For the past few years, skin care fanatics around the world have been obsessed with sheet masks, the superconvenient, incredibly effective facial treatment trend from Korea [1]. But reports of unsanitary packaging processes may change everything.

Racked reports that Reddit user dvaonline22 [2], who claims to be a Seoul-based Korean woman with beauty industry experience, shed light on the unhygienic conditions surrounding the way sheet masks are made [3].

While you may have pictured your favorite sheet masks being created in a pristine skin care factory, this is not the case for many of these products. According to Racked, several brands use at-home labor for packaging sheet masks.

Dry masks and envelopes are delivered to mask employees' houses, where they use a guide to fold the paper, then insert it into the envelope. Once the final product is picked up, the factory fills the packet with serum and seals it, making it ready for use. Though this kind of at-home labor is illegal, it is quite common, and apparently it's seen as a way for housewives to earn extra money. (It's not very much, though: Racked found that this job could earn you approximately $5 an hour.)

마스크팩 위생상태에 대해 말이 많았지만 메디힐 너마저 그럴 줄은 몰랐다;; 재활용한 종이 쪼가리로 접는 건 너무하지 않나. 시드물이 마스크팩 설명에 백프로 기계공정 어쩌고 강조했던 이유를 이제야 알겠네... pic.twitter.com/KWNjOhGKTe [4]

— 화장품 오따꾸 (@dotorucom) June 9, 2016 [5]

Some companies claim that they sterilize each envelope before essence is added, and products are subjected to microbial checks. But debris like hair — and even a dead insect — has been found inside some sheet mask packaging.

And even if your favorite product is manufactured in a factory, there's a chance that it's not as sterile as you believed it to be. This post by a Korean blogger [6] who claimed to work part-time for one of these brands noted that workers are smoking cigarettes during their shifts (not on breaks outside, but while they're actively working and making masks). It's not surprising, then, that another blogger opened a sheet mask to discover it reeked of nicotine [7].

While we're sure that not all skin care brands operate under these conditions, we know that we'll be thinking twice before using any sheet masks in the foreseeable future. Read Racked's gripping exposé here [8] then visit Reddit to see which brands' practices are being questioned [9].