll which are unspinnable), petroleum extracts and by-products of coal. Man-made fibres can be divided into two categories: cellulosic, which are fibres made from a natural base such as acetate and viscose; these fibres are often referred to as “regenerated” fibres, and non-cellulosic, which are fibres made from a chemical base, such as nylon, polyester and acrylic; these fibres are often referred to as “synthetic” fibres.

Cellulosic Fibres
Cellulose is a chemical found in plants. To make fibres for textiles, the cellulose is extracted and mixed with a number of chemicals. These chemicals vary, depending on the fibre to be made, but the end result is similar – a thick liquid which is then forced through the tiny holes of a spinneret to form threads. These threads are then hardened in acid and twisted into yarn, or spun then twisted into yarn, depending on the type of fibre being produced.

Non-Cellulosic Fibres
These fibres are made from chemicals only. Tiny molecules, known as monomers, are joined into units which are in turn built into long chains called polymers. This process is called polymerisation. A liquid is formed by either heating or dissolving the chemicals, depending on the fibre being made, and the liquid is forced through a spinneret and spun into a yarn.

Conventional cotton is made from a natural fibre, from a plant, but growing cotton requires the use of acutely toxic pesticides, herbicides and fertilizers. The cultivation of conventional cotton uses 22.5% of the world's insecticides and 10% of the world's pesticides (Environmental Justice Foundation, 2010). Growing cotton accounts for only 3% of all cultivated land, but uses 20% of all chemical pesticides used. Eight times more chemicals are used on cotton than on an average food crop. The Ethical Fashion Forum states on its website that it takes approximately 150 grammes of chemicals to grow enough cotton to make just one t-shirt; another company, Aura Herbal Wear, estimates that up to 8000 different chemicals are used in various stages of chemical dyeing.

Evidence indicates that cotton is the second most pesticide-laden crop in the world, and many of these pesticides are known cancer-causing chemicals. (Environmental Justice Foundation, 2010) Common pesticides used in conventional cotton cultivation include:

Aldicarb, a powerful nerve agent, is one of the most toxic pesticides applied to cotton worldwide and the 2nd most used pesticide in global cotton production.

Aldrin – A pesticide applied to soils to kill termites, grasshoppers and other insect pests.

Chlordane – Used extensively to control termites and as a broad-spectrum insecticide on a range of agricultural crops including cotton.

Deltamethrin a nerve agent is applied in over half of the cotton producing countries.

Dieldrin – Used principally to control termites and textile pests, dieldrin has also been used to control insect-borne diseases and insects living in agricultural soils.

Endosulfan is widely used in cotton production and is the dominant pesticide in the cotton sector in 19 countries.

Endrin – This insecticide is sprayed on the leaves of crops such as cotton and is also used to control mice, voles and other rodents.

Heptachlor – Primarily employed to kill soil insects and termites, heptachlor has also been used more widely to kill cotton insects, grasshoppers, other crop pests, and malaria-carrying mosquitoes.

Monocrotophos Despite being withdrawn from the US market in 1989, it is widely used in developing world countries.

Toxaphene – This insecticide, also called camphechlor, is applied to cotton, and has also been used to control ticks and mites in livestock. (United Nations Environment Programme, 2005)

Pesticides and synthetic fertilizers are known to be harmful for the environment and the people who interact with them. According to the World Health Organization, 20,000 deaths result from pesticide poisoning in third world countries each year and death by starvation is also alarmingly prevalent. Pan UK estimate that 200,000 cotton farmers commit suicide annually due to spiraling debts incurred from buying pesticides and a further 1,000,000 people a year suffer from long-term pesticide poisoning.

While developing countries account for less than 30% of global pesticide consumption, the bulk of pesticide poisonings occur in the developing world, where pesticides are used by poor farmers without the knowledge, training, and protective equipment to use them correctly, so as to minimise contamination (Pan UK, 2010). The International Code of Conduct on the Distribution and Use of Pesticides (2002) of the United Nation’s Food and Agriculture Organisation recommends that hazardous pesticides, including many of the pesticides used on cotton, “should be avoided by small-scale users in tropical climates, considering the lack of availability of appropriate safety equipment”.

