Shake your mask before wearing it to get rid of carcinogens? Here comes the rumor debunking!

[This issue's rumor]: Recently, a video saying "there are carcinogens in the disinfection residue of masks, so you should shake the mask before using it" has been widely circulated on the Internet. The video says that when wearing a mask, the unsealed mask should be swung or shaken in the air 10 to 20 times, otherwise directly wearing a mask that has been disinfected with ethylene oxide will have a risk of cancer.

[NetEase Health Assessment]: Unscientific!

【Rumor Identification Points】:

1. Toxicity cannot be discussed without considering the dose

Ethylene oxide is an organic compound. As an important petrochemical product and disinfectant, it is widely used in the washing, pharmaceutical, printing and dyeing industries. Exposure to high concentrations of ethylene oxide can indeed cause damage to the human body and lead to cancer risks. However, it is not scientific to talk about toxicity without considering the dosage.

According to the national industry standard "Medical Surgical Masks" (YY0469-2011), the residual ethylene oxide content in masks after ethylene oxide sterilization should not exceed 10μg/g. The video circulated online also pointed out that the five masks tested were all below the national prescribed values.

Screenshot from "Medical Surgical Mask" (YY0469-2011)

2. Masks have strict production process

Masks sterilized with ethylene oxide need to be air-dried in a ventilated desorption room for one to two weeks to wait for the ethylene oxide to dissipate, and then undergo sterility testing. Only when they meet the standards can they be shipped out of the factory. Zhu Lin, deputy chief physician of the Disinfection Department of the Chaoyang District Center for Disease Control and Prevention in Beijing, also mentioned in an interview with the media that mask manufacturers need to wait until the ethylene oxide evaporates before packaging. Therefore, we can use masks produced by regular companies with confidence.

3. Not all masks need to be sterilized with ethylene oxide

In addition to using ethylene oxide for disinfection, some masks are also made in sterile workshops. For example, when the national epidemic situation was at its most severe in 2020, large quantities of masks were disinfected by radiation.

4. The “shaking” action is unscientific

The practice of shaking the mask to volatilize ethylene oxide residue has no scientific basis and may lead to mask contamination.

The correct way to wear a mask is to wash your hands before putting it on. Do not touch the inside of the mask with your hands. If you need to take it off, you can find a clean tissue to wrap the mask or hang it up. In theory, disposable medical surgical masks should be replaced after 3 to 4 hours of use, and discarded masks should be disposed of in a timely manner according to garbage classification.

[Reference source for identification]: Scientific rumor refutation, Beijing Daily

【Note】Cover photo source: moodboard/IC photo