The FAQ on Azo Dyes


What are azo dyes?

Azo dyes are a large group of synthetic dyes that contain nitrogen. More than 50% of commercial dyes belong to this class. The discovery of azo dyes brought about the evolution of ingrain dyeing, where dye is bonded to the fabric. This process usually involves chemical compounds within cotton, silk, wool.

Where are azo dyes used?

Azo dyes are used in pharmaceuticals, cosmetics, food, and textiles. These dyes are the largest and most versatile class of dyes, especially since they possess exquisite bright colors (oranges, reds and yellows). Moreover, these dyes are well known for their antibiotic, anti-HIV, and anti-fungal properties. However, they are carcinogenic and mutagenic.

How do azo dyes threaten health?

When in contact with skin, azo dyes can cause skin irritations, eye problems (such as swelling, excessive tears, and even permanent blindness), acute kidney failure, hypertension, and vertigo. When ingested, these dyes can cause swelling of the face, neck, throat, and tongue on with respiratory distress.

'Millions' of clothing items contain azo dyes

‘Millions’ of clothing items contain azo dyes

Ecological impact

Obviously, the textile industry’s wastewater is the most environmentally damaging among all the industrial sectors. Textile factories release their chemical waste into rivers, which threatens the ecosystem.


  • Water remediation

In many countries, it is mandatory for textile dyeing factories to install water treatment plants to make the wastewater safe before it leaves the factory premises. Because many international clothing buyers are concerned about textile pollution, these plants are integral in order to sustain business in the competitive market.

Meanwhile, these treatment plants are not seen as an effective way of cleaning water since azo dyes do not completely dissipate when treated with conventional methods. No treatment method works completely.  Some are more effective than others, but they still do not completely neutralize the dyes and are expensive and time-consuming.

  • Other methods

Over the years, scientists have proposed some cheap methods, which should be looked into. These are:

  1. Zero valent iron degradation processes, which uses zero valent iron to break down harmful chemicals
  2. Fungal degradation
  3. Bacterial remediation  
  4. Waterless dyeing technology  
  5. Synthetic biology

Back to basics

Hand block-printing is the oldest and the slowest form of textile printing on fabrics. The designs are carved into blocks soaked into oil for 15 days, and then the printers coat the blocks in organic vegetable and mineral dyes before applying the designs to fabrics. However, this process is slowly being phased out due to its lengthy procedure and dependence on the weather.

Although technology has made work quick and easy, it comes with its downsides. The discovery of azo dyes and the building of textile plants have been a great way of meeting the vast demand for textile products which are beautiful, well printed and of export quality. Yet the effect of these dangerous dyes on the environment has been severe to both the flora and fauna in the ecosystems and the surrounding communities and neighbourhoods. Thus, it’s time to yield safety over aesthetics; life over money.

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Author Edilhynie Jambangan

About the Author

Edilhynie has dreamed of becoming a book writer, an art exhibitor, a photographer and a cook. However, fate has put her in the field of education where she has taught English to high school students. She is now currently a high school principal and a school paper moderator. Her passion in writing has helped her inspire future journalists, her artistic skills has given her a leeway into a different realm, her love of photography has helped her see simple things as extraordinary, her love for cooking has saved her from hunger. She aspires to travel different places around the world and to write, to capture, and to savor her experiences - to be shared to the people.


  1. Pingback: - Trusted Clothes

  2. The dyeing problem is serious. People get ill working with them, but fashion shoppers never think about this.
    Everything is about the pharmaceutical industry these days.

  3. so, after reading this article, i know now that the employees at american airlines and delta have been greatly affected by the dyes in the uniforms that were made in 3rd world countries…it’s obvious, the airline corporations are “ok” with hurried, mass production. now, thousands of employees at AA and Delta have been poisoned by the chemicals in the dyes and factory conditions…

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