According to the Environmental Justice Foundation, some 175 million children around the globe are employed in agriculture, where they are at risk from exposure to pesticides and other chemicals, and are at risk of injury from machinery and arduous labour. Children are employed in a variety of tasks including cottonseed production, harvesting the cotton and pesticide spraying. Children are particularly vulnerable to poisoning, and are often the first victims of pesticide poisoning, even if they do not participate in crop spraying, due to the proximity of their homes to cotton fields or because of the re-use of empty pesticide containers.

The use of pesticides has caused a range of well-documented environmental impacts including reduced soil fertility and loss of biodiversity, but they also pose other health risks.  Medical research has shown that some pesticides have the potential to affect nervous, hormonal or immune systems. According to Pan UK, there are many studies showing that chronic exposure to pesticides may increase the risk of a wide range of serious health problems, including certain cancers such as leukaemia, lymphoma and brain cancer, neurological problems such as Parkinson’s disease, diabetes, respiratory diseases, some birth defects, spontaneous abortions and reproductive problems such as reduced sperm count and sterility, decreased intelligence, behavioral abnormalities and a weakened immune system. Other symptoms of pesticide poisoning can include: skin and eye irritation, chills or fever, sweating, numbness, tingling sensations, muscle spasms, seizures, paralysis, headache, dizziness, fatigue, breathing difficulties, changes in heart rhythm, nausea, vomiting and diarrhea.

The extent of the impacts of cotton production varies however, according to cultivation practices and local conditions. According to the Environmental Justice Foundation:

“Hazardous pesticides associated with global cotton production also represent a substantial threat to global freshwater resources. Hazardous cotton pesticides are known to contaminate rivers in USA, India, Pakistan, Uzbekistan, Brazil, Australia, Greece and West Africa”.

Image: Spraying Pesticides by Sura Nualpradid :

Linen is one of mankind’s oldest fabrics and is known to have been used for textiles from as early as the Stone Age period. Linen is produced from the leaves and stalks of the flax plant, which is a small plant with blue flowers grown in many temperate and subtropical regions. To make linen, the plant needs to be pulled from the ground as some of the most valuable parts of the plant are in the lower stem and roots. The stalks with roots attached are soaked in tanks of water, open ponds or running river water until the green part rots away; this process is called retting.

The customary process of retting, or de-gumming flax fibres from the stalk, involves the release of nutrients from the decaying stalks, which is highly polluting to water. The chemicals used for retting are also polluting if not neutralized before being released into water supplies. The retting process is traditionally done by manual methods which are highly labour intensive and slow, however this does provide ecological benefits, but retting can also be achieved significantly faster using mechanical turning or by using chemicals, such as soda ash, but this saves time at the expense of quality.

Once extracted and dried, the fibres are scraped to remove any dirt, then combed, leaving the fibres straight and parallel, ready to be spun and woven into linen. The long, fine fibres are spun into yarns which are often uneven, depending on the retting method used. The fibres are harder than cotton to spin and weave, which ultimately contributed to the demise of linen in favour of cotton during the Industrial Revolution.

One of the most critical steps in the production process of linen in terms of ecology is the washing, bleaching and finishing of the fabric. The natural colour of linen is off-white to shades of light brown, therefore the majority of linen requires bleaching, which takes place by chemical means, however traditionally this would have been achieved by laying it out in the field for natural bleaching by the sun.

Flax fibres are smooth, although stiffer and harder than cotton and are therefore less supple. Linen fabrics have very poor elasticity and a tendency to crease and are therefore often coated with resins or formaldehyde compounds for a crease-resistant finish.

Wool is the soft, warm, springy hair that grows on sheep. It grows in the same way as human hair. Small cells grow from the root of the hair and gradually die. Under a microscope, the fibres look scaly and crinkly. Some breeds of sheep are better for meat and some breeds are noted for the special quality of their wool; the best wool coming from Australian Merino sheep. Lambswool comes from the first fleece sheared from a lamb and produces the softest and finest wool fibres.

