Archroma’s Denisol Pure Indigo 30 liquid dye launched in May as a non-toxic way to produce the traditional, iconic indigo blue that consumers associate with denim and jeans. The new dye is produced in Archroma’s facility in Pakistan, an award-winning “zero liquid discharge” plant.
Compared with conventional indigo dyeing, Archroma said an optimized process with Denisol Indigo 30 can offer up to 60 percent less sodium hydrosulfite, and up to 50 percent less sodium hydroxide.
During production, some of the aniline stays locked into the indigo pigment and is difficult to wash off the fabric. The remainder of the aniline impurity, about 300 metric tons annually, is discharged during dyeing.
The U.S. Environmental Protection Agency (EPA) classifies aniline as a Group B2 human carcinogen, meaning there is some evidence it could cause cancer in people. Aniline can cause skin allergies with repeated contact and exposure to the chemical, either through the lungs or the skin. It can impair the ability of red blood cells to carry oxygen to tissues, which can trigger symptoms of hypoxia such as headaches, dizziness, increased heart rate, breathlessness and even unconsciousness, according to the EPA. It’s also “very toxic” to aquatic life, according to the U.S. Centers for Disease Control and Prevention.
According to Scott Echols, director of the Roadmap to Zero program at ZDHC, however, “there is no compelling evidence that there is a problem at the levels reported, even considering worst-case scenarios.”
Archroma tested Denisol Pure Indigo at Absolute Denim’s mill in Thailand because it wanted to be sure the new indigo dye would perform exactly the same as conventional indigo.
“At Archroma, we continuously challenge the status quo in the deep belief that we can make our industry sustainable, but we cannot do it alone,” James Carnahan, head of sustainability at Archroma, said. “Without forward-thinking manufacturers such as Absolute Denim to consciously adopt these eco-advanced innovations in their daily production, like our aniline-free Denisol Pure Indigo, we will not be able to move this industry forward on our resource-constrained world we live in.”
Absolute Denim produces up to 2 million meters of denim per month for major brands and retailers in the world. The company makes denim with a focus on eco-friendly materials and processes.
Vichai Phromvanich, board member at Absolute Denim, said, “Archroma’s aniline free indigo project is therefore something we as a new generation manufacturer have supported from the beginning, by opening our doors for tests in the project phase, and now by sending out our articles to many of our customers. For us, after all, a nice pair of jeans looks even nicer without aniline.”