news Taiwan Is Investigating Coloured Face Masks To See If They Contain Cancer-Causing Dyes Coloured face masks can be easily found on Malaysian e-commerce sites, being sold for as low as RM5.85 for 50 pieces. By Yap Wan Xiang â 08 Jan 2021, 06:39 PM The health authorities in Taiwan are investigating whether or not coloured face masks in the market contain illegal azo dyes â a substance known to be carcinogenic and toxic According to Taiwan News, the authorities' previous inspections only focused on face masks' ability to filter out viruses. But as of late, with more coloured face masks being sold in the market, concerns are running high on whether these face masks are safe for use.