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Synthetic Dyes: A look at Environmental & Human Risks

July 10, 2013

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
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. http://
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
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
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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