The biggest impact from wool comes from the vast amounts of water and powerful detergents and solvents that are required to clean it before it is processed into yarn, as in its raw state it contains many impurities and is both dirty and greasy. Cleaning, called “scouring” produces an effluent in the form of wool grease sludge, which contains high suspended solids and is highly polluting, traditionally it is reclaimed from the scouring process for use as lanolin. Kate Fletcher states in her book “Sustainable Fashion and Textiles: Design Journeys” that “For each kg of scoured wool, 1.5kg of waste impurities are produced”.

In the traditional manufacture of wool and the farming of sheep for their fibre, the sheep are kept in large herds on small plots of land.  This generally leads to overgrazing of the fields, which leaves the sheep more susceptible to disease and infection.  To counter this, pesticides and vaccinations are used that are moderately toxic to humans, amphibians, birds, and the sheep.  Injectable insecticides or pour-on preparations are used in the treatment of disease, however most sheep are dipped in a pesticide bath to control parasite infections, which if managed badly, can cause harm to human health, pollute streams, ground water, and drinking water from runoff. 

At one time the use of pesticides for sheep dipping was compulsory in the UK; organophosphates which have been linked to severe nerve damage in humans were widely used in the UK until recently to treat sheep scab, and have been found to persist in the environment for years. Their replacement however, dips based on cypermethrim (a pyrethoid), which are safer for farmers, have been linked to a significant growth in water pollution.

Wool is usually dry-cleaned or hand-washed to avoid felting and shrinking, however dry cleaning uses detergents and liquid solvents, the most common of which is perchloroethylene, a petrochemical based solvent which is a hazardous air pollutant that is heavily regulated. Research has shown that high doses of exposure over long periods can affect the central nervous system and cause damage to the kidneys, liver and reproductive system.

Machine-washable wool was made possible by the development of a chlorination pretreatment and unfortunately, this process results in wastewater with unacceptably high levels of absorbable organohalogens, or (AOX), which are toxins created when chlorine reacts with available carbon-based compounds. Dioxins, a group of AOX, are one of the most toxic substances known; they can be deadly to humans at levels below 1 part per trillion.


Images: Silk Factory, by Phill Gowen©

Silk is produced by silkworms, which are caterpillars of several species of moth. The most important species is the Bombyx mori which lives in mulberry trees. The silk comes from the caterpillar’s chrysalis, or cocoon. As silk quality is highly related to a worm’s diet, most commercially produced silk requires feeding the silkworms a carefully controlled diet of mulberry leaves, which are grown under special conditions and are carefully picked by hand. The mulberry trees require fertilizer and pesticide applications, although far less than in cotton production, and as the worms are very sensitive to poisoning by agrochemicals and other inputs, a supply of clean air and careful climate control are needed to ensure maximum yields.

Cultivated silk comes from silkworms raised in production facilities and the worms are killed before leaving the cocoons as moths in order to prevent damage to the cocoons. It takes a silk worm 3-4 days to spin a cocoon around itself, which is made out of a single continuous thread which can be up to 1 kilometre in length.  In silk farms, the fibres are extracted by steaming the cocoons, or they are boiled alive in order to preserve the entire spun cocoon. Once the fibres are extracted a harsh degumming process using detergents is used to clean and bleach the fibre, to loosen the gum and give access to the thread. The waste water is usually discharged to ground water, acting as a low level pollutant.

Viscose is a viscous organic liquid which is used to make rayon and generally the term “viscose” is synonymous with the fibre rayon, or viscose rayon. Rayon is a manufactured regenerated cellulose fibre. Because it is produced from naturally occurring polymers, it is neither a truly synthetic fibre nor a natural fibre; it is a semi-synthetic or artificial fibre.

Viscose production requires the cellulose to be purified and bleached and then soaked in sodium hydroxide before it is treated with carbon disulphide and finally spun in a solution of sulphuric acid, sodium sulphate, zinc sulphate and glucose. The production of viscose generates emissions to air from the sulphur, nitrous oxides, carbon disulphide and hydrogen sulphide and emissions from the process to water result in high pollution indexes which are detrimental to the environment if discharged untreated.

