TAIPEI (Taiwan News) — The health authorities are embarking on a mass inspection of medical masks in Taiwan to determine whether they contain illegal azo dyes, a class of synthetic dyes that can be toxic and carcinogenic.

Taiwan currently allows the use of 22 azo colorants, said Central Epidemic Command Center (CECC) Spokesman Chuang Jen-hsiang (莊人祥) on Sunday (Jan. 3). The Cabinet-level Consumer Protection Committee found that the colorants have been illicitly used in colored masks purchased from shopping websites, reported Liberty Times.

Inspections of medical masks in the country have so far been focused on their ability to filter out viruses. With masks in various hues sprouting up everywhere, whether the protective gear could pose a health risk due to azo dyes has become a public concern.

The Bureau of Standards, Metrology and Inspection on Monday (Jan. 4) started screening a batch of 70 surgical mask samples bought from both online and brick-and-mortar stores. The results are expected to be out in two weeks, wrote CNA.

Violations could incur a maximum fine of NT$1.5 million (US$53,373) pursuant to the Consumer Protection Act. Mask manufacturers found to have used illegal azo dyes will also be subject to a fine of between NT$30,000 and NT$2 million, in line with the Pharmaceutical Affairs Act.

Some azo dyes could break up and release aromatic amines, many of which are carcinogenic. Colored masks may also contain heavy metals, UDN quoted Consumer Protection Committee official Wang Te-ming (王德明) as saying.