Wearing black underwear makes you more likely to get cancer? The truth is out

Black is one of the most common colors in textile and clothing products, but recently there has been a rumor online that "it is best not to buy black underwear." Some even say that wearing black underwear will increase the risk of cancer. Are these claims reasonable?

Let me first say the conclusion: Don’t worry too much.

The focus of the saying "Don't buy black underwear" is actually the dyeing safety of black clothing, including whether the dyes used in the dyeing process are safe, how is the color fastness after dyeing, etc. Let's talk about it in detail.

Is black dye unsafe?

At present, the dyes used in the textile industry (including black dyes, of course) are mainly chemical synthetic dyes, which are non-toxic in themselves.

It is worth noting that among chemical synthetic dyes, there is one type of dye that accounts for the largest proportion - azo dyes. Because their molecular structure contains azo-connected aniline structure, they involve most commonly used reactive dyes, disperse dyes, direct dyes, etc., and are used for dyeing and printing a variety of natural and synthetic fiber fabrics.

Similarly, azo dyes themselves are non-toxic, but a small part of them will mix with the body's metabolites when worn, undergo reduction reactions under certain conditions, and release carcinogenic aromatic amines, which will damage human health.

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However, you can rest assured that these azo dyes have been banned in most countries. my country's national mandatory standard GB18401-2010 "National Basic Safety Technical Specifications for Textile Products" clearly stipulates that "degradable carcinogenic aromatic amine dyes are prohibited"; the mandatory standard GB19601-2013 "Limits and determination of 23 harmful aromatic amines in dye products" regulates the development and production of dye products in my country from the source, ensuring that high-quality and safe products are provided to companies that use dyes for textile and clothing products.

Textile and clothing products sold in the Chinese market must comply with the provisions of GB18401-2010, and the dyes used in these products must also comply with the provisions of GB19601-2013 to ensure that the textile and clothing products that ultimately reach consumers are safe and harmless.

Therefore, as long as the clothing is of qualified quality, no matter what color it is, it is safe and harmless. The above regulations also apply to black textile and clothing products, and qualified black textile and clothing products are also safe and harmless.

Does fading mean it’s unsafe?

Some consumers have reported that some black textile and clothing products "stain" their skin after wearing. There are two main reasons for this: first, insufficient washing during production results in residual floating color on the product; second, the color fastness of the product does not meet the standard, and the dye is transferred to the surface of the skin under the action of human sweat or skin friction.

The national standard GB18401-2010 "National Basic Safety Technical Specifications for Textile Products" stipulates the color fastness levels under five scenarios, namely color fastness to water, color fastness to acid perspiration, color fastness to alkali perspiration, color fastness to dry friction, and color fastness to saliva, as shown in Table 1.

Table 1 Requirements for color fastness in GB18401-2010

Note: This requirement is not applicable to non-final products, natural color and bleached products that must be washed and faded; it is not applicable to traditional hand-dyed products such as tie-dye and batik; the color fastness to saliva is only tested for textile products for infants and young children. Source: GB18401-2010 "National Basic Safety Technical Specifications for Textile Products"

The standard stipulates that infant textile products should meet Class A requirements, products that come into direct contact with the skin should at least meet Class B requirements, and products that do not come into direct contact with the skin should at least meet Class C requirements.

When purchasing textile and clothing products that come into direct contact with the skin, consumers should choose Class B or Class A products, and for infant textile products (such as diapers, underwear, bibs, pajamas, gloves, socks, outerwear, hats, and bedding), they should choose Class A products to avoid safety hazards and embarrassment caused by substandard color fastness.

Is dyeing it black to cover blemishes?

There is also a rumor that "poor quality fabrics are often dyed black to cover up defects in the fabric." This idea can be said to be still in the hand-woven stage...

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At present, the fabric weaving process in the modern textile industry has achieved large-scale automation and intelligent production, and the level of fabric quality control has also been very high. Some companies have applied artificial intelligence visual inspection technology to realize online production monitoring of fabric quality and finished product inspection.

From weaving to dyeing of a roll of cloth, each link is subject to quality inspection and monitoring to improve quality and reduce defect rate. The weaving structure of a roll of cloth and the color it is dyed are all planned by the company in the design stage, and the company will not pick out the cloth and dye it black just because the weaving is faulty.

To conclude, the statement that “it is best not to buy black underwear” is untenable. For textile and clothing products that comply with national safety technical specifications, you can rest assured to choose black. Besides, black makes you look thinner, right?

Here, consumers are also reminded that when purchasing clothing, they should buy products with quality assurance from regular channels and check whether the products have complete identification or tags, including whether the product name, implemented product standard number, manufacturer name and address, product model or specifications, safety category, fiber composition and content, maintenance methods, product quality inspection certificate, etc. are clearly marked.

It is recommended to be cautious when buying clothing with unclear labels, unclear content, or too cheap prices. It is recommended to properly wash newly purchased textile and clothing products (especially those that come into direct contact with the skin) to remove any floating colors that may exist on the textile and clothing products, so that you can use them with more confidence.

References [1] Shi Yidong. Ecological textiles and environmentally friendly dyeing auxiliaries [M]. China Textile Press, 2014. [2] Wu Zanmin. Dyeing and finishing of knitted fabrics [M]. China Textile Press, 2009. [3] GB18401-2010, National basic safety technical specifications for textile products [S]. [4] GB19601-2013, Limit and determination of 23 harmful aromatic amines in dye products [S].

This article is a work of Science Popularization China-Starry Sky Project

Produced by Science Popularization Department of Science Popularization China

Producer: China Science and Technology Press Co., Ltd., Beijing Zhongke Xinghe Culture Media Co., Ltd.

Author: Song Lidan China Textile Construction Planning Institute

Review丨Zhang Jie, Chief Engineer of China Textile Construction Planning Institute