Polyester is a synthetic fibre and is manmade from petrochemicals.  Synthetic fibres are processed through a series of highly toxic chemical processes and do not decompose naturally.  The main chemicals used in the production of polyester are terephthalic acid (TA) or dimethyl terephthalate, which are reacted with ethylene glycol. Polyester fibre manufacture also involves a process of purifying TA and is based on bromide-controlled oxidation.

Environmental damage from the production of polyester can be caused through emissions to air, and if water is used in the process and discharged untreated, it can include: heavy metal cobalt; manganese salts; sodium bromide; antimony oxide (which is licensed, despite it being a known carcinogen); and titanium dioxide.

Nylon or polyamide fibres are also made from petrochemicals. In the production of nylon, raw materials including hexamethylendiamine and adipic acid are combined to form a polyamide salt. The two chemicals react under high pressure and heat to create a polymer that is then extracted and cooled with water. The production of nylon is known to be energy intensive and also produces emissions of nitrous oxide, which is a potent greenhouse gas.

Acrylic fibres, like other synthetic fibres, are made from mineral oil or other hydrocarbons. Acrylonitrile is forced to react with various combinations of process chemicals including styrene, vinyl acetate, ammonium persulphate and iron, among others to create the acrylic polymer, which is then solvent spun, washed in hot water to remove residual solvents and salts, drawn into tanks of near to boiling water (to give the fibre strength), and then finished by immersion in an acid bath, to give the fibre an anti-static treatment and then dried. The main environmental impacts of acrylic production are due to the significant number the chemicals used in its production, which have a high potential for creating environmental problems if discharged untreated.

Polyvinyl chloride (PVC) is often used on motifs/prints in clothing and is also commonly used in sports shoes. It contains phthalates which are mainly added to give a softer shape to stiff plastics. Some phthalates are known endocrine disruptors and there is an increasing body of research showing that they may be implicated in a range of health issues relating to male reproductive development in utero, general increases in male reproductive impairment and the early onset of puberty and premature breast development in young girls. (Sharpe and Irvine, 2004: 447-451). Currently, the Phthalates Directive permits the use of the phthalates di-isononyl phthalate (DINP), di-isodecyl phthalate (DIDP) and di-n-octyl phthalate (DONP) and nonylphenol in children’s products, if they are not designed to be put into the mouth.

In addition to phthalates, some of PVC’s other disturbing ingredients include: chlorine, petroleum, lead and the carcinogen Di-(2-ethylhexyl) Phthalate (DEHP). The production process also uses volatile organic compounds (VOCs), which are often recognized as that “new car smell”, which are associated with headaches, fatigue, nose and throat discomfort, and some are suspected to cause cancer. Lead is also a known toxin linked with cancer, infertility, Alzheimer’s, and a host of other health problems.

Other uunintentional chemical by-products such as polychlorinated dioxins and furans are also produced from industrial processes in the production of PVC. Dioxins are linked with immune, reproductive, nervous, and endocrine system damage and along with furans are the most potent cancer-causing chemicals known; they gained worldwide attention in the late 1990s when they were found to have contaminated chicken meat in several European countries, (Greenpeace, 2007).


Images: Tanning Leather in Fez, by Alison Moss©

The tanning process for leather is an extremely toxic process that can involve cyanide, arsenic, and other chemicals linked with nervous disorders, asthma, skin and respiratory disorders, among others. Tanning produces waste (the hair, salt, and a slurry of insoluble matter present on the animal’s skin before it is tanned), that if dumped into the environment and can poison waterways.

Many people assume leather is a by-product of the meat industry, but this is a common misconception; cows for leather are often completely different to those used for meat, which means more water, land, and other resources are used to raise and slaughter these cows. Furthermore, like all textile fibres, pollution is also generated when they are shipped around the world.

Image: Tanning Leather in Fez, by Alison Moss©



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/ textiles: the bad

/ textiles: the ugly

/ sustainable textiles

/ REACH legislation

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