Synthetic Dyes: A look at Environmental & Human Risks

By Brit

Since antiquity, fabrics have been dyed with extracts from minerals, plants, and animals. In fact, dyeing historically was a secretive art form; the most beautiful and exotic pigments reserved were for those who had the status to wear them.

Things began to change around 1856 when scientists discovered how to make synthetic dyes. Cheaper to produce, brighter, more color-fast, and easy to apply to fabric, these new dyes changed the playing field. Scientists raced to formulate gorgeous new colors and before long, dyed fabric was available to all, and natural dyes had become obsolete for most applications. See Encyclopedia Britannica for more details.

This brightly colored, changed new world was not without a down side however. The chemicals used to produce dyes today are often highly toxic, carcinogenic, or even explosive. The chemical Anililine, the basis for a popular group of dyes known as Azo dyes (specifically group III A1 and A2) which are considered deadly poisons (giving off carcinogenic amines) and dangerous to work with, also being highly flammable. In addition , other harmful chemicals used in the dying process include

1) dioxin – a carcinogen and possible hormone disrupter;

2) Toxic heavy metals such as chrome, copper, and zinc – known carcinogens; and

3) Formaldehyde, a suspected carcinogen.

Dye chemicals have caused or fueled many dye factory fires through history, including a massive Rhode Island dye factory fire in 2003 in which vast quantities of dye chemicals spilled into the Blackstone River.

Dangers for Dye Workers

In the end of the nineteen century, little regard was paid to the safety and of dye worker labor conditions. However, it soon became apparent that there were deadly risks to workers who manufactured dye and who dyed garments.

In the dye industry in 2008, much, but not all has changed, and not even where you might expect it to. In Japan, dye workers are at higher risk of tumors. And in the United States, deaths amongst factory workers  from several cancers, cerebrovascular disease, lung disease are significantly higher – 40 times higher, for some diseases – than in the general population.

Environmental Pollution from Dye Factories

Almost every industrial dye process involves a solution of a dye in water, in which the fabrics are dipped or washed. After dying a batch of fabric, it’s cheaper to dump the used water – dye effluent – than to clean and re-use the water in the factory.  So dye factories across the world are dumping millions of tons of dye effluent into rivers.

Most countries require factories to treat dye effluent before it is dumped. Separating the dye chemicals from the water results in a dye sludge, and cleaner water. The water, which still contains traces of dye, is dumped into the river, and leaves the problem of what to do with the sludge?

China does have water pollution laws stipulating how dye waste water must be treated before it is discharged into rivers, but when the river downstream from a factory producing dyed textiles for Gap, Target and Wal-Mart ran dark red, investigators discovered that untreated dye effluent was being dumped directly into the river, close to 22,000 tons worth. Villagers say that fish died, and the lifeless river turned to sludge. The factory, a major supplier to several US stores, was attempting to save money in the face of companies like Wal-Mart’s pressure for ever-lower prices.  For more on this story, see the Wall Street Journal.

In Mexico, fields and rivers near jeans factories are turning dark blue from untreated, unregulated dye effluent. Factories dying denims for Levi and Gap dump waste-water contaminated with synthetic indigo straight into the environment. Local residents and farmers report health problems and wonder if the food they are obliged to grow in nearby fields is safe to eat.

Are Dyed Clothes Safe to Wear?

The dye on a finished garment, by it’s nature, is chemically stable – that’s what makes a dye color fast. However, research is emerging that examines the short and long term effects of potential skin absorption of dye and finishing chemicals through clothing. The CNN report October 2007 which Shana wrote about on Green Cotton, revealed that new testing procedures (chemical burden testing) reveal that young babies and children actually do have increased levels of chemicals in their bloodstream and skin. Because clothing comes into prolonged contact with one’s skin, toxic chemicals are often absorbed into the skin, especially when one’s body is warm and skin pores have opened to allow perspiration. We also know that some individuals have what is known as chemical sensitivity, including when exposed to garments of many types.  Symptoms in adults for chemical sensitivity range from skin rashes, headaches, trouble concentrating, nausea, diarrhea, fatigue, muscle and joint pain, dizziness, difficulty breathing, irregular heart beat, and/or seizures.  Symptoms in children include red cheeks and ears, dark circles under the eyes, hyperactivity, and behavior or learning problems. See for more information.

Dyes are complex chemicals, and as anyone who’s washed a red shirt with a white shirt knows, they don’t stay put forever.

Why Are Synthetic Dyes So Harmful?

Dyes are so problematic because the families of chemical compounds that make good dyes are also toxic to humans. Each new synthetic dye developed is a brand new compound, and because it’s new,  no-one knows it’s risks to humans and the environment.

Many dyes like Amaranth have entered the market, then have subsequently been discovered to be carcinogenic and withdrawn. The European Union in particular has been pro-active in banning dangerous dyes and dyes formulated from toxic chemicals.

But it’s backwards to create a dye, see if it’s hazardous, then ban it if so. Especially since so many dyes are known to be dangerous and carcinogenic.

In addition to the dyes them selves, the garment finishes are often equally as harmful. We will save discussion on garment finishes for another post, but just briefly, they are used for creating wrinkle-free, stain resistant, flame retardant, anti-static, anti-fungal, anti-bacterial, odor-resistant, permanent-press, and non-shrink fabrics. They can also be used as softening agents, and for creating other easy-care treatments. In fact it is often the dye fixative, used to bond the dye color to the fabric, that causes the most problems. All of these can be particularly challenging for people with chemical sensitivities.

What’s the Alternative to Synthetic Dyes?

So what is the dye industry doing, or rather innovators in the clothing industry who want to change the dye industry?  Responsible dye manufactures are investigating ways to treat their dye effluent with organic materials and bacteria, rather than chemical treatments, and improve  dye manufacture and processing to minimize hazardous chemicals used. In fact, I’m excited to learn that natural, plant based dyes are steadily making a comeback into mainstream fashion.

While, natural dyes will never be able to completely replace synthetic dyes, due to the fact that there is only so much land to go around and food is already in great demand. However, there are innovative ways of using plants for multiple purposes and maximizing their dying potential. And of course, if there was a little more love for the natural colors of fabrics, dyes wouldn’t be needed as much.

I’m in love with indigo denim– black is flattering, mysterious  and I also have a Tyrolean purple summer dress that I will wear forever. I love and respect naturals: cream and white and ivory and mushroom, but it will never be the only color in my wardrobe.

The realistic solution to current toxic dyes is likely to be a combination of more responsible synthetic dye production, together with a sustainable development of natural dyes.

Stay tuned for the next post on this topic: A look at natural dyes more closely….



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